Midland Radio Corporation TSB-131108 90-2503 RFI.docx Page 1 of 1

Revision: Initial Release

Revision Date: November 8, 2013 Subject: RF Interference Issue: When PTT is activated the radio may reboot due to RF interference

to the 90-2503 control head. Various other anomalies have been reported also.

Corrective action: RF interference can be eliminated by removing C5 and adding:

2 ea. 1nf/0402/50V/10% 3 ea. 100pf/0402/50V/5% 1ea. 1nf/ 0603/50V/5%

See the following pages for proper modification

Technical Service Bulletin

TSB-131108 Models: 90-2503 Deluxe Control Head Used with SynTech III Mobile Radios

4700

10-03-2011

ASSY PCB LARGE LCD AND KEYPAD VR 4700

TK BDK GENIS LCD VE TUS TAKIMI AT 4700

432

SHTM 10-03-2011

A

5999-9937-2231

CEMAL KIRLILARM.ERGUN / M.CAPARMUSTAFA ERGUN

WRITTEN AUTHORITY FROM THE PROPRIETORS.

PARTIES IN ANY FORM WHATEVER IS NOT PERMITTED WITHOUT

ALL RIGHTS RESERVED, REPRODUCTION OR ISSUE TO THIRD

HER HAKKI MAHFUZDUR. YAZILI IZIN OLMADAN DOKUMANLARIN

HICBIR KISMI KOPYA, KAYIT, BASIM VEYA DIGER HERHANGI

BIR SEKILDE COGALTILAMAZ VE YAYINLANAMAZ.

HC-ST-001 EK-17D

CHECKED

KONTROL

TANIM/DESCRIPTION

YENILENEN

SUPERSEDES

PREPARED

HAZIRLAYAN

DOKUMAN NO./DOCUMENT NO.

BOLUM

DEPT.

T.SF.

T.SH.

APPROVAL

ONAY

SH.

SF.

PREPARATION DT.

HAZIRLANIS TR.

L.C.

D.K.

FORM A 3

GECERLILIK TR.

EFECTIVITY DT.REV.

REV.PROJE/PROJECT:

HABERLESME VE BILGI TEKNOLOJILERI GRUBU

COMMUNICATION AND INFORMATION TECHNOLOGIES DIVISION

OZLEM

NOT/ NOTE

COMPONENTS SHOWN WITH `T_REF.NO` SHALL NOT BE MOUNTED.

`T_KONUM NO` BICIMINDE BELIRTILEN MALZEMELER TAKILMAYACAKTIR.110-2

1

ZD31

ZD30

T_R64

TR40

TP32

TP89

TP88

TP87

TP86

TP85

TP84

TP83

TP82

TP81

TP80

TP8

TP79

TP78

TP77

TP76

TP75

TP74

TP73

TP72

TP71

TP70

TP7

TP62

TP61

TP60

TP6

TP54

TP53

TP52

TP51

TP50

TP5

TP43

TP42

TP41

TP40

TP4

TP34

TP33

TP31

TP30

TP3

TP22

TP21

TP20

TP2

TP18

TP17 TP16

TP15

TP14

TP13

TP123

TP12

TP11

TP103

TP102

TP101

TP100

TP1

TH1

R85

R87R86

R84

R83

R82

T_R39

R81

R80

R61

R60

R73

R71

R56

R55

R74

R57

R52

R51

R50

R49

R72

R70

R54

R47

R46

R45

R44

R41

R75

R63

R62

R48

R42

R35

R53

R43

R37

R33

R36

R32

R77

R76

R34

R31

R30

R65

R40

R2

R1

J5

1

J4

J3

J2

IC71

IC7

IC6

IC5

IC42

IC41

IC2

IC11

IC1

DTR2

DTR7

DTR50

DTR101

DTR1

D70

D1

1

C59

C73

C72

C71

C69

C68

C67

C66

C65

C64

C63

C62

C60

C51

C49

C57

C42

C9

C8

C54

C52

C48

C46

C36

C29

C28

C27

C26

C25

C24

C23

C22

C17C15

C7

C6

C50

C5

C43

C41

C40

C4

C37

C35

C34

C33

C32

C31

C30

C3

C21

C20

C19

C18

C16

C14

C13

C12

C11

C101 C100

C10

C74

C70

C61

C58

C56

C55

C53

C47

C45

C44

C39

C38

C2

C1

T_BD70

BD72

BD71

7000

MERGUNPencil

MERGUNRectangle

MERGUNText BoxAdd_C5

MERGUNRectangle

MERGUNRectangle

MERGUNRectangle

MERGUNRectangle

MERGUNText BoxC84

MERGUNRectangle

MERGUNText BoxC83

MERGUNRectangle

MERGUNText BoxC80

MERGUNText BoxC81

MERGUNText BoxC82

MERGUNText BoxRemove_C5