Troubleshooting Flow Chart For Synthesizer - Motorola 6864115B62-C Detailed Service Manual

3-8
4.0

Troubleshooting Flow Chart for Synthesizer

No
5V
Yes
at pin 6 of
D3201
= 13VDC ?
No
Check
R3201
Is U3301 Pin 19
<40 mVDC in RX &
>4.5 VDC in TX?
(at VCO section)
Yes
Check D3201,
C3202, C3203,
C3205 & C3206
Is RF level at
U3201 Pin 32
-12 < x <-25
R3222, R3223,
C3221, C3222,
Correct
Problem
Is U3201
Pin 47
Yes
No
Is U3201 pin 2
>4.5 VDC in Tx &
<40 mVDC in Rx
No
Replace
U3201
If R3227, C3226 & C3227
No
are OK, then see VCO
troubleshooting chart
dBm?
Yes
Are
R3221,
No
& C3224
OK?
Yes
Replace
U3201
Start
Visual
No
check of the
Board OK?
Yes
Yes
+5V at
No
U3201 Pin's
13 & 30?
Check 5V
Regulator
U3211
Yes
Check C3319
No
Is there a short
between Pin 47 and
Pins 14 & 15 of
Replace or resolder
necessary components
TROUBLESHOOTING CHARTS
5V at
No
U3201 pins 5,
20, 34 & 36
Yes
Is 16.8MHz No
Signal at
U3201 Pin
19?
Yes
Y3261, Y3263 and
associated Parts
No
Are signals
at Pin's 14 &
15 of U3201?
Yes
Are Waveforms
at Pins 14 & 15
triangular?
Yes
Check programming
U3201?
lines between U0101
and U3201 Pins 7,8 & 9
Yes
Remove
Shorts
Check µP U0101
Troubleshooting
Chart
Check 5V
Regulator
U3211, R3211
Is
Yes
16.8MHz
Replace
signal at
U3201
U3201 pin
23?
No
Check
No
Do Pins
7,8 & 9 of
No
U3201 toggle
when channel is
changed?
Yes
No
Is information
from µP U0101
correct?
Yes
Replace
U3201