Service manual

132 5
Power Supply Troubleshooting
TROUBLSHOOT THE FAN AND THE A50 DC-DC CONVERTER
2. Troubleshoot the A50 DC-DC Converter
1. Turn the analyzer power off.
2. Remove the A50 from the A20 motherboard. The cable from the A50P2 and the cable
from the A50P3 are connected.
3. Turn the analyzer power on.
• If the A50 SHUTDOWN LED is still off, replace the A50 DC-DC Converter.
• If one or more LEDs are still off, replace the A50 DC-DC Converter.
• If the A50 SHUTDOWN LED goes on and Five LEDs go on, continue with
Measure the A50 Power Supplies.
Measure the A50 Power Supplies
Measure the power supply voltages on A50 using a voltmeter with a small probe. See Table
5-1 for power lines, connector pins, and limits.
Table 5-1 A50 Power Supplies
Supply Connector Pin Range
+ 5 VD TP5 + 4.8 V to + 5.4 V
- 8 V TP2 - 7.2 V to - 8.0 V
+ 8 V TP1 + 7.2 V to + 8.0 V
- 15 V TP4 - 14.1 V to - 15.5 V
+ 15 V TP3 + 14.3 V to + 15.6 V
• If any of the power supply voltages are not within these limits, replace the A50.
• If all A50 power supply voltages are good, the A50 is verified.