[Soundbitten]

I have a Nad amp , Marantz and Realistic receivers and they all have the same problem . They are all at least 25 years old .  They'll all play fine for a while then unexplicably one channel will quit ( it's always the same one ) and then come back . With the Nad it works if I pick up the front of the amp and drop it gently . The rest of the associated gear ( speakers etc. ) operates fine .
Would anyone know what the problem could be ?

Thanks

[Scott F.]

Does twisting the volume pot or balance pot (violently) make the channel come back?

If so, chances are they are just dirty. If you aren't comfortable working on an amp, a local service tech should be able to clean them for you for minimal dollars ($50 or so). If you are comfortable, get some 'tuner cleaner' from Radio Shack and clean the pots yourself.

If twisting the pots doesn't do it, better take it to a tech so they can check it out. It could be a number of things causing the channel to drop out.

One other thing, as I reread your post you mention that you have an NAD AMP. I assume you are using this with a separate pre. If your source is a CD, turntable (or anything other than the tuner), the problem may be with either the source or maybe even a bad interconnect. Try swapping interconnect cables between the two channels and see if the problem follows.

[nbourbaki]

It may be your output relay.  When you turn the recievers, do they make an audible click after a second or two?  That clicking is the sound of the relays engaging.  What model is the Marantz?  What I had to do with my Marantz 4270 was pop the clear plastic covers off the output relays and using heavy paper soaked with DeoxIT, pull the paper between the contacts on the relay.  I haven't had any problem since, worked like a charm.  It used to drive me nuts, I'd be listening and one channel would cut out.  I tried cleaning the pots, the tape switches without fixing the problem.