Keysight Technologies E8257D Service Manual page 33

Troubleshooting
Troubleshooting Assembly–Level Problems
Figure 1-1 Pulsing Activity
5. If all the signals measured in Step 4 are good, go to Step 6.
6. If all the signals measured in Step 4 are good, check the following signals
E8257D/67D, E8663D PSG Signal Generators Service Guide
The pulse state signals are control lines, clock, and data for the LCD.
500 ns
If any of the signals measured in Step 4 are bad, check the following
signals at P221 of the motherboard:
Signal
P221−14 VLCD
P221−53 LCD_ENABLE_H
P221–1 to 13, 15, 41, 43, 45, 47, 49 to 52
If any of these signals are bad, change the CPU board.
at J9 of the power switch. To access J9 the front panel must be removed
from the chassis frame and laid face down.
Signal
J9−7 VLCD
State
approximately 21 Vdc
>3 Vdc
Refer to
State
approximately 21 Vdc
Figure 1-1 on page 33.
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