Expert: Cleggsan - 10/27/2011

Question
There was a fairly large thunderstorm last night, and while I didn't notice anything strange at the time, when I use any of the channels I get no sound  from the speakers unless its in "direct Source mode - in which case I only get 2-channel (stereo sound).
I have an Aiwa AV-D58 5.1 digital receiver. No other audio sources (TV, Phonograph, DVD) produced any sound either.  I disconnected the receiver's AC plug, disconnected all input/outputs, and disconnected the speakers ... thinking there might be a short.  I reconnected everything, and I still don't get any sound except in direct source.

All the other components work fine, and the receiver appears to be working (the LCD display works, and all the functions appear to be in working order ... volume, level adjustments, etc.)

Any ideas?

Answer
Did you check for open fuses?  I think there are a couple of solder link fuses on the inside of the receiver.  You can give them a visual by removing the cover (after you have unplugged the power cord - for your safety).

There are no patterns of failure when electrical storms go roaring by.  The only way to know for sure what may have been damaged is to have a competent technician conduct testing and troubleshooting.  It could be a voltage regulator that went bad and the dc voltage feed to the switching circuit went out. Could be a shorted cap in the power supply that killed one of the dc lines.  There are just so many possible causes.

Based on the fact most visual things seem to be working it would seem the cause may not be too difficult to find or to repair. It should not be too costly to repair if you take it to an experienced audio repair shop.

Best wishes. Let me know if there is more to the story.