Motorola ASTRO XTS 5000 Detailed Service Manual page 118

Troubleshooting Charts: VCO TX/RX Unlock
VOCON TX Audio (for kit NNTN5567)—Page 2
1
Check Mic_Bias
Line on U501 for
DC Voltage
Voltage = 5.0
V?
Yes
Check signal on
U408 pin 1 while
still applying
audio signal to
radio
Yes
Data present?
Yes
Check signal on
R405
2
6881094C31-E
No
Replace U501
No
Replace U501
2
No
Clock
present?
Yes
Check signal on
R406
Synchronous
pulses
No
present?
Yes
Replace U401
5-27
Replace U501
Replace U501
November 16, 2006