-
Table of Contents
RC-28S/RC-24 Service Manual Supplement
Paragraph Page
Part 1: RC-24 Service Information ............................. 1
Description ........................................... 1
Operation ............................................ 1
Repair & Replacement................................... 1
Diagnostics ........................................... 1
Calibration ........................................... 2
Illustrated Parts. ....................................... 2
Part 2: Voltage Conversion................................... 3
Part 3: Drive Control & Power Distribution Theory ................. 5
Drive Specifications ..................................... 5
General Description of Drive Control Electronics ............... 5
Drive System Performance................................ 10
Power Distribution Box Theory ............................ 12
Electronic System Glossary ............................... 14
Part 4: Repair and Replacement............................... 18
Relay Printed Circuit Board Replacement..................... 19
Circuit Breaker/Fuse Switch Replacement. ................... 20
Solid State Relay Replacement............................. 20
Changing the Vacuum Pump Oil ........................... 21
Drive Motor Replacement................................. 21
Drive Motor Fan Replacement ............................. 27
Drive Control Module Replacement ......................... 27
Part 5: Diagnostics & Fault Troubleshooting ..................... 28
Screen 1. Fault Messages ................................ 28
Screen 2, User DIAGNOSTICS ............................. 29
Screen 3, Service DIAGNOSTICS ........................... 29
Part 6: Operational Checks & Troubleshooting. ................... 97
Part 7: Printed Circuit Boards & Schematic Diagrams .............. 107
Part 8: Illustrated Parts ..................................... 147
List of Illustrations
Figure Page
1 RC-24 DIAGNOSTIC Mode Access .......................... 1
2 Voltage Conversion ..................................... 4
3 Input and Output Signals. Drive Control Module ............... 8
4 Power Distribution Box Input/Output ....................... 13
5 Parts Identification. Vacuum Pump Oil Change ................ 22
6 Parts Location, Drive Motor Replacement..................... 24
7 Bad AC Power Relay, Flow Chart ........................... 31
8 Bad Brake Monitor Circuit. Flow Chart ...................... 33
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List of Illustrations (continued)
Figure Page
9 Bad Drive Accel. Flow Chart .............................. 34
10 Bad Min Speed Monitor. Flow Chart. ........................ 35
11 Bad Speed Control. Flow Chart ............................ 36
12 Calrod Overtemp, Flow Chart ............................. 37
13 Can't Reach Full Vacuum, Flow Chart ....................... 38
14 Ctrlr Drive Enable Out. Flow Chart ......................... 39
15 Door Locked Switch. Flow Chart ........................... 41
16 Door Not Closed. Flow Chart .............................. 43
17 Door Not Latched. Flow Chart ............................. 44
18 Door Not Locked. Flow Chart.............................. 45
19 Door Open Switch, Flow Chart. ............................ 46
20 Drive Enable (Ctrlr off). Flow Chart ......................... 47
21 Drive Enable (H & C off), Flow Chart ........................ 48
22 Drive Enable (Host off). Flow Chart ......................... 49
23 Drive Failed To Start, Flow Chart. .......................... 51
24 Drive Still Enabled. Flow Chart ............................ 55
25 Dv-Enab FALSE Refused, Flow Chart. ....................... 56
26 Dv-Enab TRUE Refused. Flow Chart ........................ 57
27 High Chamber Temp, Flow Chart. .......................... 58
28 High Drive Temperature. Flow Chart ........................ 59
29 Improbable Speed Chng, Flow Chart ........................ 60
30 Inertia Out of Range. Flow Chart ........................... 61
31 Inertia Too High. Flow Chart .............................. 62
32 Inertia Too Low, Flow Chart............................... 63
33 Inoperable Vacuum, Flow Chart............................ 64
34 Instrument Overspeed. Flow Chart ......................... 65
35 Loss of Tachometer, Flow Chart............................ 67
36 Low Chamber Temp. Flow Chart ........................... 69
37 No Ctrlr Drive Disable. Flow Chart.......................... 70
38 No Ctrlr Drive Enable. Flow Chart .......................... 71
39 No Deed Detected. Flow Chart............................. 72
40 No Door Unlock, Flow Chart .............................. 73
41 No Drive Enable (H & C). Flow Chart ........................ 75
42 Open Winding Sensor. Flow Chart .......................... 77
43 Rotor Overspeed. Flow Chart .............................. 78
44 Rotor Overtemp, Flow Chart .............................. 79
45 Shorted Winding Sensor. Flow Chart ........................ 83
46 Speed Overshoot Trap, Flow Chart. ......................... 84
47 Temp Out of Range, Flow Chart............................ 85
48 Vacuum Loss. Flow Chart ................................ 87
49 Vacuum Release Failure, Flow Chart ........................ 89
50 Warn - Marginal Vacuum, Flow Chart ....................... 91
51 Warning - Hot Gas Failed. Flow Chart ....................... 93
52 Warning - Low Accel. Flow Chart........................... 95
53 Warning - Poor Brake. Flow Chart .......................... 96
54 LED Supply Check. Flow Chart ............................ 103
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List of Illustrations (continued)
Figure Page
55 24V Supply Check Flow Chart ............................. 105
56 Motor Winding Continuity Check Flow Chart .................. 106
57 System Wiring Diagram .................................. 109
58 System High Voltage Wiring Diagram........................ 113
59 Schematic. Controller Printed Circuit Board, 59855-0 ........... 117
60 Component Location. Controller Printed Circuit Board. 59855-0 ... 129
61 Schematic, Relay Printed Circuit Board. 59745-0 .............. 139
62 Component Location. Relay Printed Circuit Board, 59745-0....... 141
63 Wiring Diagram. Power Distribution Box ..................... 145
64 Console and Cabinet Assembly, Illustrated Parts ............... 148
65 RC-28S Main Assembly. Illustrated Parts. .................... 150
66 Power Distribution Box Assembly. Illustrated Parts ............. 152
67 Wiring Harness Identification. ............................. 153
List of Tables
Table Page
1 Drive Control Module and Controller Interface Signals........... 7
2 Drive Control Module Signal Descriptions .................... 8
3 Electronic System Glossary ............................... 14
4 Lights, Relay Control P. C. Board........................... 97
5 Lights. Controller P. C. Board ............................. 98
6 Lights. Drive Control Module .............................. 100
7 Control Logic Signals ....................................111
8 Component Identification. Controller P. C. Board, 59855-0 ....... 131
9 Component Identification. Relay P. C. Board, 59745-0 ........... 142
10 Parts List, Console and Cabinet Assembly .................... 149
11 Parts List, RC-28S Main Assembly.......................... 151
12 Parts List, Power Distribution Box Assembly .................. 152
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SORVALL® Centrifuges RC-28S/RC-24 Service Manual
Supplement
Part 1: RC-24 Service Information
a. Description
The RC-24 Centrifuge is a superspeed version of the RC-28S SUPRAspeed® Centrifuge
with the following differences:
• no vacuum, system,
• no SPIN-RIGHT® Rotor Management System,
NOTE
Since the RC-24 does not have a vacuum system or a SPIN-RIGHT® Rotor
Management system (URR), please ignore all references to these throughout
the manual.
• a top speed of 24 000 rpm with maximum g force of 60 028 (when used with the
SORVALL SE-12 Rotor),
• no user accessible DIAGNOSTIC mode, and
• no CALCULATE mode.
b. Operation
The operation of an RC-24 is slightly different than operation of an RC-28S because the
PROGRAM key has been replaced by a MODE key and key number access is not required.
For operating procedures, refer to the RC-24 Instruction Manual (PN 59874) or to the RC-
24 Operator's Guide (PN 59870) stored under the control panel.
c. Repair & Replacement
The RC-24 does not have an access panel behind the front cabinet panel. Also. because
it does not have a vacuum system or a SPIN-RIGHT* Rotor Management System, it does
not have an encoder assembly, ultrasonic transducer, URR printed circuit board, door
open switch, or any of the vacuum system components. Therefore, when performing the
repair and replacement procedures in Section 4, pass over any steps that refer to these
parts. The RC-24 has the same Drive Control Module as the RC-28S (SN 9002294 &
above), so the information in the Service Manual Supplement is applicable to the RC-24.
d. Diagnostics
Use the following procedure to access DIAGNOSTICS:
1. Turn the centrifuge power OFF.
2. Remove the front control panel from the control console, then lay the panel on the
centrifuge deck with the keypad facing up.
3. Set the centrifuge to operate in the DIAGNOSTIC mode by moving the two jumpers
stored on the Host P. C. Board to the DIAGNOSTIC position as shown in figure 1.
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RC-28S/RC-24 Service Manual
Supplement
SORVALL® Centrifuges
4. Turn the centrifuge power ON, and press the control panel at the location shown in
figure 1 to turn DIAGNOSTICS on.
NOTE
The switch to turn on DIAGNOSTICS is located in the same position as the
RC-28S but there is no key on the control panel to press. Figure 1 shows
the key superimposed over the location of the switch.
HOST BOARD
JUMPER PLUG
POSITIONING
NORMAL
JP-iBn
JP2fln
JP3H°
JP4H°
DIAGNOSTICS
JP1 oo
JP2 0 o
DIAGNOSTICS MODE
SWITCH LOCATION
Figure 1. RC-24 DIAGNOSTIC Mode Access
5. When you are done using the DIAGNOSTIC mode, turn the centrifuge power OFF and
move the two jumpers back to their original position (see figure 1) for storage on the
Host P. C. Board.
6. Reassemble the control console.
e. Calibration
The Controller Drive and the Imbalance System calibration procedures are different for the
RC-24 than the RC-28S. The procedures in Section 8 have been revised to reflect these
changes and new pages are provided in the Update Information (5/91).
f. Illustrated Parts
Following are the new part numbers for the RC-24:
• PN 59867. Bezel, Control Panel. Front (Table 10, item 6);
• PN 59870, Instructions. Operator's Guide, RC-24 (Table 10. item 16);
• PN 59865, Door Plate (Table 10-4. item 20);
• PN 59861. SORVALL RC24/DU FONT oval. front panel decal (Table 10-10); and
• PN 66724, jumper plug. blue. Host P. C. Board.
-
SORVALL® Centrifuges
Part 2: Voltage Conversion
RC-28S/RC-24 Service Manual
Supplement
NOTE
Use this procedure in place of the one in the Service Manual, Section 2,
paragraph 2-6. Two new labels are required for this procedure: PN 59711,
Power Distribution Box label and PN 59713, Rating Conversion label.
111^^^^
The centrifuge has high ^
electrical shock. For this reason, this procedureshould only be done by a
technician who is familiar with electronics. Before beginning this: proce¬
dure, be sure the centrifuge power is OFF and the power cord is unplugged. I:
1. Turn the centrifuge power OFF. and unplug the power cord.
2. Remove the right-side cabinet panel from the centrifuge.
3. Disconnect all plugs from the top of the Power Distribution Box.
4. Remove the Power Distribution Box mounting screw from the rear of the box, and
remove the box from the centrifuge. Place the box on a clean, flat work surface.
5. Turn the 1 /4-turn fastener on the side of the Power Distribution Box counterclockwise,
and remove the panel from the box.
6. Locate terminal block TB 1. then refer to figure 2 and rearrange the wires to the desired
configuration.
7. Reassemble the Power Distribution Box.
8. Install the Power Distribution Box back in the centrifuge, and secure it in place using
the screw removed in Step 4.
9. Reconnect all plugs to the top of the Power Distribution Box.
NOTE
If changing configuration from one phase to another, raise the front locking
stabilizers and pull the centrifuge away from the wall. Remove existing
power cord from the rear of the centrifuge, and connect new power cord
as shown in figure 2.
10. Write the new specifications (voltage, phase, and frequency) on both labels. Peel the
back off label PN 59713 and stick it over the label on the back of the centrifuge. Peel
the back off label PN 59711 and stick it over the label on the Power Distribution Box,
making sure it doesn't cover any vent holes in the box.
11. Reinstall the right-side cabinet panel. If centrifuge was moved away from the wall.
push it back In location, lower front locking stabilizers, and level the centrifuge.
3
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RC-28S/RC-24 Service Manual
Supplement
SORVALL® Centrifuges
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-
SORVALL® Centrifuges RC-28S/RC-24 Service Manual
Supplement
Part 3: Drive Control & Power Distribution Theory
NOTE
This information replaces all drive control electronics and power distribu¬
tion theory of operation information in Section 3 of the Service Manual.
a. Drive Specifications
Weight ............................. 15.4 Kg (34 Ib)
Size ............................... 50.2 cm L x 33 cm H x 14.3 cm W
(19.75 in x 13 in x 5.6 in)
Outside dimensions do not include
the mounting tabs.
ac Power Required .................... 187 to 242 Vac. 50/60 Hz,
single phase
Inverter ............................ dc Brushless Drive, 20 A, 3 phase,
6 step. pulse width modulated (PWM)
PWM Frequency (motor power) ........... 22 Khz, ± 5%
PWM Frequency (control signals) ......... 4.8 Khz, ± 5%
Output Current ...................... 0.25 to 20 A, 3 phase
Operating Temperature Range ........... +10 to +50°C
Storage Temperature Range ............. -20 to +85°C
Operating Humidity Range .............. 5 to 95% noncondensing
Cooling............................. Forced air ventilation, vented
out the bottom of the drive
enclosure.
b. General Description of Drive Control Electronics
This is a power inverter motor drive. Its functional purpose is to convert raw single phase
ac power into synchronous 3-phase power to the motor. This is accomplished in several
stages. Following is a description of how the internal power conversion process occurs.
ac to dc Power Conversion
The ac power source may be in the range of 187 to 242 Vac-RMS at a frequency of between
48 to 62 Hz. Only single phase ac is used. Separate ac power ports are provided to the
5
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RC-28S/RC-24 Service Manual
Supplement
SORVALL® Centrifuges
Drive Control Module for both motor power and logic hardware power. This provides the
centrifuge with the ability to effect ultimate shutdown control over the motor while the
drive logic hardware remains in a standby mode, should a serious problem develop.
The raw ac power used for the motor passes into a full wave bridge rectifier. From there
it passes through a line choke and into a bank of filter capacitors. The combination of these
components provides a high voltage unregulated dc power source. The choke functions
as a low pass line filter to reduce the effects ofac line noise and surges from passing into
the Drive Control Module. It also serves to help improve the form factor ofac line current
flowing into the Drive Control Module when the motor is in operation.
dc to ac Power Inversion
The high voltage unregulated dc power available in the Drive Control Module must be
converted back to phased ac power in order for the motor to operate. This process is called
inversion. To properly control motor rotation, the drive electronics must synchronize the
application of power precisely with the rotational position of the rotor. This process is
commonly referred to as commutation. The motor used in this centrifuge requires three
phase ac power for commutation.
The three phase ac power used to commutate the motor is phase displaced in time by 120
electrical degrees, not unlike the three phase 50/60Hz ac power available from a power
company. Two major differences exist between them. The first is that the ac power
delivered by the drive is not sinusoidal like that delivered from a power company, but
rather it delivers pulsed square waves. The second major difference is that the drive must
provide variable frequency ac to the motor rather than the fixed frequency ac supplied by
the power company. This feature enables the motor to operate at variable speeds.
The three phase ac power delivered to the motor is developed by an active circuit network
consisting of six power transistors. This network is called the output bridge. In order to
sustain the rotation of the centrifuge, the Drive Control Module continuously processes
and decodes rotor position information. This information is used to sequentially apply
power from the output bridge to the motor.
Motor Torque and Speed Control
It is not sufficient to precisely control the motor through commutation alone. The power
applied to the motor must be carefully metered in order to throttle both torque and speed.
This is accomplished through a technique called pulse width modulation, or PWM.
The PWM technique provides a method of efficient power control through the use of high
frequency output bridge modulation. In effect, as each motor winding is turned ON in
sequence during motor rotation. PWM is superimposed upon the normal commutation
signals. PWM results in the application of power to the motor by chopping it ON and OFF
at a high rate (i.e., 22 kHz). This chopping scheme controls average motor current by
varying the ratio of ON time versus OFF time for each PWM modulation cycle. This
chopping scheme provides proportional output torque from the motor through the direct
adjustment of the average motor current.
The Drive Control Module limits torque by continuously monitoring the electrical current
flowing to the motor and comparing it to the commanded level requested by the control
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SORVALL® Centrifuges RC-28S/RC-24 Service Manual
Supplement
console. The difference between these two levels results in an error signal which is then
converted to a PWM ratio. This PWM ratio is used to modulate the output bridge as
described above.
Motor speed is limited by the control console computer. Using a tachometer signal
supplied by the Drive Control Module, the control console throttles speed through a fine
torque adjustment of the TORQUE DEMAND signal. The drive does not have any means
to regulate motor speed itself.
Control Interface
All input and output communications between the control console and the Drive Control
Module pass through interface connector, J33. which consists of 20 pins. The signals
supplied to the drive from the control console are all electrically isolated from the internal
drive logic hardware. This isolation is provided by means of optical isolators.
The logic signals used to operate the control Interface are all digital in nature. No analog
signals are used. These digital signals are all using +5 volt logic levels.
The Drive Control Module is interfaced with the Controller P. C. Board by a 20-pin ribbon
cable. The signals and their pin designations are listed in Table 1. The signals are
illustrated in figure 3 and described in Table 2.
Table 1. Drive Control Module and
Controller Interface Signals
Pln#
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
Signal Name
REF PWM*
EXTERNAL POWER +5Vdc
BRIDGE ENABLED*
EXTERNAL COMMON
FORWARD ENABLE*
FORWARD ENABLE PWR
ABMINSPD
EXTERNAL POWER +5Vdc
FULL CHOP*
EXTERNAL POWER +5Vdc
BRAKE ENABLE*
EXTERNAL POWER +5Vdc
MOTOR TEMP+
MOTOR TEMP-
SHUNT ACTIVE
EXTERNAL POWER +5Vdc
NOT USED
EXTERNAL POWER
TACHOMETER
EXTERNAL COMMON
Function
Sets the motor current
+5V optocoupler supply input
FORWARD ENABLE* feedback to Controller
Controller common
Sets forward direction
Led supply for signal FORWARD ENABLE*
Above minimum speed
See pin 2
Selects chopping mode
See pin 2
Selects normal or brake mode
See pin 2
Motor temperature sensing
Motor temperature sensing
Brake activity monitor
See pin 2
See pin 4
Tachometer feedback to Controller
See pin 4
"The asterisk indicates this is a NOT (active low) signal.
7
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RC-28S/RC-24 Service Manual
Supplement
SORVALL® Centrifuges
TO CONTROLLER
P.C. BOARD N33^
FROM MOTOR
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=ULL CHOP*
BRAKE ENABLE*
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GROUND
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MODULE
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/ -1 ^ ' POWE
———————
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SORVALL® Centrifuges RC-28S/RC-24 Service Manual
Supplement
Table 2. Drive Control Module Signal Descriptions
(continued)
Signal Description
EXTERNAL
POWER +5Vdc
BRIDGE
ENABLED*
EXTERNAL
COMMON
FORWARD
ENABLE*
FORWARD
ENABLE
POWER
ABMINSPD
The source for the +5 Vdc power used by most of the optical
coupler devices In the drive Interface. The only exception is the
optical coupler used for the FORWARD ENABLE* signal. This
power is sourced from the control console.
This signal originates within the Drive Control Module. It
indicates to the control console that the Drive is commutating
the motor in the forward direction. Conditionally, it is in a low
logic state when there are no faults registered in the Drive,
FORWARD ENABLE* is in a logic low state, and the BRAKE
ENABLE* signal is in a logic high state.
The local ground for all signals sourced into and out of the
drive interface. All voltages at this interface are referenced
to these pins.
This signal originates at the control console. When this signal
is in a logic low state and the BRAKE ENABLE* signal is in a logic
high state, the motor is being commanded to rotate in the for¬
ward direction. Forward motion by the motor will be aborted if
the BRIDGE ENABLED* signal is in a high state or if the BRAKE
ENABLE* signal is in a low state at the same time the BRAKE
ENABLE* signal is in the logic high state.
This is the separate +5 Vdc power supply input pin for exclu¬
sive use by the optical coupler that accepts the FORWARD EN¬
ABLE* signal from the control console. This supply is turned off
if the control console power supply does not operate properly.
If this happens, the Drive will not allow rotor to accelerate nor
will it maintain forward velocity.
The above minimum speed signal which originates within the
Drive Control Module. It is in a logic high state whenever the
motor back EMF voltage indicates that it is rotating above
2000 rpm during a coasting condition. A coasting condition
occurs when rotor is in motion but the control console is not
commanding either a forward drive or brake state. Below 500
rpm, this signal is in logic low state during a coast condition.
Speeds from 500 to 2000 rpm yield an unstable signal seen as
rapid toggling from one logic state to another. Whenever the
control console commands either a forward or brake state and
the Drive is not in a fault condition, ABMINSPD will remain in
an Invalid state. Signal is only valid when the bridge has been
off for >200 ms.
'The asterisk indicates this is a NOT (active low) signal.
• CONTINUED
9
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RC-28S/RC-24 Service Manual SORVALL® Centrifuges
Supplement
Table 2. Drive Control Module Signal Descriptions
(continued)
Signal Description
FULL CHOP* Originates at the control console. Full chop is selected when
this signal is in a logic low state. The term full chop refers to
method used for modulating the output bridge. As the motor is
commutated. the standard practice is to modulate either three
or all six of the power transistors used in the output bridge.
When full chop is selected, all six transistors are modulated.
BRAKE EN- Originates at the control console. The brake enable mode is
ABLE* selected when this signal is in a logic low state and the FOR¬
WARD ENABLE* signal is in a logic high state. When the Drive
is commanded to brake and no faults exist, the motor will de¬
celerate. If both a BRAKE ENABLE* signal and a FORWARD
ENABLE* signal are commanded at the same time, the Drive is
not enabled.
MOTOR A separate +5 Vdc supply input pin for exclusive use by the
TEMP+ temperature sensor located in the motor.
MOTOR The return path for the electrical current signal from the temp-
TEMP- erature sensor located in the motor.
"The asterisk indicates this is a NOT (active low) signal.
c. Drive System Performance
Following is a basic description of some of the operating parameters which should provide
a further understanding of the total system performance. The system consists of the
brushless dc motor drive and control, along with the motor.
Operating Voltages on High Voltage dc Bus (acceleration)
During a standby condition with a nominal 220 Vac-RMS power supplied to the drive
power input, the internal high voltage dc supply bus will be approximately at 305 Vdc.
With a nominal 208 Vac-RMS power applied to the drive power input, the internal high
voltage dc supply bus will be approximately at 288 Vdc. This voltage is unregulated and
may fluctuate with varying ac line conditions. It is also influenced by the centrifuge load
profile, meaning both the type of rotor selected and the speed at which it is rotating. In
general, high speed and larger rotors equate to a somewhat reduced dc bus voltage,
especially during rotor acceleration.
Operating Voltages on High Voltage dc Bus (deceleration)
During deceleration, the high voltage dc supply voltage may temporarily rise to as high as
385 Vdc. This occurs due to an effect called regeneration. Regeneration is the process of
converting the kinetic energy contained by the centrifuge rotor back to potential energy
10
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SORVALL® Centrifuges RC-28S/RC-24 Service Manual
Supplement
stored In the capacitors in the Drive Control Module. During the regeneration process, the
motor in effect reverses roles and functions as a generator by converting mechanical energy
to electrical energy. Under most high operating speeds with various rotor loads, it is not
practical to store all of the regenerated energy returned back to the Drive. Therefore, the
energy must be consumed in some other fashion. This is accomplished by converting the
potential energy to heat energy.
The Drive uses a circuit called a shunt regulator to bum off this excess energy as heat.
This circuit consists of basically a transistor switch and a brake resistor (Calrod) acting
as a shunt. The brake resistor is located external to the drive within the centrifuge. To
consume the excess potential energy from the capacitors requires that the shunt resistor
be switched ON and OFF across the high voltage dc supply bus. Whenever the voltage rises
above a nominal 376 Vdc. the shunt is switched ON. As the voltage falls due to the loading
effect of the brake resistor, it is switched OFF at a nominal 366 Vdc. The brake resistor
has a nominal resistance between 10 and 12 ohms.
ac Input Current
When the Drive is initially powered up there will be a short power surge to charge the
internal high voltage power supply capacitors. This results in a peak current pulse during
power up of approximately 35 amps from the ac supply line during the first few ac line
cycles. This pulse may be noted to exponentially decay over four or five complete cycles
of the ac line power. These capacitors should be fully charged with the Drive ready to run
in less than five seconds after initial ac power is applied.
When accelerating the largest rotors, peak ac current sourced to the drive may reach 45
amps, with an RMS equivalent up to 20 amps. Because the dc power used within the Drive
is derived from full wave rectified ac off the line, ac current sourced into the Drive tends
to appear like a clipped sinusoid. This waveshape is referred to as a haversine. The
haversine current conduction angle will vary as a percentage of the total ac line voltage
waveform, and the peak of this haversine current will rise and fall as the centrifuge load
profile changes. In general, the higher the power demand by the centrifuge, the larger the
haversine current pulse.
Motor Current Control
The Drive senses motor current delivery through two contactless Hall effect current
sensors. These devices are conditioned through internal circuitry inside the drive to
provide an average current balance of within 5%, phase to phase, over the delivery range
of 250 milliamperes to 20 amperes.
The average output current delivered to the motor is commanded by the control console.
It has the ability to resolve this control signal, passed to the Drive by way of the REF PWM'"
interface pin, to 1 part out of 1024. This means that, in theory, it can command average
current In increments of 20 milliamperes. In actual practice, the motor needs a minimum
of 250 milliamperes to effect some rotation.
Actual average current control accuracy is approximately ± 5% over the range of 250
milliamperes to 20 amperes. These figures of merit should be valid over the temperature
range of 10°C to 50°C.
11
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RC-28S/RC-24 Service Manual SORVALL® Centrifuges
Supplement
Internal Operating Temperatures
The Drive uses forced air cooling to maintain low operating temperatures within the
chassis for high reliability and long life. The overtemperature projection built into the
Drive consists of two independent temperature sensors. One sensbr is mounted on the
power transistor heatsirik used for the output bridge. The second sensor is mounted on
the Logic Interface P. C. Board. Both sensor signals are used to safely shutdown the drive
should operating temperatures become unreasonably high. The sensor on the heatsink
is set to trip at a nominal 88°C.
Under normal operating conditions, these sensors should never effect a shutdown. If,
however, the exhaust port for the air moving through the Drive should become blocked or
should the fan malfunction, internal temperatures may rise to a level causing an
overtemperature fault, which will cause a shutdown.
Normal heatsink temperature should be below 84°C when the combined conditions of both
high ambient air temperature and high power delivery to the motor occur.
Acoustical Noise
The Drive is designed to operate quietly- However, when operating at high power levels.
such as during high acceleration rates and high braking rates, some acoustical noise may
be heard. The audibility of this noise may produce a buzzing sound to the listener when
the side cabinet panels are off the centrifuge. This is normal and Is caused by the
magnetostriction effects of the magnetics within the Drive.
-
SORVALL® Centrifuges RC-28S/RC-24 Service Manual
Supplement
• small enclosure openings to limit finger access;
• printed circuit board trace spacings of at least 0.095 mm to ensure good over
surface insulation; and
• line side insulation sufficient to withstand 1500 volt.
Since the autotransformer is the main heat source, it is mounted outside the enclosure
and spaced away with mounting nuts (used as spacers). It radiates to the lower deck air,
minimizing the heating of internal enclosure components.
The heating and cooling solenoids are highly inductive. SP2210 relays are used to handle
such a low power factor load.
A special safety feature is the drive power presence sensing. A schmidt trigger optoisolator
is used to sense the presence of drive motor power, selected by relay K8, and convert to
a logic level square wave for transmission back to the controller. The controller then knows
that K8 is functional - tested at software startup in case of safety shutdown should the
drive not respond to a logic level OFF command in forward or should braking be stuck on
in the braking mode. This function gives a testable drive power shutdown to software
should logic level commands be Inoperative.
Because the optoisolator output is connected to the input of a nonmaskable processor
interrupt, there is uncertainty at startup. A schmidt trigger gate is used to inhibit the
compressor and drive motor feed power relays at power up. A few second delay ensures
that these outputs stay off. With drive feed off, the power present sensing is off, holding
the Interrupt line off, allowing the processor to complete its startup sequence.
TO CONTROLLER
P.C. BOARD
POWER
CONTROL
[^
1
20
3
16
5
7
9
11
13
15
17
19
J31
1
2
3
4
5
6
7
8
DRIVE CONTROL'
nc
VAC REL'
. LED SUPPLY
VAC ON-
LOCK DOOR-
COMPRESSOR ON-
HEAT'
. COOL'
. VACUUM BALLAST-
DRIVE MOTOR'
. OVREF
DRIVE POWER RETURN
DRIVE CONTROL FEED
nc(key)
DRIVE MOTOR FEED /
PROCESSOR P.S. FEED
PROCESSOR P.S. RETURN
COMPRESSOR FEED
. COMPRESSOR RETURN
POWER
DISTRIBUTION
BOX
["J30] HVacIN NEUTRAL /".
A0^
B0^ \>*
[JH] VAC/H.G. BYPASS ,,
\ i "c
^a 3 .24 V-/^
acRETURN „.'
VACUUM BALLAST ^'
COOL SOLENOID -
HEAT SOLENOID )
MOTOR FAN/DRIVE )
VACUUM REL SOL. /
DOOR LOCK ),, \ la
"The asterisk indicates this is a NOT (active low) signal.
Figure 4. Power Distribution Box Input/Output
13
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RC-28S/RC-24 Service Manual
Supplement
SORVALL® Centrifuges
e. Electronic System Glossary
Refer to Table 3 (below) In place of Table 3-6 (in Section 3 of the Service Manual).
Table 3. Electronic System Glossary
Code Origin Description
ABMINSPD
ACMON*
AIR TEMP IN
Drive Control Module
J33-7
U42-8 Controller P. C.
Board
Air Temperature
Sensor
AIR TEMP OUT U8-15 Controller P.C.
Board
AIR TEMP SEL U23-16 Controller
P. C. Board
BRAKE ENABLE* Drive Control Module
J33-11
BRIDGE
ENABLED*
CAUB*
Drive Control Module
J33-3
U15-12HostP. C.
Board
COMPRESSOR U52-9 Controller
ON* P. C. Board
COOL* U52-5 Controller
P. C. Board
DVEnab*/HOST U7-16 Host P. C.
ENABLE* Board
ABOVE MINIMUM SPEED. Back
EMF-derived independent tacho¬
meter check.
AC MONITOR. Tests the ac power
relay on the drive for proper opera¬
tion at start of every run.
AIR TEMPERATURE INPUT.
Input from air temperature sensor.
AIR TEMPERATURE OUTPUT. Scan
signal from computer to read air
temperature.
AIR TEMPERATURE SELECT Input
select to read data from air tempera¬
ture sensor.
Enables drive for braking action
(active low).
Drive control status back to Control¬
ler.
Calibrate command to URR
P. C. Board.
COMPRESSOR ON. Energizes
solid state relay which provides
208 Vac to compressor.
COOL. Energizes solid state relay
K4 to energize cooling solenoid.
Independent Host drive enable signal
so either Host or Controller can over¬
ride the other and shut drive down.
Denab* U7-12 Host P. C. Board LCID display enable signal.
'The asterisk indicates this is a NOT (active low) signal. (CONTINUED)
14
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RC-28S/RC-24 Service Manual
Supplement
SORVALL® Centrifuges
Table 3. Electronic System Glossary (continued)
Code Origin Description
DIR
DOOR CLOSED
DOOR LOCKED
DOOR OPEN
DOOR
SOLENOID
DOWN*
DRIVER-
DRIVE AC
ENABLE
DXHOME
EOTV*
EXTERNAL
POWER +5VDC
EXTERNAL
COMMON
FORWARD
ENABLE*
FORWARD
ENABLE
POWER
U8-4 URR P. C.
Board
Microswitch on door
stop
Hall effect switch on
latch
Microswitch on door
stop
K3-1
U15-4URRP. C.
Board
U52-18 Controller
P. C. Board
Power Distribution
Box,J2-l
U6-8 Host P. C.
Board
U21-4 URR P. C.
Board
Drive Control Module
J-33, Pins 2. 8, 10.
12. and 16
Drive Control Module
J-33, Pins 4. 18 and 20
Drive Control Module
J33-5
Drive Control Module
J33-6
Signal advising Host direction of
door movement.
Door closed signal.
DOOR IS LOCKED. Door is fully
closed and door solenoid has de-
energized to lock door.
DOOR IS OPEN. Door has opened
far enough to trip door open switch.
DOOR SOLENOID, dc return for
door solenoid.
Down count from door position
system.
DRIVE POWER ENABLE. Energizes
solid state relay which supplies Drive
Control Module with 208 V.
Enables ac to the Drive Control
Module.
DOOR IS IN HOME POSITION.
When door is fully open. this
signal is high.
Pulse from URR advising that
URR data is complete and can
be processed for recognition.
+5 volt supply to Drive optoisola-
tors.
Ground return for Drive optoisola-
tors.
Enables drive for forward motion.
Separate power for forward command
optoisolator.
'The asterisk indicates this is a NOT (active low) signal. (CONTINUED) -1
15
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RC-28S/RC-24 Service Manual
Supplement
SORVALL® Centrifuges
Table 3. Electronic System Glossary (continued)
Code Origin Description
FULL CHOP*
HEAT*
HGBV^l
HGBV#2
IDEnab*
IDGate*
IMBALANCE
InitCt*
InitG*
JMPR SEL
JMPRTEMP
OUT
Jumper TEMP
SEL
LCDE
Drive Control Module
J33-9
U52-7 Controller
P. C. Board
K4-1
K5-1
U 15-10 Host P. C.
Board
U22-4URRP.C.
Board
Imbalance Detector
Ul 1-8 Host P. C.
Board
U9-4 URR P.C.
Board
U23-18 Controller
P. C. Board
U8-6 Controller
P. C. Board
U6-17 Controller
P. C. Board
U10-4 Host P. C.
Board
HALF OR FULL CHOP. Half chop
during normal acceleration and run;
full chop for rate control to MOSFET
drivers.
HEAT. Energizes solid state relay
K5 to energize hot gas solenoid.
HOT GAS BYPASS VALVE # 1. dc
return for hot gas valve #1.
HOT GAS BYPASS VALVE #2. dc
return for hot gas valve #2.
Signal advising URR Board that
initial count is complete and to now
count shaft encoder pulses.
Range pulse. Pulse width tells Host
result of the ultrasonic interrogation.
Imbalanced rotor.
Pulses to URR to calibrate X position
to center interrogate map over rotor
and drive.
First up count after door leaves
DxHome switch toggles this line.
telling Host it is time to send X offset
initial count pulses.
JUMPER TEMPERATURE SELECT.
Input select to read data from
jumper temperature sensor.
JUMPER TEMPERATURE OUTPUT.
Scan pulse from computer to read
juniper temperature.
Selects Jumper temperature
sensor.
Chip select signal for the 2 x 40
LCD display module.
"The asterisk indicates this is a NOT (active low) signal. (CONTINUED)
16
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SORVALL® Centrifuges RC-28S/RC-24 Service Manual
Supplement
Table 3. Electronic System Glossary (continued)
Code Origin Description
LDEN*
LOCK DOOR*
U24-13 ControUer
P. C. Board
U52-12 ControUer
P. C. Board
MOTOR TEMP+ Drive Control Module
J33-13
MOTOR TEMP- Drive Control Module
J33-14
PROMOUT O*
PROMOUTI*
REFFWM*
SHUNT ACTIVE
Step*
SUP*
TACH INPUT
UP*
VAC ON*
VAC PUMP*
U25-11URRP. C.
Board
U25-12URRP. C.
Board
U38-16 ControUer
P. C. Board
Drive Control Module
J33-15
U12-4URRP.C.
Board
U27F-12URRP.C.
Board
Drive Control Module
J33-19
U14B-4URRP. C.
Board
U52-14 ControUer
P. C. Board
Kl-1
'The asterisk indicates this is a NOT (active low) signal.
LOAD ENABLE. Allows loading new
divisor in tachometer count chain.
LOCK DOOR Energizes solid state
relay K3 to energize rotary door
solenoid.
MOTOR TEMPERATURE INPUT.
Input voltage from motor tempera¬
ture sensor.
MOTOR TEMPERATURE OUTPUT.
Return path for voltage from motor
temperature sensor.
Interrogate trigger to range measure¬
ment circuits.
Initiates EOTV* signal when door
almost closed.
Reference pulse width modulated
motor current demand to Drive
Control Module.
Indicates brake activity.
Signal advising Host that door has
reached a URR interrogation point.
SWITCHED UP COUNT. Sometimes
carries Initial count; sometimes up
count from door position system.
Tachometer input from motor.
Up count from door position
system.
Energizes relay Kl to turn on vacuum
pump and hot gas bypass solenoid.
VACUUM PUMP. ac return for
vacuum pump motor and hot gas by¬
pass solenoid.
(CONTINUED) -'
17
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RC-28S/RC-24 Service Manual
Supplement
SORVALL® Centrifuges
Table 3. Electronic System Glossary (continued)
Code
VAC REL*
VAC SOLENOID
VACUUM
BALLAST-
VACUUM
LEVEL
WBG
WBG-TST-
HIGH
WBG-TEST-
LOW
WDOG
STROBE
Origin
U52-16ControUer
P. C. Board
K2-1
U52-3 ControUer
P. C. Board
Vacuum Sensor
P. C. Board
Q7 ControUer
P. C. Board
U24-16 ControUer
P. C. Board
U24-15 ControUer
P. C. Board
U47-19 ControUer
P. C. Board
Description
VAC RELEASE ENABLE. Energizes
solid state relay K2 to open vacuum
release solenoid.
Vacuum solenoid dc return for
vacuum solenoid.
Signal to activate vacuum
baUast.
Vacuum level input voltage
(0 to 1 volt fuU scale).
Emergency shutdown signal.
Signal for automatic test of
emergency shutdown circuit.
Signal for automatic test of
emergency shutdown circuit.
Watchdog strobe.
•The asterisk indicates this is a NOT (active low) signal.
Part 4: Repair and Replacement
a/ways wdiit,]pEwrm»iM^^^
a;re^ch
-
SORVALL® Centrifuges RC-28S/RC-24 Service Manual
Supplement
a. Relay Printed Circuit Board Replacement
NOTE
Use this procedure in place of the procedure in the Service Manual, Section
4, paragraph 4-8.
CAUTION
Read paragraph 4-1 (Service Manual, Section 4), Precautions for Proper
Handling of Printed Circuit Boards, before you begin this procedure.
Paragraph 4*1 contains important information regarding how to prevent
injury and/or damage to printed circuit board components.
Replace the Relay P. C. Board (PN 59745):
1. Turn the centrifuge power OFF, and unplug the power cord.
2. Remove the centrifuge front and right-side cabinet panels.
3. Disconnect all plugs from the top of the Power Distribution Box.
4. Remove the Power Distribution Box mounting screw from the rear of the box, and
remove the box from the centrifuge. Place the box on a clean, flat work surface.
5. Turn the 1/4-turn fastener on the right side of the Power Distribution Box coun¬
terclockwise, and remove the panel from the box.
6. Disconnect plug P6 from the Relay P. C. Board.
7. Remove the Relay P. C. Board from inside the Power Distribution Box: push the tab
on the four fasteners (one in each comer of the board), and carefully pull the board
off the fasteners.
8. Position the new board inside the Power Distribution Box, connector side first - the
connectors go through the slot inside the box.
9. Push the board onto the four comer fasteners to secure the board in place.
10. Plug P6 into the Relay P. C. Board
11. Reinstall the panel on the Power Distribution Box. Turn the 1 /4-tum fastener on the
side of the box clockwise to secure the panel in place.
12. Reinstall the Power Distribution Box in the centrifuge, and secure it in place using the
screw removed in Step 4.
13. Reconnect all plugs to the top of the Power Distribution Box.
14. Reinstall the front and right-side cabinet panels.
19
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RC-28S/RC-24 Service Manual SORVALL® Centrifuges
Supplement
b. Circuit Breaker/Fuse Switch Replacement
NOTE
Use this procedure in place of the procedure in the Service Manual, Section
4, paragraph 4-11.
There are two circuit breakers (drive and compressor) and three fuse switches located
inside the Power Distribution Box (see Part 8, figure 66). Both circuit breakers are PN
90551, and all three fuse switches are PN 90565. Replace as follows:
1. Remove and disassemble the Power Distribution Box (see procedure a. Relay P. C.
Board Replacement. Steps 1 through 5).
2. Remove the Relay P. C. Board mounting plate (with Relay Board) by removing the three
screws that are holding it in place. Carefully place the plate and board assembly aside
so it will be out of the way for the remainder of the procedure.
3. Disconnect the wires from the circuit breaker or fuse switch being replaced. Make a
note of their orientation for reassembly.
4. Remove the circuit breaker or fuse switch:
• circuit breaker: remove the two screws from the outside of that box that hold the
breaker in place and remove the breaker;
• fuse switch: unscrew the fuse switch locking nut from outside the Power
Distribution Box and remove the switch; if the fuse is still good, remove it from
the switch and reinstall it in step 5.
5. Install new circuit breaker or fuse switch:
• circuit breaker: place the new breaker in position, and secure it in place using
the screws removed in Step 4.
• fuse switch: install the proper fuse in the fuse switch, then install the fuse switch
and tighten the locking nut to secure switch in place.
6. Reconnect all wires that were disconnected in Step 3.
7. Reassemble Power Distribution Box, reinstall it in the centrifuge and secure in place.
8. Reconnect all plugs to the top of the Power Distribution Box.
9. Reinstall the front and right-side cabinet panels.
c. Solid State Relay (Drive & Compressor) Replacement
NOTE
Use this procedure in place of the procedure in the Service Manual, Section
4, paragraph 4-12.
20
-
SORVALL® Centrifuges RC-28S/RC-24 Service Manual
Supplement
Two solid state relays (drive and compressor) are located inside the Power Distribution
Box; both relays are PN 69602. Refer to Part 8. figure 66 and replace the relay(s).
1. Remove and disassemble the Power Distribution Box (see procedure a. Relay P. C.
Board Replacement. Steps 1 through 5).
2. Remove the Relay P. C. Board mounting plate (with Relay Board) by removing the three
screws that are holding it in place. Carefully place the plate and board assembly aside
so it will be out of the way for the remainder of the procedure.
3. Disconnect the wires from the relay being replaced. Make a note of their orientation
for reassembly (see label on side of relay).
4. Remove the two relay mounting nuts (with lockwasher and flatwasher). Remove relay.
5. Apply thermal compound to the bottom of the relay, then position the new relay in
place and secure it with the mounting nuts and washers removed in Step 4.
6. Reconnect all wires that were disconnected in Step 3.
7. Reassemble the Power Distribution Box. Reinstall the box in the centrifuge and secure
it in place.
8. Reconnect all plugs to the top of the Power Distribution Box.
9. Reinstall the front and right-side cabinet panels.
d. Changing the Vacuum Pump Oil (RC-28S Only)
NOTE
The procedure to change the vacuum pump oil is the same as the one in the
Service Manual, Section 4, paragraph 4-33, except as noted below.
• Change Step 8 to read:
Cut the nylon cable tie securing the vacuum pump drain line to the wiring harness.
• Change Step 16 to read:
Position the tubing clamp in place on the drain line. Close the clamp and tighten it
securely to seal the drain line. Secure the vacuumpump drain line to the wiring harness
using the nylon cable tie supplied.
• Replace figure 4-28 with figure 5.
e. Drive Motor Replacement
NOTE
Use this procedure in place of the procedure in the Service Manual, Section
4, paragraph 4-35.
1. Turn the centrifuge power ON and open the chamber door.
21
-
RC-28S/RC-24 Service Manual
Supplement
SORVALL® Centrifuges
Figure 5. Parts Identification, Vacuum Pump Oil Change
22
-
SORVALL® Centrifuges RC-28S/RC-24 Service Manual
Supplement
2. Turn the centrifuge power OFF and unplug the power cord.
lliBB^^^^^^^^^^^
lliniisjptt^
||oentnfuge,|||y^ four minutes centrifuge
^pOIBWl^
inside the Drive Control Module that store a significant amount of energy.
^Tliese^capaci^^
|Fk»w^titslft]^
jii^SultlJitt^Mri^
3. Remove the front and right side cabinet panels.
4. Insert a 4 nun Alien wrench in centerhole on top of tapered drive spindle and loosen
screw by turning it counterclockwise. Pull the drive spindle off the drive shaft.
5. Using a 3 mm Alien wrench, remove the four outermost screws from heat shield in
bottom of chamber. Then using a 2.5 mm Alien wrench, remove the other four screws
from around centerhole of heat shield. Remove heat shield and heat transfer gasket.
6. Lift temperature sensor assembly off the motor shaft and set it aside out of the way.
7. Using a thin screwdriver with long shaft, carefully pry the doughnut 0-ring from
around the motor.
8. Remove both halves of dampening ring from around the motor. If they don't come out
easily, use one of the heat shield screws: thread screw into tapped insert in dampening
ring; pull up on screw to remove ring. then remove screw from ring.
9. Reinstall the tapered drive spindle on the drive shaft.
CAUTION
The tapered spindle is used to pull the drive motor from the centrifuge so
be sure it is fastened tightly to drive shaft.
10. Disconnect all plugs from the top of the Power Distribution Box.
11. Remove the Power Distribution Box mounting screw from the rear of the box. and
remove the box from the centrifuge. Place the box on a clean, flat work surface.
12. Make swrefourrnirvutes have elapsed since the powerwas turned OFF. then disconnect
the following plugs- in the order listed-from the Drive Control Module: P32, P34. P33,
andP9.
13. Using a 5 mmAllen wrench, remove the four screws holding the Drive Control Module
in place. Remove the module from the centrifuge.
23
-
RC-28S/RC-24 Service Manual
Supplement
SORVALL® Centrifuges
TAPERED
SPINDLE
SPINDLE
SCREW
EVAPORATOR
SEAL 0-RING
EVAPORATOR
HOI-DOWN
RING
0-RING,
SENSOR
LEAD
DAMPING
RING
HEAT SHIELD
HEAT
TRANSFER
GASKET
EVAPORATOR
ASSEMBLY
DETECTOR
ADJUSTMENT
SCREW
LOCKWASHER
LARGE NUT
28 mm (1 1/8 in.)
Figure 6. Parts Location, Drive Motor Replacement
24
-
SORVALL® Centrifuges RC-28S/RC-24 Service Manual
Supplement
14. Open Velcro® fastener in vinyl cover around motor fan housing: remove vinyl cover.
15. Remove the motor ground wire (with two lockwashers) from the base of the frame, left
of the motor housing.
16. Using a 28 mm (1-1/8 inch) wrench, remove the large nut (with lockwasher and
washer) from the threaded gimbal post.
17. Lift the motor out of the centrifuge. Carefully guide the cables through the motor
housing. Lay the motor on a clean work surface.
CAUTION
Do not drop motor; do not expose it to temperatures above 120°C; and do
not lay it near metal objects. The motor is highly magnetic and heat or metal
objects can damage it.
18. Insert a 4 mm Alien wrench in centerhole on top of tapered drive spindle and loosen
screw by turning it counterclockwise. Pull the drive spindle off the drive shaft.
19. Remove the gimbal assembly from the old motor:
a. Using the spanner wrench (or a strap wrench), unscrew the gimbal (clockwise)
and slide it off threaded gimbal post.
b. Unscrew (counterclockwise) the threaded gimbal post from the motor and remove
it from the motor.
20. Apply a light coat of antigalling grease (PN 61556) to the threaded surfaces of the
gimbal assembly, then Install both pieces of the gimbal assembly on the new motor.
21. Place tapered spindle on new motor, and tighten the screw in centerhole to secure the
spindle to the drive shaft.
22. Hold new motor assembly over the opening in chamber and rotate it so that the magnet
on the side of the motor Is aligned with imbalance detector and the cables on bottom
of motor are aligned over holes in motor housing (see Service Manual, Section 4, figure
4-31). Carefully guide motor cables through motor housing and lower motor in place.
CAUTION
Be careful not to pinch any of the motor harness between the gimbal and
the motor housing.
23. Insert a 4 mm Alien wrench in centerhole on top of tapered drive spindle and loosen
screw by turning it counterclockwise. Pull the drive spindle off the drive shaft.
24. Check the alignment to the Imbalance detector: reach through the imbalance detector
slot at the top rear of motor housing and pinch sides of the imbalance detector and
motor rib simultaneously — they are approximately the same width, therefore.
pinching them together will cause magnet to align perfectly with the detector.
25. Place the nut. lockwasher. and washer removed in Step 16 on the threaded gimbal
post. Tighten the nut to 68 N»m (50 ft. Ibs) to secure the motor to the motor housing.
25
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RC-28S/RC-24 Service Manual SORVALL® Centrifuges
Supplement
26. Reconnect the motor ground wire (with lockwashers).
27. Wrap the vinyl cover around the motor fan housing, being careful to keep the two
motor cables separated, and close the Velcro® fastener.
NOTE
Do not tie the ribbon cable to the motor wires. To do so will cause an
increase in inductive electrical noise to the control electronics, resulting in
intermittent faults.
28. Position the Drive Control Module in place and secure it in place using the screws
removed in Step 13.
29. Reconnect plugs to the Drive Control Module in order. P9, P33, P34, and P32.
30. Reinstall the Power Distribution Box in the centrifuge and secure it in place using the
screw removed in Step 11.
31. Reconnect all plugs to the top of the Power Distribution Box.
32. Push both halves of the dampening ring in place around the motor until they are
seated against motor.
33. Clean doughnut 0-rlng and apply alight coat of vacuum grease to it. Place 0-ring
around the drive.
34. Slide the temperature sensor assembly back on the motor shaft.
35. Position heat transfer gasket in place (if damaged, replace with a new one PN 59618),
then align the four holes near the centerhole of the heat shield with the four holes in
the temperature sensor. Secure heat shield to temperature sensor with the four
screws removed in Step 5.
36. Rotate the heat shield to align the four outer holes in the heat shield with the holes
in the evaporator holddown ring; make sure the heat transfer gasket does not
protrude. Secure heat shield in place with the other four screws removed in Step 5.
37. Clean the end of the drive shaft and the inner area of the tapered spindle with acetone
or alcohol.
CAUTION
The drive shaft and tapered spindle must be clean. If they are not clean,
slippage will occur between the drive shaft and the tapered spindle,
possibly damaging the shaft or the spindle, or both.
NOTE
Before installing drive spindle, apply two drops of Loctite® 222 or 242
adhesive to threads inside shaft; be very careful not to get LOCTITE on
surfaces outside of threaded area.
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38. Install tapered drive spindle. Make sure the spindle is fully seated on the shaft, then
tighten the screw in the top of the spindle to secure it to the drive shaft.
39. Reinstall the right-side and front cabinet panels.
40. Plug in the power cord and turn centrifuge power ON.
41. Perform all necessary calibrations; see Service Manual. Section 8, Table 8-3.
42. RC-28S only. Conduct a run with a SUPRAspeed9 rotor and monitor vacuum level
in DIAGNOSTICS (Screen 1, User-1. #1). Verify that centrifuge pulls a vacuum ^ 2
mbar. If a SUPRAspeed® rotor is not available, check vacuum level using DIAG¬
NOSTICS, Screen 3, Serv-2. #9 and follow display prompts.
43. Use highest speed rotor available that is intended for use in the centrifuge, and
conduct a test run to maximum speed of the rotor; verify that rotor reaches top speed.
f. Drive Motor Fan Replacement
The procedure to replace the drive motor fan is the same as the one in Section 4, paragraph
4-36 with the following exception: do not remove the Power Distribution Box; remove the
Drive Control Module instead.
g. Drive Control Module Replacement
Following is the replacement procedure for the new Drive Control Module, PN 59752:
1, Turn the centrifuge power OFF, and unplug the power cord.
IBIIBMi^^^^^^^^^
^^^
| Tliere^arech^^ the Drive Control Module that store a
significant amount of energy. These capacitors remain elertncally cner-?
gized for four minutes after the power is turned OFF. Failure to Wait four
'Imfiiuliiesl^canTesuft
2. Remove the front and both side cabinet panels from the centrifuge.
3. Make sure Jbw minutes have elapsed since the power was turned OFF. then disconnect
plugs, in the order listed, from the Drive Control Module: P32, P34. P33, and P9.
4. Using a 5 mm Alien wrench, remove the four screws holding the module in place.
Remove the module.
5. Position the new Drive Control Module in place and secure it in place using the screws
removed in Step 4.
6. Reconnect plugs to the Drive Control Module in order P9. P33. P34, and P32.
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RC-28S/RC-24 Service Manual SORVALL® Centrifuges
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NOTE
Do not tie the ribbon cable to the motor wires. To do so will cause an
increase in inductive electrical noise to the control electronics, resulting in
intermittent faults.
7. Reinstall all cabinet panels. Plug in the centrifuge power cord.
8. Perform all necessary calibrations; see Service Manual. Section 8. Table 8-3.
Part 5: Diagnostics &. Fault Troubleshooting
a. Screen 1, Fault Messages
NOTE
Four new fault messages have been added: Bad AC Power Relay, Bad Brake
Monitor Circuit, Bad Min Speed Monitor, and Calrod Overtemp (described
below). Flow charts for these faults are included in this supplement. In
addition, several flow charts from Section 5 of the Service Manual have
been revised for use with RC-28S centrifuges S/N 9002294 & above and
all RC-24 centrifuges; the revised flow charts are also included. See list of
new/revised flow charts below and on next page.
Following is a description of the four new fault messages:
Bad AC Power Relay. Refrigeration System fault that occurs if the ac power relay that
supplies power to the Drive Control Module is not working. See figure 7.
Bad Brake Monitor Circuit, Drive System fault. The PWM signal from the Calrod
shunt is multiplexed, filtered, then converted to a digital voltage. This fault occurs if
the voltage is not at the correct level. See figure 8.
Bad Min Speed Monitor. Drive System, Bridge fault. This fault checks for a failed
tachometer. ABMINSPD is active high when rotor speed if greater than 2000 rpm. and
it is active low when rotor speed is less than 1000 rpm. The fault occurs if tachometer
reads 0 rpm and rotor is coasting at a high speed. See figure 10.
Calrod Overtemperature. An Overspeed System fault that occurs when the brake
resistor heating element has the full 208 volts across it. If the braking FET shorts out,
it can place line voltage across the brake heating element (Calrod), causing it to get
extremely hot and present a fire hazard. See figure 12.
Following is a complete alphabetical list of the fault messages that have new or revised flow
charts (the flow charts are figure 7 through 53). If the fault message does not appear in
this list, use the flow chart in Section 5 of the Service Manual.
Bad AC Power Relay Calrod Overtemp Door Not Latched
Bad Brake Monitor Circuit Can't Reach Full Vacuum Door Not Locked
Bad Drive Accel Ctrlr Drive Enable Out Door Open Switch
Bad Min Speed Monitor Door Locked Switch Drive Enable (Ctrlr Off)
Bad Speed Control Door Not Closed Drive Enable ( H & C Off)
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SORVALL® Centrifuges
Drive Enable (Host Off)
Drive Failed to Start
Drive Still Enabled
Dv-Enab FALSE Refused
Dv-Enab TRUE Refused
High Chamber Temp
High Drive Temperature
Improbable Speed Chng
Inertia Out of Range
Inertia Too High
Inertia Too Low
Inoperable Vacuum
Instrument Overspeed
Loss of Tachometer
Low Chamber Temp
No Ctrlr Drive Disable
No Ctrlr Drive Enable
No Decel Detected
No Door Unlock
No Drive Enable (H & C)
Open Winding Sensor
RC-28S/RC-24 Service Manual
Supplement
Rotor Overspeed
Rotor Overtemp
Shorted Winding Sensor
Speed Overshoot Trap
Temp Out of Range
Vacuum Loss
Vacuum Release Failure
Warn-Marginal Vacuum
Warning-Hot Gas Failed
Warning-Low Accel
Warning Poor Brake
b. Screen 2, User DIAGNOSTICS
The following changes have been made to Screen 2. User DIAGNOSTICS (refer to Service
Manual, Section 5, Table 5-2):
• User-1 routines #21 through #25 are no longer used
• User-1 #31 was changed from Bridge Current Sense (A) to Shunt Active Sense (see
description below)
31 Shunt Active Sense Type: Monitor
Monitors the filter output for SHUNT_ACTIVE. The range is from 0 to 5 volts, where
5 volts is normal. If reading is less than 0.5 volts, there is a short across the Calrod.
Should read 5 volts at all times except during braking with the brake ON, in which case
it should read from 3 to 5 volts. If reading indicates much less than 5 volts, there is
a problem and the Calrod Overtempeture fault will occur.
• Replace the description of User-1 # 32. HES Offset, with the following:
32 HES Offset Type: Monitor
The value displayed remains constant at 36; its onlypurposeis to indicate the current
HES Offset.
c. Screen 3, Service DIAGNOSTICS
The following change has been made to Screen 3, Service DIAGNOSTICS (refer to Service
Manual. Section 5. Table 5-9):
• Serv-2 #24 was changed from Temp Offset Coeff to Lock A/D on Shunt Active (see
description below)
24 Lock A/D on Shunt Active Type: Override
Causes the Controller P. C. Board to display only the SHUNT_ACTIVE input and to
ignore the other sensor inputs.
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Catastrophic fault. Clears when centrifuge power is turned OFF.
Figure 7. Bad AC Power Relay
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Catastrophic fault. Clears when centrifuge power is turned OFF.
Figwe8. Bad Brake Monitor Circuit
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SORVALL® Centrifuges
FAULT: Bad Drive Accel
See figure 23 (FAULT:
Drive Failed to Start).
Nonrecoverable fault. Clears at zero setspeed.
Figure 9. Bad Drive Accel
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Catastrophic fault. Clears when centrifuge power is turned OFF.
Figure 10. Bad Min Speed Monitor
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SORVALL® Centrifuges
FAULT: Bad Speed Control
See fig. 43 (FAULT:
Rotor Overspeed).
Nonrecoverable fault. Clears at zero setspeed.
Figure 11. Bad Speed Control
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Catastrophic fault. Clears when centrifuge power is turned off.
Figure 12. Calrod Overtemp
Rev. 7/93 37
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SORVALL® Centrifuges
FAULT: Cant Reach Full Vacuum
See figure 48
(FAULT: Vacuum Loss).
Nonrecoverable fault. Clears at start of next run.
Figure 13. Can't Reach Full Vacuum
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Nonrecoverable fault. Clears at zero setspecd.
Figure 14. Ctrlr Drive Enable Out
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Noairecoverable fault. Clears whesi switch configuration Is corrected.
Figure 15. Door Locked Switch
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Nonrecoverable fault. Clears at start of next run.
Figure 16. Door Not Closed
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SORVALL® Centrifuges
Nonrecoverable fault. Clears at start of next run.
Figure 17. Door Not Latched
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FAULT: Door Not Locked
See figure 17
(FAULT:Door Not
Latched).
Nonrecoverable fault. Clears at start of next run.
Figure 18. Door Not Locked
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SORVALL® Centrifuges
Nonrecovcrable fault. Clears when switch configuration is corrected.
Rgure 19. Door Open Switch
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Nonrecoverable fault. Clears at start of next run.
Figure 20. Drive Enable (Ctrlr off)
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SORVALL® Centrifuges
FAULT: Drive Enable (H & C off)
See figure 24
(FAULT: Drive Still
Enabled).
Nonrecoverable fault. Clears at start of next run.
Figure 21. Drive Enable (H & C off)
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FAULT: Drive Enable (Host off)
Turn centrifuge power ON, but
do not start a run. See if DS-3
on the Host PCB is ON.
Nonrecoverable fault. Clears at start of next run.
Figure 22. Drive Enable (Host off)
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Nonrecoverable fault. Clears at start of next run.
Figure 23a. Drive Failed to Start
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Nossrecoverable fault. Clears at start of next run.
Figure 23b. Drive Failed to Start
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Catastrophic fault. Clears when Host Reset and BRIDGE ENABLED* arc
cleared by the Controller P. C. Board (i.e., centrifuge power OFF).
Figure 24. Drive Still Enabled
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SORVALL® Centrifuges
FAULT: Dv Enab FALSE Refused
^
Unplug P10 from Ctrir PCB. Check rbn cbl from P10
on Ctrir PCB to P33 on DCM for opens and/or shorts.
Nonrecoverable fault. Clears at start of next run.
Figure 25. Du-Enab FALSE Refused
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FAULT: Dv Enab TRUE Refused
See figure 25 (FAULT:
Dv Enab FALSE
Refused).
Nonrecoverable fault. Clears at start of next run.
Figure 26. Dv-Enab TRUE Refused
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SORVALL® Centrifuges
Recoverable fault. Clears when Controller P. C. Board measures air and
base temperature
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SORVALL® Centrifuges RC-28S/RC-24 Service Manual
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Recoverable fault. Clears when motor winding temperature is
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RC-28S/RC-24 Service Manual
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SORVALL® Centrifuges
Catastrophic fault. Clears when Controller P.C. Board detects no brake,
no forward torque, and a speed of
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SORVALL® Centrifuges RC-28S/RC-24 Service Manual
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FAULT: Inertia Out of Range
See figure 31
(FAULT: Inertia
Too High).
Nonrecoverable fault. Clears at start of next run.
Figure 30. Inertia Out of Range
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Nonrecoverable fault. Clears at zero setspeed.
Figure 31. Inertia Too High
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FAULT: Inertia Too Low
See figure 31
(FAULT: Inertia
Too High).
Nonrccoverable fault. Clears at zero setspeed.
Figure 32. Inertia Too Low
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FAULT: Inoperable Vacuum
See figure 48 (FAULT:
Vacuum Loss).
Nonrecovcrable fault. Clears when vacuum pump turns OFF.
Figure 33. Inoperable Vacuum
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Nonrecoverable fault. Clears at zero setspeedc
Figure 34. Instrument Ouerspeed
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Catastrophic fauSt. Clears when Controller P.C. Board detects no brake, no forward torque, and a speed of
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FAULT: Low Chamber Temp
Perform a run to 2000 rpm using any rotor
intended tor use in RC-28S. Go to DIAG
Screen 2, User-1 #2. Turn monitor ON.
When DIAG screen displays 4°C, watch
U45-4 & U45-5 on Ctrlr PCB.
Recoverable fault. Clears when air temperature is > -20°C.
Figure 36. Low Chamber Temp
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SORVALL® Centrifuges
Check revision level of Host
PCB and Ctrir PCB to be
sure they are compatible.
Call Du Font for current
software information.
See fig. 24
FAULT: Drive
Still Enabled. •YES
Nonrecoverable fault. Clears at start of next run,
Figure 37. No Ctrlr Drive Disable
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Nonrecoverable fault. Clears at start of next run.
Figure 38. No Ctrlr Drive Enable
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SORVALL® Centrifuges
FAULT: No Decel Detected
Perform a run to 10 000 rpm
with Brake On. Press STOP and
watch U40-2 & U40-8 on Ctrlr
PCB. They should be OFF as
long as speed is >2000 rpm.
YES
Restart run. At set speed (10K),
press STOP and unplug P10
from Ctrlr PCB. Watch U40-2
& U40-8. They should be OFF
as long as speed is >2000 rpm.
Nonrecoverable fault. Clears at start of next run.
Figure39. No Decel Detected
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Nosirecoverable fault. Clears at start of next run.
S^ure 40. No Door Unlock
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Nonrccoverable fault. Clears at start of next run.
Rev. 7/93
Figure 41. No Drive Enable (H & C)
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FAULT: Open Winding Sensor
Check J21 on the Ctrir PCB.
Pins must be properly oriented
and there should be a jumper
across top 2 pins (PI & P16).
Install J21 so pins are properly
oriented. If top pins are not
jumpered, remove J21, rotate
it 180° and reinstall it.
Nonrecoverable fault. Clears when chamber door is opened.
Figure 42. Open Winding Sensor
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SORVALL® Centrifuges
Nonrecoverable fault. Clears at start of next run.
Figure 43. Rotor Ouerspeed
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FAULT: Rotor Overtemperature - Troubleshooting Procedure:
IMPORTANT: Before beginning to troubleshoot, note if the fault occurred during a
vacuum run. If so, when checking to see if fault reoccurs, first perform a pull-down run
at maximum air speed. If fault reoccurs, continue to troubleshoot. If fault does not
reoccur, perform a pull-down run at maximum vacuum speed. If fault reoccurs during
the vacuum run, troubleshoot the vacuum system.
Go To
Step Required Action & Evaluation Conclusion Step
1 Precool/preheat rotor in centrifuge being sure to reenter (rekey) desired Temp
and accept the Max default. Press START, go to D1AG, Screen 2, User-1, #2
and turn Monitor ON. Ctrlr Sample Temp should be within 2° of Set Temp in
30 minutes or less. Do temperatures equalize within 30 minutes? yes 2
no 3
2 Does fault reoccur? yes 3
no END
3 Visually check condenser. Is inlet blocked? yes 4
no 5
4 Clean condenser/clear blockage. Does fault reoccur? yes 5
no END
5 Perform A/D Channel 0 Check (Section 6, para. 6-2), and check Air and Jumper
Sensors using the Temperature Sensor Verification Check (Section 6, fig. 6-10).
Replace any faulty sensor. Does fault reoccur? yes 6
no END
6 Is REFRIGERATION CB (CB2) on PDB tripped? yes 7
no 13
7 Reset CB2 and perform a run @ 2000 rpm and-20°C. Does CB2 trip again? yes 8
no END
8 Press STOP and turn power OFF. Unplug P/J101 at compressor. Connect DMM
(set at lOOOVac scale) to J101-1 & J101-2. Turn power ON, restart run and check
DMM. Voltage (±10%) should be 230V for 60Hz, or 190-200V for 50Hz.
Is voltage correct? yes 10
no 9
Recoverable fault. Clears at start of next run or when START is pressed.
Figure 44. Rotor Overtemperature
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SORVALL® Centrifuges
Go To
Step Required Action & Evaluation Conclusion Step
9 Correct wiring at TB1 inside PDB as explained in Voltage Conversion (para. 2-3),
then restart run. Does CB2 trip again? yes 10
no END
10 Press STOP and reset CB2. Reconnect P/J101 (if not already reconnected) and
place DMM clamp-on device on one of the compressor wires. Set DMM for ac
amps and restart run. Is current 5A? yes
no
14 Visually check condenser fan. Is fan operating?
15 Check fan wiring, repair or replace fan as required. Does fault reoccur?
16 Check HEAT LED on PDB. Is it ON?
17 Charge Refrigeration System.
18 Check U45-5 on Ctrlr PCB. Is it ON?
19 Replace Relay PCB.
20 Press STOP and turn power OFF. Unplug P9 from Ctrlr PCB and turn power
back ON. Go to DIAG Screen 3, Serv-2 #3. Turn (Ovride) ON, press on/off
to de-energize Hot Gas Control Solenoid (HGBV 2). Did U45-5 go OFF?
21 Replace Ctrlr PCB.
22 Reconnect P9 to Crtir PCB, and unplug P2 from PDB. Is U45-5 still OFF?
yes
no
yes
no
yes
no
yes
no
yes
no
yes
no
11
12
END
END
14
24
16
15
16
END
18
38
END
20
19
END
22
21
END
19
23
Figure 44. Rotor Overtemperature (continued)
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Step Required Action & Evaluation
23 Replace rbn cbl from Ctrlr PCB (P/J9) to PDB (P/J2).
24 Check RFG CMPR LED on PDB. Is it ON?
25 Check for HVac at compressor connector P/J101. Is there high voltage?
26 Open between J101 at compressor and P31 -7/P31 -8 at PDB. Repair harness.
27 Check Cap Box. Is Cap Box OK?
28 Compressor problem. Replace compressor.
29 Check Overload Relay on top of compressor for continuity. Is there continuity?
30 An overload condition occurs at very high temperatures. Is compressor hot?
31 Replace Overload Relay. Does compressor turn ON?
32 Check U45-6 on Ctrlr PCB. Is it ON?
33 Press STOP and turn power OFF. Unplug P9 from Ctrlr PCB and turn power
back ON. Go to DIAG Screen 3, Serv-2 #2. Turn (Ovride) ON, press on/off
to energize compressor. Did U45-6 come ON?
34 Reconnect P9 to Crtir PCB, and unplug P2 from PDB. Is U45-6 still ON?
35 Press STOP and turn power OFF. Temporarily replace rbn cbl from Ctrlr PCB
(P9) to PDB (P2) and reconnect DMM clamp-on device on a compressor wire.
Turn power ON and Press START. After 15 seconds, is current >5A?
Go To
Conclusion Step
END
yes 25
no 32
yes
no
yes
no
yes
no
yes
no
yes
no
yes
no
yes
no
yes
no
yes
no
29
26
END
28
12
END
27
30
28
31
END
27
35
33
34
21
19
23
23
36
Figure 44. Rotor Ouertemperature (continued)
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Step Required Action & Evaluation
Go To
Conclusion Step
36 Press STOP and turn power OFF. Reconnect original rbn cbl and check continuity
across the compressor signal path on Relay PCB. Continuity check OK? yes 37
no 19
37 Replace Compressor Relay inside PDB.
38 Check COOL LED in PDB. Is it ON?
39 Check U45-4 on Ctrlr PCB. Is it ON?
END
yes 39
no 42
yes 40
no