Pioneer Amp Err Problem

[Dan2001]

I have a Pioneer VSX-D912 that was damaged in a lightning incident. I've tracked down the problem to the internal DC detection bus being activated. This would happen if an amp blew and the output had a DC component. The same bus also is driven if the cooling fan is inoperative.

Every amp output is at zero volts with no signal, so I believe it is the fan STOPPED detection that is pulling down the DC error bus. The fan is not turning which seems to be required to keep it from pulling an error condition. The fan circuit is complex with all channels being sampled and rectified to drive the fan with variable speed.

My conundrum is should the fan be turning even without any audio signal applied? It seems that it should to keep the fan stopped detection from kicking in. Anyone have experience with this?

 

[Seth=L]

The fan will not turn on unless the amplifier is producing enough heat for it to do so. This keeps the receiver from making noise when there is no ouput. The fan is almost not necessary in that receiver as it doesn't produce enough heat at moderate to higher levels to turn on, it would have to be cranking pretty good for it to kick on.