Distortion in the right channel

yep: a $175 trip to Rita/Bob's repair/refurb shop!
But no sorry; can't help other then suggest get the service manual and see what adjusts the 55 has and try and do 'em (and perhaps clean some pots, etc.). I've become an "expert" at doing these on the 45, but was told that the 42/45 was unique in at least one of these (the "damping" adjustment which I'm about to hopefully fix once and for all with the "drift/fix" SB update for that one!).

Welcome azstars2004

Welcome azstars2004! What kind of distortion? Try to describe it for us. Could just be a bad connection.

Give it a whack on the right side. If the problem continues, send it off for repair.

Give it a whack on the right side. If the problem continues, send it off for repair.

...from the Arthur Fonzarelli school of audio repair...

do you repair your tube amps that way, Jesse?!?

You know, back when I was a young prick (as opposed to being the old prick that I am now ) I had this brand new Kenwood receiver in which one channel stopped working a week after I bought it. I checked that damn thing out from top to bottom and could not find the problem, so out of pure frustration I picked it up about 2 inches off of whatever it was sitting on and dropped it. The channel came back on and still worked perfectly when I got rid of it.

Give it a whack on the right side. If the problem continues, send it off for repair.

In the IT world, this procedure is pretty much a universally known (but "off book") repair method with big Cisco routers and Windows server boxes when they get inscrutably wonky.

The technical term for this procedure is called "percussive maintenance". I've used it to great effect. I used to have a Technics receiver that I bought in college that had a dicey left channel, and once every year or two it required percussive maintenance, and the channel would come right back.

I once saw an IT tech in a facility which I'm not at liberty to name, perform percussive maintenance on an entire rack of massive-parallel-processing Linux boxes because they had some sort of Ethernet weirdness going on. They had tried everything else unsuccessfully for 2 days to get it working again. He picked up the corner of the rack and dropped it so hard it actually dented the linoleum. After a hard re-boot, that particular rack ran, error-free for over 10 months continuously, and only had to be shut down because they were adding more processors and had to reconfig and reboot the whole system...

[DaveS]

We used to hit the side of our TV to make it work when I was a kid. That was one of the nice things about tube stuff, cheap fix.

My TL-3100 drops the left channel occasionally, and a quick rap on the right side brings it right back. You must be firm with used quality audio componants. Their previous owners probably spoiled them.

I'd check the connection terminals for your IC's. Sometimes the mounting nut inside the case gets loose breaking the ground circuit. Swap cables too as they do tend to break after much use.