Motorola GP series Service Manual

Troubleshooting Flow Chart for VCO 3-7
7.0 Troubleshooting Flow Chart for VCO
Tx
Carrier?
L253
Open
Circuit?
VCTRL
0V or
13V?
START
No LO?
VCO OK
Check
R260
TRB =
5V? @U241
Pin 19
U241
Pin 10
>1V?
Change
L253
Change
U241
AUX 3
High?
Check U201
Pin 2 for 3.2V
U241
Pin 19 =0V
AUX 4
High?
Change
U201
L243
Open
Circuit?
Change
L243
Change
U241
Change
Q261
Check for faulty
parts or dry joints of
L271, L273, C370,
C386, R339 & L320
A
A
No
No
Yes
Yes
Yes
No
No
Yes
Yes
Yes
No
Yes
No
No
Yes
Yes
No
No
Check R245
for dry joint
or faulty
No
Yes

Motorola GP series Specifications

General

Operating Temperature	-30°C to +60°C
Frequency Range	136-174 MHz
Number of Channels	16
Channel Spacing	12.5 kHz / 25 kHz
Battery Life	8 hours (with standard battery)
Operating Voltage	7.5V DC
Ingress Protection	IP54
MIL-STD	810 C, D, E, F