Service manual

5 129
Power Supply Troubleshooting
FIND OUT WHY THE A1 +5 VD LED IS NOT ON STEADILY
5. Power Supply Troubleshooting
Figure 5-8 A1 CPU Connector Location
3. Turn the analyzer power on. Look at the A1 +5 VD LED.
• If the LED is still off, the A1 CPU is probably faulty. Replace the A1 CPU.
• If the LED goes on, the A1 CPU is verified. Continue with the next step.
4. Turn the analyzer power off. Reconnect the cables to the A1J10, A1J11, and A1J18.
Turn the analyzer power on. Look at the A1 +5 VD LED.
• If the +5 VD LED goes off, the problem may be in the analog assemblies. Continue
with Remove Assemblies.
• If the + 5 VD LED is still on, continue with the next step.
5. Reconnect the disconnected cables to their connectors one at a time. Turn the analyzer
power on after each cable is connected. The assembly related with the cable turning the
+5 VD LED off is probably faulty. Replace the assembly.
3. Remove Assemblies
1. Turn the analyzer power off. Remove the assemblies A2, A3,A4, A5, A6, A7, A8,A51
and A91J from the A20 motherboard.
2. Turn the analyzer power on. Look at the A1 +5 VD LED.
• If the LED is still off, inspect the A20 motherboard.
• If the LED goes on, the A20 motherboard is verified. Continue with the next step.