PART TW<By DON BAISDEN.. o in this installment we lead through pitfalls of assembly an,soldering of the kit of the NI.A.No 2-3-4 Digital system. For those who like the expel

imental advantages of assembling an electronic device we know this wig go .together well

~ Last month we introduced you .to theM.A.N. 2-3-4 system and guided youthrough the construction o£ the trans-mitter "semi-kit." This month for themore intrepid, we will do the kit versionof .the transmitter and the dual charger.Actually, all we must do is to bring thetransmitter kit to "seml-kit" st.age andrefer you to last month’s article.

Before we plug the soldering iron in-to the wall and start broiling compo-nents, permit us to indulge in some pre-liminary comments of a "how-to-do"nature, and a bit of our "philosbphy."

You may notice a difference betweenthis series and comparable ones in othermagazines. First, our articles are "tight","concise", we would like to think("skimpy", our competitors might say).We do not engage in offering options,i.e., four stick possibilities, three con-figurations, elaborate sheet metal courses

and "electronics" that few withou.t anE.E. degree can comprehend. We donot believe that a couple of hundreddollars should buy our readers a "tink-erer’s delight." It should purchase a re-liable efficient system comparable to thebest commercial units . . . and that’sjust what we’ve done. This series is adistillation ... there is no more herethan you need to build the system . . .and no less. Our problem, unlike others,is not "how to fill space."

If you’re an "electronics" type, enjoyour circuit descriptions, and analyze theschematics. If you’re a model airplanebuilder .and flyer without interest orability in electronics, make believeyou’re baking a cake, simply follow therecipe and enjoy the results . . . if yourequire a lot of "icing" perhaps youshould try a different pastry chef. Twotransmitters were built from this, and

the preceding article before we set typ,--both worked beautifully and immediately.., and both were built by a typ!that still refers to .the components a~"colored beads."

You scratch builders are not g~ing tclove Us we fear. All we are going to giv~you are essentials, i.e., circuit b0ards:schematics, and a general pai’ts lisi(withoutmanufacturers’ names andnumbers). You rugged types and otherscan lay out your own boxes, etc., andtruly earn the medals you bestow onyourselves. We will repeat . . . our re-search indicates that you can’t saveenough to really make scratch buildingworthwhile, your chances of success arediminished, and, frankly, when yourlatest and most beloved creation splat-ters all over the landscape we don’twant the name of "M.A.N." to be takenin vain.

42

Soldering is an art that is the key tosuccessful electronics work. The vastmajority of all eleeronic kit ,malfunc-tions are directly attributable to badsoldering. The foliowing rules will, iffollowed, result in excellent solder con-nections. Lncidentally, the transmitterboard is, because of .the relatively largesize, an excellent training ground forthe small receiver, decoder and servoboards yet to come.

1. Spring for a new. roll of solder.Make sure it is "radio" solder, with aresin and not. an acid core. Recom-mended are Ersin Multicore 60/40 andKester’s "44" resin core solder whichis also a 60/40 alloy.

2. Obtain a soldering iron of 25-35watts. The more powerful "guns" in thehands of the inexperienced will "cook"the colored bea~ls. Unger’s pencil ironsare fine the cheapest will do admir-ably.

3. Keep a damp rag handy and wipethe tip of your iron quite often.

4. Solder your leads to the board byplacing your iron tip against the leadand the land from which the leademerges. Immediately .apply solder--which will flow instantly--and immedi-ately remove the iron ’by sliding it upthe lead and away from the board.

5. Solder rapidly, heat is your ene-my!

6. Twist and "tin" all stranded wireends before soldering to componentsand/or batteries.

7. All ~older joints and connectionsmust be shiny and smooth. Greyish,granular joints are "cold" and must bereheated till smooth and shiny sincecold solder joints create great resistance.

TRANSMITTER KIT:First thing to do is check all compo-

nents against the parts list. In all likeli-hood they will all be .there. If not, it isbetter to have replacements on orderas rapidly as possible, so as not to delaythat ~wesome momeiat known as the"smoke test."

It ~s relatively unimportant whnt"system" is used in mounting the com-ponents on the circuit board. Some pre-fer to work "across the board", i.e.,from left to right or from top to bot-tom, others prefer to go down the com-ponent list, crossing off each componentas it is soldered. But it is importantthat some system be used.

Whatever system you prefer, or de-vise, install the following componentsfirst . . . that’s right, now! Plug youriron in, once you take the plunge thewater is me:

1. Install crystal in holes 20 and 30and solder in place.

2. Find your .82uh choke (widesilver-gold-grey-red-silver bands) andwrap four turns of #24 enamel wire(supplied) around it. (See Figure.)Scrape enough of ,the enamel off the"tails" of the (Continued on page 46)

¯ MODEL AIR t SeI 1968

In this photo we see the completed assembly of the M.A.N. 2-3-4 Digitalkit. Inter-wlring between printed circuit board and stick pots i~ shown very

coil you have just wound so that theportions that are to protrude throughthe board are bare and clean, and canthus be soldered. The scraping shouldbe done gently with a razor. Bend theleads of .the .82uh choke so that theyfit, into holes 102 and 103. Insert thescraped enamel wire leads through theminuml~ered holes that will lie underthe choke when it is in place. Insert thechoke leads into holes 102 and 103 andsolder all four of the leads (not that’sa real pretty bead).

3. Install and solder the 100mf elec-

trolytic capacitor in holes 155 and 156,making sure the -t- lead in hole 156.

4. Install and solder the jumper wirefrom hole 141 to hole 142. You mayuse a lead clipped off the 100mr capaci-tor for this.

5. Install and solder diode DHD 806in lioles 84 and 85 making sure that the"marked" end is at hole 84. Polaritymust be observed in the installation ofall diodes.

These specific instructions were giv-en to place a few components on theboard so as to give you orientation in

clearly, plus the wiring of the separate dual charger and the battery pack.Main advantage of the system is room plus accessibility of all components.

the placement of parts and because we ...wanted to make sure that you scrapedyour enamel, observed polarity on yourdiodes and electrolytic, and did notoverlook your jumper which is easy tooverlook since it is not a "pretty bead."

The rest is a "piece of cake" albeitwithout "icing" so decide on your sys-tem and start soldering. Just follow thecomponent diagram .and the componentplacement list and you cannot miss--provided that you do not work whenyou are )~atigued.

After all your components are

~’i!:}nounted, check the board carefully,~especially to see if all the right colorst!i:’;are on the rig,ht resistors. Now go back

to last month s article and finish yournow "semi-kit", which, incidentally isa bit easier than the standard "semi-kit"because the letters and numbers indicat-ing "pot" wire locations have not beenerased by "dip soldering."

DUAL CHARGER/TRANSMIT-TER POWER PACK

The construction of the charger isapparent from the accompanying dia,gram and no difficulty should be experi-enced if you observe the following tips:¯ 1. Polarity must be observed in the

placement of the diodes Fl--the markedends should be soldered into holes 4and 12.

2. Hole 6 and 19 are for self tappingscrews--you are not missing compo-nents!

3. In soldering to the #49 bulbbases and contacts :the solder areasshould be "tinned," i..e., solder flo~vedon before solder leads in ¯place. Dis-carded leads should be used as the"straps" from the bulb bases to holes7 and 8.

The two plastic battery boxes sup-plied are ultimately mounted alongsideeach other forming .a long box with ten"cel! compar.tments" side by side. Since0nly eight cells are to be used we willnot use the extreme left end cell com-partment in the left hand box or theextreme right, cell compartment in theright hand box for cells. With an awl,

. punch a hole in the top of each batterybox over the u.nused compartment. Simi-larly, punch holes in the ends "of theboxes where they meet each other. Thefirs~ holes are for your negative andpositive "leads." The last two are soyou can continue your Wiring of cellsin series, i.e., the fourth cell in the first

¯ box to the first or left-most cell in thesecond, or right-hand, box. Wire yourfirst foui cells in series side by sideleaving, a little slack (for strain relief)between cells. Solder .a long lead to thefree terminal of the first cell in theseries. (if it is negative use black wire,if positive, use red). Solder a three inchwire to the free terminal of the last cellof the first four~ and run the l[ree endthrough the hole punched in the end of-the first box and into the second boxthrough the hole punched in the end ofthe second box. Cut this wire to lengthleaving a little slack and continue towire the remaining cells in series. Whenyou’ve finished make sure one of yourend leads is atthched to a negative ter-minal (black wire) and the other to apositive terminal (red wire). If not, findyour "goof" and rewire. Refer to lastmonth’s article for the installation andoperation of th~ dual charger and trans-mitter power pack.

Next month the fun will start withthe decoder, (Continued on next page)

WAVEFORM @ ’A’ WAVEFORM @ qJ" ’C’ and ’D"

SPECIAL .82 uh CHOKE

Four turns no. 24 coatedcopper wire around cap-icitor-see text.

Scrape (remove) allcoating from endsof wire leads.

MODEL AIRPLANE NEWS ¯ September, 1968 47

DIGITAL SYSTEMCONTINUED

semi-kit and kit. You will then appreci-ate the magnificent miniaturization ofthis system . . . and wait ’till you seethe M.A.N. 2-3-4 mini-servos. One ofour contributors is planning on puttingthe system in a Minnie Mambo--withailerons yet!

M.A.N. 234 TRANSMITTER PARTS4 3 2

CHAN. CHAN. CHAN.RESISTORS

100 ohm 1 1 11K 1 1 14.7K 2 2 210K 6 6 633K 1 1 147K 5 4 356K 4 3 2100K 2 2 2

POTS5K AB Type 4 3 250K Trimmer 4 3 2

MYLAR ORSM CAPS.

56pf 1 1 1.0047 MF 5 4 3.047 4 3 2.15 1 1 1.22 2 2 2

TUBULARELECTROLYTIC

100 M.F. 1 1 1DISC.CAPACITORS

100 p,f 1 1 1.001 MF 6 5 4 ’.02 5 5 5

TRANSISTORS2N 3643 2 2 22N 2924 9 8 7

DIODES"::~ DHD 806 5 4 3~0LDED CHOKES

.82 uh 1 1 11.5 uh 1 1 112 uh 2 2 2

HARDWARE(SAME FOR 2, 3 & 4)

O.S. STICK ASSEMBLY

BASE PLATE

YOKE B~

SELF TAPPING~__~SCREW

BusHING NUT

YOKE

ALLEN, WRENCH- 1Vz ram.

SIDE PLATE

J POTENTIOMETER

#2 x ~" SELF TAPPING SCRL~

POT CARRIER

4/40 x ¼" PAN HEAD SCREW

THREADED BUSHING

SWITCH. GUARD 1BRASS STANDOFF 1NYLON STANDOFF 1DPDT SLIDE SWITCH 1BATTERY SNAP & CABLE 1HANDLE ASSEMBLY 1ANTENNA FEED THRU 1CENTER LOADED ANTENNA1STICK-ON RUBBER FEET 4FIELD ST.RENGTH

METER KIT 1(Meter .02 Gap, IN 34 Diode

& 12uh Choke)1/4" GROMMET (Rubber) 1#4 x 1/4 SHEET METAL

SCREWS 64-40 x 1/4 SCREWS 24-40 x 5/ld SCREWS 3

4-40 x 1/4 SELi~-TAP SCREWS64-40 LOCKING NUT 1CHARGING SOCKET

ASSEMBLY 11.5 MM. A~ LLEN WRENCH 1O.S. STICK ASSEMBLY KIT

(1 ea. for 2 & 3 Chan.)(2 for 4 Chan. )

5--M.A.N. 2-3-4 DIGITAL SYSTEMSPECIAL HARDWARE

TX CASE 1PC BOARD 1TRANSMITTER CRYSTAL 1

SPECIAL HARDWARE2 CHANNEL

PLASTIC cOVER PLATE &

2 #4 x V4 SHEET METALSCREWS

3 CHANNELPOT BRACKET, PLASTIC

MOTOR CONTROL LEVER& (2) #4 x 1/4 SHEETMETAL SCREWS

WIRE & SLEEVING PACKAGE(4) 10" white(4) 10" orange(1) 10" yello,w ’(1) 10" violet(1) 10" blue(1) 10" green.(1) 2" shrink tubing(1) 2" # 16 Buss wire(1) 4" #24 Wire (Link)

11

BLACK BATi’ER¥ WIREVIEW OF COppER OR LAND SOLDERS TO LANDSIDE OF BOARD SHOWINGROUTING OF BATITcRY ANDFOTENTtOMETER WIRES.

TO LAND

TO AILERONPOTENTIOMETES,"

FOTENTIOMETER.RUDDER

POTENTIOMETER..ORANGE

VIOLET

0TE 1: ALL (4) ORANGE POTENTIOMETER NOTE ~ OTHER’ POrENTIOMETER WIRES(IRES SOLDER TO LAND ~47.133.51.137 SOLDER TO LANDS PRINTED WITH LETTERS40LE NUMBERS). ’ AND NUMBERS AS SHOWN IN SKETCH.

BLUEORANGE

:WHITE

TRANSMITTER R.F. SECTION CIRCUIT

I-ISIGNAL INPUT

Q9 -- 2N2924QIO, Q11---2N3643

CENTER LOADEDANTENNA

TRANSMITTER POWER PACK AND DUAL CHARGER CIRCUIT

AC LINE CORD

’ECEIVER BATTERYHARGING CORD.

ISOLATION TRANSFORMER

F1

TRANSMITTERCHARGING PLUG.

49 BULB

F1

49 BULB

TRANSMITTERPOWER SWITCH

9.6 VoltRECHARGEABLE PACK.

R.F. DEMODULATOR

MODULATED R.F. CARRIER

DEMODULATED SIGNAL

)DEL AIRPLANE NBNS ¯ SeptFmber, 1968 49