Motorola Pro3100 Detailed Service Manual

Section 9: 3-4 Troubleshooting Flow Chart for Synthesizer
6881091C63-F
3.0 Troubleshooting Flow Chart for Synthesizer
5V
at pin 6 of
D4201
Is information
from μP U0101
correct?
Is U4201 Pin 47
at = 13VDC
Is U4301 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
U4211
+5V at
U4201
Pin’s
13 & 30?
Is 16.8MHz
Signal at
U4201 Pin
19?
Check Y4261,
C4261, C4262,
C4263, D4261 &
R4261
Are signals
at Pin’s 14 &
15 of U4201?
Check
R4201
Check C4381
Is U4201 pin 2
>4.5 VDC in Rx &
<40 mVDC in Rx
Replace
U4201
Remove
Shorts
Is there a short
between Pin 47 and
Pins 14 & 15 of
U4201?
Replace or
resolder
necessary
components
Is RF level at
U4201 Pin 32
-12 < x <-25
dBm?
Are R4221,R4222,
R4223,C4221,C422
2,
& C4223 OK?
Replace
U4201
If L4225, C4229 & C4227
are OK, then see VCO
troubleshooting chart
Are Waveforms
at Pins 14 & 15
triangular?
Do Pins 7,8 & 9
of U4201 toggle
when channel is
changed?
Check programming
lines between U0101
and U4201 Pins 7,8 & 9
Replace
U4201
Check uP U0101
Troubleshooting
Chart
NO
YES
NO
YES
NO
YES
NO
NO
NO
YES
YES
NO
YES
YES
NO
YES
YES
YES
NO
NO
NO
NO
YES
NO
YES
YES
Check D4201,
C4202, C4203, &
C4206
5V at U4201
pins 5, 20, 34
& 36
Ch e c k 5 V
Regulator
U4211
Is
16.8MHz
signal at
U4201 pin
23?
Replace
U4201
YES
NO
NO
YES
NO
YES

Motorola Pro3100 Specifications

General

Brand	Motorola
Model	Pro3100
Category	Two-Way Radio
Language	English