Motorola CM360 Service Information

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

Motorola CM360 Specifications

General

Brand	Motorola
Model	CM360
Category	Radio
Language	English