Pioneer SC-37 Service Manual page 61

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Amplifier Diagnosis with Current Applied (2)
When the remained switching waveform is not observed in the speaker output, the amplifier is not operating.
Here, confirm that the power and signal necessary for the amplifier to operate are supplied.
Is the modulator IC
power ±5V supplied?
(Pins 1 and 3 of CN4902)
Is there disable
control signal? (Are pins 1 - 4
of CN4000 set to H?)
Is the
driver power supplied?
(About 10V between the pins 1
and 2 of CN4901. Note that
it is not based on the
chassis)
Does the
output stage power
TE
L 13942296513
±64V supplied?
(Pins 1 and 4 of
CN4900)
Perform Amplifier Diagnosis
without Current Applied
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No
Check the path (cables and connectors) of ±5V.
Yes
No
Check the path (cables and connectors) of the disable signal.
Yes
Diagnose the driver power circuit. (It is highly suspected that there is a failure in
No
the power amplifier upon the power failure. Also, diagnose the amplifier circuit by
Amplifier Diagnosis without Current Applied.)
Yes
Diagnose the power circuit in the output stage. (It is highly suspected that there is
No
a failure in the power amplifier upon the power failure. Also, diagnose the amplifier
circuit by Amplifier Diagnosis without Current Applied.)
Yes
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