No sound from left channel on power amp


I've got an Audiolab 8000P power amp in bi-amp mode. Just the other day, I noticed that I couldn't hear the "bass" from my left speaker. I ruled out that it was the speaker cuz I swapped them and same thing happened with the other. I checked the cables and source and ruled out that this problem was caused by any of them. So, this was the power amp I'm using for the low frequencies. I can power it up and one channel is fine. Any DIY suggestions other than bringing it in for repairs?

Thanks
poknet
There may also be rail fuses along each bank of transistors that could blow (Acurus amps are like that). Have you tried contacting the manufacturer (if the owner's manual provides no guidance)?
Careful when changing fuses, use plasic fuse pliers. Remember risk of shock even if your amp is unplugged. Also risk of shorting something and frying your amp. Im sure most everyone knows this stuff but a little reminder cant hurt.
Contact Aragon. The customer service is great. They sent me fuses for free a couple of years ago.
Thanks a lot for your input guys. The manual doesn't say much. I just ended up bringing it back to the dealer I bought it from to make the repair just in case I make matters worse. Thanks again for the advice.

Peter