Motorola MTX series Theory/Troubleshooting Manual

40
TROUBLESHOOTING FLOW CHART #4A
(VHF/UHF Frequency Generation Unit - FGU)
FGU No Lo Injection/TX
Unlock
Check Continuity
between J1-17 &
J104-17, J1-15 &
J104-15,
J1-5 & J104-6
if No Fault Found
Replace U204
YES
MAEPF-23272-O
NO
VDC at
VCTRL (TP5),
<0.7V?
Replace
U204
5V at
U204
Pin 20, 23,
25, 41?
VDC at
U204 Pin 21,
28(Tx), 29(Rx)
37 & 38
OK?
13V at
U204
Pin 35?
2.1 MHz
at U204
Pin 11?
VDC at
CR205 Pin 4
OK?
2.5V at
U204
Pin 7 & 8?
Go to VCO TX/RX
Unlock
Troubleshooting
Chart #5A
Check CR205,
CR206, C266, C267,
C284 & C285(V),
C282, C259
VDC at
U202 Pin 1,
2 & 8 OK?
Replace
U202
16.8 MHz
at U204
Pin 14?
2.5V at
U204
Pin 14?
Check C256,
C257, C258 &
CR204
Replace
U204
16.8 MHz
at U203
Pin 10?
Replace
U204
Check Connection
at C274, R221(V),
R222(U)
Replace
U203
IC PIN VOLTAGE
U202 1, 2
8
5V
7.5V
U204 21
28
28
29
29
38
38
37
37
1.6V
1.7V (VHF TX)
1.6V (UHF TX)
1.8V (VHF RX)
1.6V (UHF RX)
4.5V (TX)
0.7V (RX)
4.5V (HIGH END)
0V (LOW END)
CR205 4 -7.5V (HIGH END)
0V (LOW END)
No 2.1 MHz
NO
YES NO
NO
YES
YES
YES
NO
YES
YES NO
YES
YES
NO
YES
NO
OK
YES
NO
JEDI Frequency
Generation Unit Troubleshooting Chart
CHECK
ONE
O.K. AS IS O.K. AS MARKED
( )
( )
ISS.
REVISION
RLSE.
CORRECTED AS MARKED
ILLUSTRATOR DATEENGINEERDATE PROGRAM DISK
DESCRIPTION
TECHNICAL PUBLICATIONS DEPT.
RLSE.
DWG. NO.
LETTERING SIZE:
REQUIRES:
EDITOR DATECHECKERDATE
Illustrator
O
MAEPF-23272
SW
12/16/92
3/31/93
JWB
C63
SW 3/31/93
JWB 3/31/93

Motorola MTX series Specifications

General

Brand	Motorola
Model	MTX series
Category	Portable Radio
Language	English