Motorola APX 6000 Service Manual

Troubleshooting Charts: FGU Power Failure 5-47
5.20 FGU Power Failure
VCO TX/RX
Low Power
2.5Vdc on
U710 logic pin?
No
Remove
VCO shield.
Yes
No
Yes
7/800 TX / VHF RXY707
700 RX/TX 800 RX/TXY706
VHF TX / UHF1 RX/ UHF2 RX
UHF1 TX/ UHF2 TX
Y704
Y705
VCORef Des
7
6
3
VHF TX / UHF1 RX/ UHF2 RX
700 RX/TX / 800 RX/TX / UHF1 TX/ UHF2 TX
VHF RX / 7800 TX
Freq BandU709 Pin
Note 2:
Note 3:
See Note 3
Remove
TRIDENT shield.
TX?
Check power
at input of U710
(pin 1).
Is power
> -20dBm?
No
Yes Yes
Check parts
around U710. If
OK, replace U710.
See Note 1
Check parts
around U703. If
OK, replace U703.
1.5Vdc at
L806?
No
7
6
3
Pin
700 / 800 TX / 7/800 TX / UHF1 TX/ UHF2 TX
VHF TX
Freq BandPin
Note 1:
U710
Yes
Check 1.5Vdc
supply.
No
< 0.5Vdc at
Pin 3 of
Q712?
No
Yes
Check parts
around Q712. If
OK, replace Q712.
Is power
at C810
> -20dBm?
Yes
Check parts
around Q713. If
OK, replace Q713.
No
2.5Vdc on
U709 logic pin?
Yes
Is power
output of VCO
> -20dBm?
Yes
No
No
Check parts
around VCO. If
OK, replace VCO.
Check parts
around U703. If
OK, replace U703.
See Note 2
1.5Vdc at
L821?
Check 1.5Vdc
supply.
< 0.5Vdc at
Pin 3 of
Q703?
Yes
No
< 1.5Vdc on
Pin 2 of
Q714?
< 0.5Vdc on
Pin 6 of
Q714?
No
Check parts
around Q703. If
OK, replace Q703.
Check parts
around Q714. If
OK, replace Q714.
Check logic
in PA section.
Yes
No
Yes
Is power
at C830
> -20dBm?
No
Check parts
around Q842. If
OK, replace Q842.
2.5Vdc on
U710 logic pin?
No
Yes
Check parts
around U703. If
OK, replace U703.
Yes
See Note 1
See Note 3
VHF TX?
No
Yes
Is power
at C830
> -20dBm?
Yes
Is power
at C830
> -20dBm?
No
Yes
Check parts
around Q842. If
OK, replace Q842.
No
Is power
at C799
> -20dBm?
Check parts
around U702. If
OK, replace U702.
Yes
No
Check parts
around U709. If
OK, replace U709.
700 / 800 / VHF RX / UHF1 RX/ UHF2 RX

Motorola APX 6000 Specifications

General

Brand	Motorola
Model	APX 6000
Category	Two-Way Radio
Language	English