Troubleshooting Flow Chart For Synthesizer - Motorola HT Series Service Manual

8-46

8.14.5 Troubleshooting Flow Chart for Synthesizer

Check D201, D202,
Correct
C244, C245, C246 &
Problem
C247.
YES
5V
NO
Is U201 Pin 47
at pin 6 of
AT = 13 VDC
D201
NO
YES
Check
L200
Is U201 Pin 28
at 4.6 VDC?
YES
Is RF level at
U201 Pin 32
as indicated?
YES
Are C226, R209,
R210, L204, C231,
C220, C225, C218,
R216, and R217
OK?
YES
Replace U201
NO
NO
Replace U201
If L203, C227 & C228
NO
are OK, then see VCO
troubleshooting chart
Replace or
NO
resolder
defective
components
Maintenance: 800 MHz Troubleshooting Charts
Start
Visual
check of the
Board OK?
YES
YES
+5V at U201
NO
Pin's
13 & 30?
Check 5V
Regulator
Are the wave-
forms
NO
at Pin's 14
&15 of U201
rectangular?
YES
Is there a short
NO
between Pin 47 and
Pins 14 & 15 of
U201?
YES
Remove
Shorts
NO Check U248
3.3V at U201
& L202
pins 5, 20, 34
& 36
YES
Is
NO
Is 16.8MHz 16.8MHz
Signal at signal at
U201 Pin 19?
U201 pin
23?
NO
YES
Check FL201, C235,
C237, C236, CR203
& R211.
NO
Are Waveforms
at Pins 14 & 15
triangular?
YES
Do Pins
7,8 & 9 of U201
NO
toggle when
channel is
changed?
Check programming
lines between U409
and U201 Pins 7,8 & 9
NO
Is information
from
correct?
Check uP U409
Troubleshooting
Chart
Replace U201
Replace
U201
YES
YES
µ
P U409
YES