Troubleshooting Flow Chart For Synthesizer - Motorola CM160 Service Information

Troubleshooting Flow Chart for Synthesizer

3.0 Troubleshooting Flow Chart for Synthesizer
Check D200, D201,
C2026, C2025, &
C2027
YES
NO
5V
U200 Pin 47
at pin 6 of
at = 14.6VDC
D200
NO
Check
R228
Is
U201 Pin 19
<40 mVDC in RX &
>4.5 VDC in TX?
(at VCO section)
?
YES
Is
RF level at
U200 Pin 32
-12 < x <-25
dBm
?
YES
Replace U200
NO
Correct
Problem
Is
?
YES
Check R201
NO
Is
U200
YES
Pin 2 >4.5 VDC in
Tx & <40 mVDC
in Rx
?
NO
Replace U200
If C2052, R208,C2067,
NO
C2068, L210 are OK, then
see VCO
troubleshooting chart
Start
Visual
check of the
Board
OK?
YES
+5V
at U200
NO
YES
Pin's
13 & 30
?
Check 5V
R e g u l a t o r
U503
Are
signals
NO
at Pin's 14 &15
of U200
?
YES
Is
there a short
NO
between Pin 47 and
Pins 14 & 15 of
U200
?
YES
Remove
Shorts
3.3V
NO
Check 3V
at U200
Regulator
pins 5, 20, 34
U503
& 36
YES
Is
Is
16.8MHz
16.8MHz NO
signal at
Signal at U200
U200 Pin
Pin 19
23?
?
YES
NO
Check
Y201 and associated
Parts
Are
Waveforms
NO
at Pins 14 & 15
triangular
?
YES
Pins 7,8 & 9
NO
of U200 toggle
when channel is
changed?
Check programming
lines between
U403 and U200
Pins 7,8 & 9
NO information
from
correct
Check uP U403
Troubleshooting
Chart
Replace U200
3-7
Replace
U200
YES
Do
YES
Is
u
P U403
?
YES