I've just sold a Cambridge 540R AV amplifier on ebay, and the buyer has
reported a fault - the sub and centre channels don't work. I only ever
used it as a stereo amp, and never had any problem with it. In his words:
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The connection is from the DVD player – Optical lead and also coaxial
out. Both and either have been tried / and fail to produce any output
whatsoever on centre and sub. The menu provides for both to be set as on
or off and of course I have checked they are set as on and they are
still not working.
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I'm not especially bothered - we've agreed a compromise on the price -
but this seems rather odd to me. Can anyone think of an explanation
beyond broken amplifier for the fault?

Thanks, Rob