Troubleshooting Flow Chart For Synthesizer - Motorola CM140 Service Information

Commercial series cm vhf1 (136-162mhz) low power
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Troubleshooting Flow Chart for Synthesizer

3.0
Troubleshooting Flow Chart for Synthesizer
No
5V
Yes
at pin 6 of
D200
= 13VDC?
No
Check
R228
Is U201 Pin 19
<40 mVDC in RX &
>4.5 VDC in TX?
(at VCO section)
Yes
Check D200, D201,
C2026, C2025,
C2024 & C2027
Is RF level at
U200 Pin 32
-12 < x <-25
Correct
Problem
Is U200
Pin 47
Yes
No
Is U200 pin 2
>4.5 VDC in Tx &
<40 mVDC in Rx
No
Replace U200
If C2052, R208, C2067
No
C2068. C210, are OK, then
troubleshooting chart
dBm?
Yes
Replace
U200
Start
Visual
No
check of the
Board OK?
Yes
Yes
+5V at
No
U200 Pins
13 & 30?
Check 5V
Regulator
U503
Yes
Check R201
No
Is there a short
between Pin 47 and
Pins 14 & 15 of
see VCO
5V at
No
U200 pins 5,
20, 34 & 36
Yes
Is 16.8MHz
No
Signal at
U200 Pin 19?
Yes
Y201 and associated
No
Are signals
at Pins 14 &
15 of U200?
Yes
Are Waveforms
at Pins 14 & 15
triangular?
Yes
Check programming
U200?
lines between U403
and U200 Pins 7,8 & 9
Yes
Remove
Shorts
Check µP U403
Troubleshooting
Chart
3-7
Check 5V
Regulator
U503
Is
Yes
16.8MHz
Replace
signal at
U200
U200 pin
23?
No
Check
parts
No
Do Pins
7,8 & 9 of
No
U200 toggle
when channel is
changed?
Yes
No
Is information
from µP U403
correct?
Yes
Replace U200

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