Motorola CDM Series Detailed Service Manual page 350

Section 7: 3-4
3.0 Troubleshooting Flow Chart for Synthesizer
Check CR1202,
Correct
C1209-11,
Problem
C1229, & C1230
YES
5V
NO
Is U1201 Pin 47
at pin 6 of
at = 13VDC
CR1202
NO
YES
Check
R1218
Is U1377, Pin 2
<.1VDC in RX &
>4.5 VDC in TX?
(at VCO section)
YES
Is RF level at
U1201, Pin 32
-5 < x < 0
dBm?
YES
Are R1205,
R1206, R1208,
C1212, C1213 &
C1214 OK?
YES
Replace
U1201
6881091C63-F
NO
check of the
Board OK?
Check
U1377,
Check 9.3V
U1378 &
R e g u l a t o r
R1376
U0641
NO
YES
Is U1201 pin
2>4.5 VDC in
Tx & <.1 VDC
in Rx
NO
NO
Replace
U1201
If Q1202 Feedback Amp
NO
stage is OK, Then see
VCO troubleshooting
chart
Replace or
NO
resolder
necessary
components
Troubleshooting Flow Chart for Synthesizer
5V at
U1201 pins
Start
5, 13, 20, 34
& 36
Visual
YES
Is 16.8MHz
Signal at
U1201 Pin
YES
+9.3V at
NO
U1201
Pin 30?
Are Waveforms
at Pins 14 & 15
square?
NO
YES
Is there a short
between Pin 47
and
and U1201 Pins 7,8 & 9
Pins 14 & 15 of
U1201?
YES
Remove
Shorts
Check uP U0101
Troubleshooting
Check 5V
NO
Regulator U1250,
L1201 & R1201
YES
Is
16.8MHz
NO
signal at
YES
U1201 pin
19? 23?
YES
NO
Check Y1201,
C1204,
C1206,C1207,
CR1201. & R1203
Are signals
NO
at Pin's 14 &
15 of
U1201?
YES
Do Pins 7,
8 & 9
NO
of U1201 toggle
when channel
is
changed?
Check programming
lines between U0101
YES
Is information
NO
from uP
U0101
correct?
YES
Chart
Replace
U1201
Replace
U1201