Motorola ASTRO XTS 5000 Detailed Service Manual page 99

Troubleshooting Charts: VOCON RX Audio
5.13 VOCON RX Audio—Page 1
Bad SINAD
Bad 20db Quieting
No Recovered Audio
Inject Standard
Input into Antenna
Connector
Check Preamp
Input Signal at
C533
No
Signal
Present?
Yes
Check
Distortion of
Signal at C533
No
THD <3%?
Yes
1
6881094C31-D
A standard input is an
RF signal with a 1 kHz
tone modulated with 3 kHz
deviation in a 25 kHz channel.
Probe R403 for
Data, Compare
Present?
with RX SAP
waveform, Trace 2
Replace U501
(GCAP II)
flowchart
* on NTN9564, NNTN4563 & NNTN4819 VOCON boards
** on NNTN4717 VOCON board
Probe R405
for Clock Signal,
No
Data
Compare with
RX SAP
waveform, Trace 3
Yes
Go to
RX RF
5-21
No
Clock
Present?
Yes
Probe R406 for
Frame Sync Signal,
Compare with
RX SAP waveform,
Trace 1
Frame
Yes
Sync
Present?
No
Replace U301*
Replace U401**
(FLIPPER)
MAEPF-27394-A
July 21, 2004