Motorola ASTRO XTS 3000 - Chart 29. VHF;UHF Frequency Generation Unit (FGU); Chart 30. 800 MHz Frequency Generation Unit (FGU)

10-30
Chart 29. VHF/UHF Frequency Generation Unit (FGU)
FGU No Lo Injection/TX
Unlock
Check continuity
between:
U204-2 & J1-17,
U204-3 & J1-10,
U204-4 & J1-9.
If no fault found
replace U204.
YES
MAEPF-26042-O
NO
VDC at
VCTRL (TP5),
<0.7V?
Replace
U204
5V at
U204
Pin 11, 20, 23
25, 42?
VDC at
U204 Pin 21,
28(Tx), 29(Rx)
38 & 39
OK?
13V at
U204
Pin 36?
2.1 MHz
at U204
Pin 10?
VDC at
CR205 Pin 4
OK?
2.5V at
U204
Pin 6 & 7?
Go to VCO TX/RX
Unlock
Troubleshooting
Chart C.31.
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
39
39
38
38
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
NO
YES
YES
YES
NO
YES
YES
NO
YES
YES
NO
YES
NO
OK
YES
NO
NO
Chart 30. 800 MHz Frequency Generation Unit (FGU)
FGU No Lo Injection/TX
Unlock
A
NO
MAEPF-26043-O
YES
VDC at
V Con Pin 1
U307
<0.7V?
Replace
U302
5V at
U302 Pin 11,
20, 23,
25, 42?
NO
VDC at
U305 Pin 1,
2 & 8 OK?
Check Continuity
Between
U302-2 & J1-17
U302-3 & J1-10
U302-4 & J1-9
If no fault found,
replace U302.
VDC at
U302 Pin 21,
28, 38
OK?
Refer to DC
Switch
Chart C.33
Check Continuity
Between
U304-24 & J1-8
U304-22 & J1-10
U304-25 & J1-17
13V
at U302
Pin 36?
16.8MHz
at U302
Pin 14?
VDC at
U308-9,
13, 14, 23
16.8MHz
at U304
Pin 10?
No 2.1MHz
2.1MHz
at U302
Pin 10?
2.5V
at U302
Pin 14?
Check
R306/C309
VDC at
CR301
Pin 6
OK?
Go to VCO
TX/RX Unlock
Routine
Chart C.32
2.5V
at U302
Pin 8 & 9?
Check
C301, C302,
C350 & CR301
NO
YES
YES
YES
NO
YES
NO
NO
YES
YES
NO NO
NO
NO
NO
NO
NO
YES
YES
YES
YES
YES
Replace
U304
Replace
U302