Mark IV r2 channel problems

[msteffer]

I'm wondering if anyone else has had a similar problem. My rhy2 channel quits working after a few minutes when using the switched effects loop on a 91' Mark IV. Other channels are fine, and when I use the normal loop r2 channel is fine also. I changed out all the tubes, and checked switches related to the effects loop. I took it to a repair shop and they aid they couldn't reproduce the problem. In other words, they couldn't figure it out. I thought I would try this before taking it back. Thanks in advance for any help.

 

[HalfDeaf]

I have that problem as well on my 91 mkiv revA, but I'm not sure its isolated to R2. I'll check it. When I noticed it happening, I just assumed it was a bunk component in the switchable fx loop circuit. So I switched over to the normal loop and only rarely miss the switch function.

I've had quite a few problems with my 91 mkiv, and this one hasn't floated up the priority list yet

 

[MusicManJP6]

oh man - i don't miss R2 a bit... what a hard channel to find a good tone with...