Problems with my Tri-Vista 300--Need some help

Thanks a lot, chris. I'll see what I can do.

Pop the top and check for a loose RCA cable connection inside. MF uses quite a few of these internal cables in the Tri-Vista and one could have come loose. Overall, MF gear is some pretty reliable stuff with very good customer service.

Thanks Merganser. I really like the amp and want the problem fixed. I tried contacting MF by phone and they're hard to reach these days--probably because of the holidays. Are there any other ways to contact them other than the one phone number posted on their website? Thanks.

Email sent.

This has gotten quite ugly. I took the amp in for repairs to a shop in the electronics market here that handles all kinds of brands. I just got a call last evening with some very bad news. It seems that two of the six trivistor tubes used in the amp have gone bad already--only a bit more than a month after my purchase and brand spanking new. He also said the source selector wasn't working properly and would need to be replaced, but naturally he doesn't have spare parts for the machine because trivistor tubes simply aren't floating around. These tubes are supposed to last twenty years! How could they go kaput in only a month? What am I to do?