76 E8257D/67D, E8663D PSG Signal Generators Service Guide
Troubleshooting
Troubleshooting Assembly–Level Problems
Self–Tests 11xx: A18 CPU Self–Test Errors
1100 Power Supply
The A18 CPU self–test verifies the presence of the supplies listed. These
supplies are not checked during the turn–on check and are not necessary for
the turn–on check to pass.
1. After running self–test, View Details and see which supply failed.
2. If the 10 VRef has failed, replace the A18 CPU. The 10 VRef is generated
on the A18 CPU and used for the ADC circuit.
3. For a self–test failure other than the 10 VRef, measure the appropriate
connector pin listed in the following table.
Connector P223 Supply Voltage Voltage Range
Pin 1 –5.2 Vdc –5.2 ±.1 Vdc
Pin 17 –6 Vdc –6 ±.12 Vdc
Pin 18 +9 Vdc +9 ±.18 Vdc
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