AMT Datasouth Accel-7350 Service Manual page 93

(First, check 40V-generating circuit, because +5V is regulated from the 40V
output.)
If using a "X100" attenuator built-in probe, check the waveform at 200KHz
frequency between the drain of P1 and primary GND (heat sink panel of P1).
Else check all following possibilities.
P1 OK?
• Check the resistance between the drain and source of P1. Make sure
it is not shorted.
P1 OK?
Check the waveform at pin 3 of P1.
R4, R5 OK? If not, replace.
SCR1, SCR2 OK? If not, replace.
PC2, Q1, ZD2, ZD5, ZD4, R19, R20 OK? If not, replace.
If still no 40V, consult your dealer.
F2 fuse, P2, ZD3 OK? If not, replace
If no +5V, check FB3.
If still no +5V, consult your dealer.
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