Motorola APX 6000 - Page 120

5-14 Troubleshooting Charts: Power-Up Failure
Power-Up Failure – Low V_EXT_1.85 Voltage
Low V_EXT_1.85 Voltage
Measure Radio
Current
Is Standby
Current more
than 15mA above
average?
Board has a short,
Replace VOCON
Yes
Measure
V_SW_3.6
Voltage at R6510
Voltage =
V_SW_3.6
Proceed to
Incorrect
Voltage
V_SW_3.6
Measure Voltage
R6431 on
VCC_5.0A Side
4.8 < V < 5.2?
Proceed to Low
LDO8 VCC_5.0A
Voltage Flow
Chart
Are Parts Solder
Connections and
Placement Correct
Replace or Repair
Part/s
Replace VOCON
Board
No
No
Yes
Yes
No
Measure Voltage
at R6431 on
BGAP_COMP
Side
2.2 < V < 2.7?
Measure Voltage
at R6420
2.2 < V < 2.7?
Replace VOCON
Board
Inspect and Repair
U6409 and
Supporting
Circuitry
Inspect U6508 and
All Supporting
Circuitry
No
Yes
Yes
No
No
Yes