Amp heats up and shuts off - Help!!

[jeskibuff]

Yes, the Yamaha does have A and B speaker outputs with a front panel selector for either or both.

So you play both sets of speakers at the same time? If so, you're giving your Yamaha a REALLY tough load...by my calculations, about a 2.67-ohm load. The Yamaha may be able to take it, but it might be running pretty hot.

I connected my computers sound card out to the Yamaha (Tape In) - and I used to get the sound from just the right channel speaker and that too at very low SPL compared to the tuner or the DVD, while the left channel speaker just gave a constant irritating hum.

This sounds like a connector problem to me. What kind of connector are you using? Is it just one cable with a mini-phono plug at one end and two male RCA plugs on the other end? Is it a combination of cables and a "Y" adapter?

This led me to connect the sound card out to the powered sub of the altec lansing and use the sattelite speaker out to connect to the Yamaha (since the altecs dont have a pre-out).

You don't want to do that. The output level of the Altec should be too high for what your Yamaha is expecting.

I hope I am not going to blow up my Altec powered sub in trying all these permutations and combinations with the sound.

The Altec has nothing to worry about. Your Yamaha IS vulnerable to damage, though!