Just picked up a NAD 7140 stereo receiver for free with some speakers I purchased. I got it home, plugged it in, hooked up some speakers and an antenna and no sound. Played with it for awhile and noticed the AM/FM button was sticking. Cleaned the contacts on that and now it tunes in the radio but here is the strange part...

In STEREO mode the right channel almost sounded blown in both A and B selections. On closer examination I noticed that while the right channel(s) are producing sound it is as if the mid to lower bass frequencies are chopped off... only the highest mids and highs are present. The left channel(s) work as expected. I tried swapping out the speakers, the wires, and tried different FM channels with the same results.

Here is were I am a bit baffled... When I hit the MONO switch both speakers work great, albeit not in stereo! So what's the deal here? If it was the output section of the amp shouldn't stereo/mono make no difference? I suspect it's directly in the FM tuning section but can't for the life of me figure out why it would be channel dependent... of course I am no radio technician either!

Tips? Theories? Similar experiences? A good radio repair shop in the Puget Sound (Washington state)?

EDIT: Just hooked up a CD player to it and both channels work great so it's obviously a problem with the FM section?

Thanks in advance!

the switch could be dirty ... beyond that i'm afaid i cant help.

I'm with dingus, clean the switches, do the mono and the am/fm button, while you are at it clean all of the posts and switches for good measure.

Jim

Also, clean the tuner trimpots. NAD used the cheapest trimpots and they easily corrode.

Also, look for some broken solder joints or a bad ceramic cap. Nad use to have those in FM section of older units.
BTW, did you tried with another antenna cable? IMO, i found some FM cables to work great with some receivers, and very bad with others.