Troubleshooting Flow Chart For Synthesizer - Motorola Radius CM200 Service Manual

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
Check 5V
Regulator
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?
U503
Yes
Check R201
No
Is there a short
between Pin 47 and
Pins 14 & 15 of
U200?
Remove
Shorts
see VCO
3V at
No
Check 3V
U200 pins 5,
Regulator
20, 34 & 36
U508
Yes
Is
Is 16.8MHz No 16.8MHz
Signal at signal at
U200 Pin 19? U200 pin
23?
Yes
Check
Y201 and associated
parts
No
Are signals
at Pins 14 &
15 of U200?
Yes
Are Waveforms
at Pins 14 & 15
Yes
triangular?
No
No
Check programming
lines between U403
and U200 Pins 7,8 & 9
Yes
No
Check µP U403
Troubleshooting
Chart
3-7
Yes
Replace
U200
No
Do Pins
7,8 & 9 of
U200 toggle
when channel is
changed?
Yes
Is information
from µP U403
correct?
Yes
Replace U200