No Transmit Deviation Troubleshooting Chart - Motorola XTS 2500 Service Manual

UHF1 Troubleshooting Charts: No Transmit Deviation Troubleshooting Chart

6.2.22No Transmit Deviation Troubleshooting Chart

No RF TX
Deviation
Set the radio to test mode CSQ.
Connect the radio to R4005B test box
or equivalent and inject a 1 kHz tone
mic signal with an amplitude sufficient
to provide a 3 kHz deviation out.
PTT radio using
external PTT
switch
Check waveform on test point
TP36
Do
you see a
waveform like
TX Audio 1 kHz
Tone, trace
1?
Yes
Check R213, C231.
If components are
good, replace U202.
6816985H01-F
NOTE: This chart assumes you have gone through
the VOCON TX Audio Problem Section.
Remove
No
SH201
Check waveform on U811,
pin 1. It should
look like TX Audio 1 kHz
Tone, trace 2, Vdc~1.5V.
Do
you see a
No
waveform like
TX Audio 1 kHz
Tone, trace
2?
Yes
Make sure there is 3V
on pin 4 of FL200. If not
go to DC supply failure.
Check clock on pin 8
of FL200. The waveform
should look like TX
Audio 1 kHz Tone, trace 3.
Do
you see a
waveform like No
TX Audio 1 kHz
Tone, trace
3?
Yes
Check pin 7 of FL200.
When you PTT, is should
go HIGH (3V). If it does
not go high, check the
Patriot (U800).
6.2-21
Check Vdc on U811,
If no voltage,
replace U811.
Make sure DC on U202
is there. Make sure Y200,
pin 2 has 16.8 MHz
ref output.
Check pin 1 of FL200.
It should go up to 1.5V
when you PTT. If it doesn't
check C229. If C229
is good, replace FL200.
MAEPF-27343-O
February 14, 2012