Motorola APX 5000 Service Manual page 110

5-4
5.3 Power-Up Failure – VOCON Board
VOCON Board Power Up
Problem
Measure Voltage
at R6505
No
6 < V < 9?
Yes
Measure Voltage
at R6542
No
3.3 < V < 3.9
Yes
Use Oscilloscope
to Measure R6572
No
Freq = 24MHz
1.6 < V < 1.9
Yes
Measure All Probe
Spots from Above
Table
Voltages =
Level
No Yes
Proceed to
Specified Flow
Chart in Table
Name
VCC_1.875
VCC_1.55
VCC_2.775D
VCC_2.775
VCC_2.8
VCC_5.0A
VCC_3.3
Proceed to
VCC_3.0A
Incorrect B+
Voltage Flow VCC_SW_3.6
Chart
VCC_1.85
VCC_SW_1.4
Note:
1. Probe C4001 and observe 1.875 V. If absent then return board to depot for repair.
Proceed to Low
VCC_SW_3.6
Flow Chart
Repair or Replace Replace VOCON
Part/s
No
Inspect Y6501 and Are Parts Solder
All supporting Connections and
Circuitry Placement Correct
Use Oscilloscope
Replace VOCON
Impedance Probe
Board
to Measure
No
Yes
Use Oscilloscope
1.6 < V < 1.9
to Measure R6115
Measure Voltage
at R6203
Ref Description
C4001 LDO Output
R6561 LDO Output
R4011 LDO Output
R6563 LDO Output
R6564 LDO Output
R6565 LDO Output
R6566 LDO Output
R6567 LDO Output
C6561 Switching Output 3.6±10%
R6570 LDO Output
E6502 Switching Output 1.4±10%
Replace VOCON
Board
1.6 < V < 1.9
Yes
Measure Voltage
Yes
and High
Freq = 12MHz
1.3 < V < 1.9
C6602
Yes
Freq = 32kHz
1.6 < V < 1.9
Replace VOCON
Board
Troubleshooting Charts: Power-Up Failure
Level V
1.875±10% Refer to note 1
1.55±10% Low LDO3 VCC_1.55 Voltage
2.775±10% Low LDO10 VCC_3.3 Voltage
2.775±10% Low LDO10 VCC_3.3 Voltage
2.8±10% Low LDO10 VCC_3.3 Voltage
5.0±10% Low LDO8 VCC_5.0A Voltage
3.3±10% Low LDO10 VCC_3.3 Voltage
3.0±10% Low LDO10 VCC_3.3 Voltage
Low VCC_SW_3.6 Voltage
1.85±10% Low VCC_1.85 Voltage
Low VCC_SW_1.4 Voltage
No
OMAP is Out of
Yes Reset, Proceed to
Memory Flow
Chart
at R2217
No
Inspect Y6601
Circuit
Are Parts Solder
Connections and
Placement Correct
No
Yes
Repair or Replace
Part/s
Flow Chart
No