Troubleshooting Flow Chart For Synthesizer - Motorola CDM Series Detailed Service Manual

Section 11: 3-6
3.0

Troubleshooting Flow Chart for Synthesizer

No
5V
Yes
Is U3201
at pin 6 of
Pin 47
D3201
= 13VDC?
No
Check
R3201
Is U3301 Pin 19
<40 mVDC in RX &
>4.5 VDC in TX?
(at VCO section)
Yes
Check D3201,
C3202, C3203,
C3205 & C3206
Is RF level at
U3201 Pin 32
-12 < x <-25
dBm?
Are
R3221,
R3222, R3223,
C3221, C3222,
& C3224
OK?
Replace
U3201
6881091C63-F
No
Correct
Problem
No
Yes
Check 5V
Regulator
U3211
No
Is U3201 pin 2 Yes
>4.5 VDC in Tx &
<40 mVDC in Rx
No
Replace
U3201
If R3227, C3226 & C3227
No
are OK, then see VCO
troubleshooting chart
Yes
No
Replace or resolder
necessary components
Yes
Troubleshooting Flow Chart for Synthesizer
5V at
U3201 pins 5,
Start
20, 34 & 36
Visual
check of the
Board OK?
Yes
Is 16.8MHz
Signal at
Yes
U3201 Pin
+5V at
19?
U3201 Pins
13 & 30? Yes
Are signals
at Pins 14 &
15 of U3201?
Yes
Check C3319
No
Is there a short
between Pin 47 and
Pins 14 & 15 of
U3201?
Yes
Remove
Shorts
No
Check 5V
Regulator
U3211, R3211
Yes
Is
Yes
No
16.8MHz
signal at
U3201 pin
23?
No
Check
Y3261, Y3263 and
associated parts
No
No
Are Waveforms
at Pins 14 & 15
triangular?
Yes
Do Pins
7,8 & 9 of
No
U3201 toggle
when channel is
changed?
Check programming
lines between U0101
and U3201 Pins 7,8 & 9
No
Is information
from µP U0101
correct?
Check µP U0101
Troubleshooting
Chart
Replace
U3201
Replace
U3201
Yes
Yes