Motorola APX 7500 Detailed Service Manual page 124

7-8
A+ present at U1300-2
1
J6_IGNITION
CH_IGNITION
Is 13.2V
Yes
present at
Q1311-2?
No
Yes
Does Q1311-1
measure 0V?
No
Is 3.3V
Yes
present at
Q1302-1?
No
No
Is R1307 placed &
measure 4.7K?
Yes
No
Is R1315 placed &
measure 10K?
Yes
2
Verify 0 Ohm jumper 1346 is
placed properly on the board.
Check/Replace Voltage
Regulator U1305.
September 9, 2011
Troubleshooting Charts and Error Codes Troubleshooting Charts
STOP
Replace MOSFET
Q1311.
Replace transistor
package Q1302.
Correctly place the
4.7K resistor
R1307.
1
Correctly place the
10K resistor
R1315.
1
UNSW_3.3V
Is 3.3V
No
present at
R1346?
Yes
STOP
VCC_5V
No
Is 5V present
at U1300-1?
Yes
VCC_5V present at U1300-1
SWB+
Is 13.2V
No
present at
Q1306-2?
Yes
SWB+ present at Q1306-2
9.6V_WL
Is 9.6V
No
present at
R2315?
Yes
4.8V_WL
No
Is 4.8V present at
test point 4.8V_WL?
Yes
2.2V_WL
Is 2.2V
No
present at
R2321?
Yes
STOP
2
Figure 7-6. Controller Board DC Voltages - B
Yes
Is 3V present Replace 5V
at U1300-7? Regulator U1300.
No
Is 3.3V
Yes
Replace transistor
present at
package Q1308.
Q1308-2?
No
Reprogram/
Replace
AVR U1311
Yes
Does Q1306-1 Replace MOSFET
measure 0V? Q1306.
No
Is 3.3V
Yes
Replace transistor
present at
package Q1305.
Q1305-5?
No
Reprogram/
Replace
AVR U1311
Verify 0 Ohm jumper R2315 is placed properly.
Verify R1320 is placed & measures 33.2K.
Verify R2317 is placed & measures 4.75K.
Check/Replace Voltage Regulator U1319.
Verify R2316 is placed & measures 33K.
Verify R1354 is placed & measures 18K.
Verify R1355 is placed & measures 15K.
Verify 0 Ohm jumper R2321 is
placed properly on the board.
68009482001