Motorola APX 7000 Detailed Service Manual page 107

Troubleshooting Charts: Power-Up Failure
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_SW_1.875 R2302_2 Switching Output 1.875±10%
VCC_SW_1.4
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_4 LDO Output
R6561_6 LDO Output
R4011_4 LDO Output
R6563_6 LDO Output
R6564_6 LDO Output
R6565_6 LDO Output
R6566_6 LDO Output
R6567_6 LDO Output
C6561_6 Switching Output 3.6±10%
E6502_6 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
Level V
1.875±10% Low LDO3 VCC_1.55 Voltage
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
Low VCC_SW_1.875 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
5-3
Flow Chart
No