Motorola APX 2000 Detailed Service Manual

5-50 Troubleshooting Charts: VCO Failure
VCO Failure – Page 5 (VHF)
Is power at
C3240
>-20dBm?
Take continuity
check of traces to
U702.
4
Is power at U3238 input
Tx: C3160
Rx: C3159
>-20dBm?
Check parts around
U3238. If OK,
replace U3238.
Control voltage
at R705
0.3<Vdc<10.6?
Is Vdc at R3200 high at
Rx and low at Tx and
R3202 high at Tx and
low at Rx?
Is Vdc = 4.55V at pin
3 of Q3227 during
Rx and at Q3267
during Tx?
For Tx: Check and visual inspect D3246-
D3249, L3250, C3251, C3252, C3254,
C3256, C3258.
For Rx: Check and visual inspect D3206-
D3209, L3210, C3211, C3212, C3214,
L3216, C3217.
.
Is Vdc at C742 5V,
Vdc at C726, C734,
C737 2.775V?
Is Vdc at Y701
pin 4 2.775V?
16.8MHz at pin
3 of Y701 and
C736?
16.8MHz at
L753?
10.8Vdc at pin2
of D723?
2.775Vdc at pin
4 of D722?
Check and visual
inspect U746 circuitry.
Fault found?
Check 2.775V and
5V supply.
Check 2.775V
supply.
Replace Y701
and/or C736.
Replace the
suspected
components.
Replace U702.
Check D722, D723,
C716, C717, C718,
C719.
No
Yes
Yes
Yes
Yes
No
Yes
No
No
No
Yes
Yes
Yes
Yes
No
No
No
No
No
No
Yes
Yes
No
Yes

Motorola APX 2000 Specifications

General

IP Rating	IP67
Operating Temperature	-30°C to +60°C
GPS	Optional
Bluetooth	No
Frequency Range	700/800 MHz
Power Output	1-5 W (VHF), 1-3 W (700/800 MHz)
Channels	Up to 1, 000
Battery Life	Up to 10 hours (digital)
Digital Protocol	APCO P25
Frequency	VHF: 136-174 MHz, UHF: 380-470 MHz, 700/800 MHz: 764-870 MHz
Power	1-3W (700/800 MHz), 1-5W (VHF)