Motorola 6864115B62-C

3-4 Low Band TROUBLESHOOTING CHARTS
3.0 Troubleshooting Flow Chart for Synthesizer
Is
U1201 pin 2
>4.5 VDC in Tx &
<.1 VDC in Rx
?
+9.3V
at U1201
Pin 30
?
Is
U1201 Pin 47
at = 13VDC
?
Are
signals
at Pin’s 14 &
15 of U1201
?
Is
RF level at
U1201, Pin 32
-5 < x < 0 dBm
?
5V
at pin 6 of
CR1202
Is
information
from uP U0101
correct?
Is
U1377, Pin 2
<.1VDC in RX &
>4.5 VDC in TX?
(at VCO section)
Start
Visual
check of the
Board OK
?
Correct
Problem
Check 9.3V
Regulator
U0641
Is
16.8MHz
Signal at
U1201 Pin
19?
Check Y1201,
C1204,
C1206,C1207,
CR1201. & R1203
Check
R1218
Check C3319
Replace
U1201
Remove
Shorts
Is
there a short
between Pin 47 and
Pins 14 & 15 of
U1201?
Replace or
resolder
necessary
components
Are
R1205, R1206,
R1208, C1212,
C1213 & C1214
OK?
Replace
U1201
If Q1202
Feedback Amp stage is OK,
Then see VCO
troubleshooting chart
Are
Waveforms
at Pins 14 & 15
triangular
?
Do
Pins 7,8 & 9
of U1201 toggle
when channel is
changed
?
Check programming
lines between U0101
and U1201 Pins 7,8 & 9
Replace
U1201
Check uP U0101
Troubleshooting
Chart
NO
YES
NO
YES
NO
YES
NO
NO
NO
YES
YES
NO
YES
YES
NO
YES
YES
YES
NO
NO
NO
NO
YES
NO
YES
YES
5V at
U1201 pins 5,
13, 20, 24 &
36 ?
Check 5V
Regulator U1250,
L1201 & R1201
Is
16.8MHz
signal at
U1201 Pin
23?
Replace
U1201
YES
NO
NO
YES
NO
YES
Check D3201,
C3203, C3205, &
C3206