Motorola APX 3000 Detailed Service Manual page 104

5-14
Power-Up Failure – Low V_EXT_1.85 Voltage
Low V_ENT_1.85 Voltage
Measure Radio
Current
Is standy
Yes
current > 15mA
above avg?
No
Measure
V_SW_3.6
Voltage at R6510
Voltage =
V_SW_3.6
Yes
Measure Voltage
R6431 on V_5.0A
Side
Yes
4.8 < V < 5.2
No
Proceed to Low
LD08 V_5.0A
Voltage Flow
Chart
Board has a short,
replace board
Proceed to
No
Incorrect
V_SW_3.6
Voltage
Measure Voltage
at R6420
Measure Voltage
2.2 < V < 2.7?
at R6431 on
BGAP_COMP
side
Inspect U6508 and
All Supporting
Circuitry
Troubleshooting Charts: Power-Up Failure
2.2 < V < 2.7?
No
No
Replace Main
Board
Yes
Are Parts Solder
Connections &
Placement Correct
Replace Main Board
Inspect and repair
Yes
U6409 and
Supporting
Circuitry
No
Replace or repair
Parts