mjmurphy61 wrote: 
So, it looks like you have non-powered speakers in the living room, the line level outputs of the Airport Express go to the line level inputs of the HK, which drives the speakers.  If you got powered speakers, you wouldn't need an amp.

What are the speakers you're using in the living room?  It may be a shame to replace them because of an amp problem.

Before totally giving up on the amp, sometimes an application of contact cleaner like deoxIT on switches and controls can restore a bad channel.  And the tape monitor switch is important, even tape deck isn't in the system.  If that control doesn't work right, it can stop the music.  Sometimes just flipping/rotating the switch re-establishes contact.

If it's a blown output transistor, there are all kinds of Chinese fakes out there as bogus replacements. 

As for powered speakers, if you hang around Radio Paradise, it's AudioEngine A-2's or A-5's.  All the writeups and opinions I've seen on them have been very good, though I've never heard them in person. 

 mjmurphy61 wrote: 
I would recommend an hour w/ a screwdriver set and a multimeter. I'd start with the speaker connections, and then move to the inputs. just check continuity between the posts and the landings inside the receiver. You might find something that $0.05 worth of solder will fix.

Then go hit the used audio places like Milo suggests.

 mjmurphy61 wrote: 
One to two hundred dollars gets you some killer stuff from the same era as your HK380i. I personally prefer the two generations of HK gear that came before yours. You can get HK330, 430, 730 for 50-150 bucks relatively easily. Heck, if you're patient Marantz gear can appear in your life for similar prices. My dad actually had the exact same thing happen to the exact same amp and went backward to a HK430 and is very happy. I run an HK730 downstairs and a Marantz 2245 upstairs. Nothing you can buy now for $1-200 will last anywhere near 30 years or sound nearly as good.

Yay, my trusy Harmon Kardon HK380i tuner/receiver/amplifier circa 1979 just lost it's right channel. I was using it in my living room streaming to an Apple Airport Express, so RP is currently playing though one speaker. Got a good 30 years out of that sucker!

Now I get to go audio shopping. Oh yeah. Wait a minute, I'm broke! Well not totally, can anybody reccomend an inexpensive powered speaker system. I've been kind of looking around lately and so much is surround sound stuff that I'm just not into. I just want something in the 1 to 2 hundred dollar range that will do the job. I'm using a pair of Edirol powered speakers in my bedroom that sound great, but I'm not sure I wan't two pair of those, besides those are more studio monitors (near field) than I would like for the living room.

Anybody using anything that they love?