Motorola MTX series - (800;900 Mhz Frequency Generation Unit - FGU)

41
TROUBLESHOOTING FLOW CHART #4B
(800/900MHz Frequency Generation Unit - FGU)
FGU No Lo Injection/TX
Unlock
A
NO
YES
VDC at
V Con Pin 1
U205
<0.7V
?
Replace
U204
5V at
U204 Pin 11,
20, 23,
25, 42?
NO
CHECK
ONE
O.K. AS IS
O.K. AS MARKED
( )
( )
ISS.
REVISION
RLSE.
CORRECTED
AS
MARKED
ILLUSTRATOR DATEENGINEERDATE PROGRAM DISK
RLSE.
LETTERING SIZE:
REQUIRES:
EDITOR DATECHECKERDATE
Illustrator
O
SW
3/12/93
C68
VDC at
U202 Pin 1,
2 & 8 OK
?
Check Continuity
Between
U204-2 & J704-6
U204-3 & J704-15
U204-4 & J704-17
If no Fault Found
Replace U204
VDC at
U204 Pin 21,
28, 38
OK
?
Refer to
Chart #3B
Replace
U203
Check Continuity
Between
U203-24 & J704-5
U203-22 & J704-15
U203-24 & J704-8
13V
at U204
Pin 36?
16.8MHz
at U204
Pin 14?
VDC at
U203-9,
13, 14, 23
16.8MHz
at U203
Pin 10?
No 2.1MHz
2.1MHz
at U204
Pin 10?
2.5V
at U204
Pin 14?
Check
R222/C284
VDC at
CR204
Pin 6
OK?
Go to VCO
TX/RX Unlock
Routine
Chart #5B
2.5V
at U204
Pin 8 & 9
?
Check
C256, C257,
C258 & CR204
Replace
U204
NO
YES
YES
YES
NO
YES
NO
NO
YES
YES
NO NONONO
NO
NO
YES
YES
YES
YES
YES
JWB
3/22/93
JWB
3/31/93
SW
3/31/93