Mark V Clean Channel Cutting Out - Help!

Hello guys! I have this weird problem with my Mark V: https://youtu.be/xtcdL3eodXE
When going from the 3rd to the 1st channel, sometimes I get this kind of big volume drop, It cuts the signal almost completely. The sound comes back when: I strum really hard on the guitar, change the mode from Fat to Tweed and back or push the stand by switch and bring it back. I think the problem is in the preamp, because there's sound when I plug the guitar in the Return and when going back to the main input, there's still no sound. I tried changing all the tubes one by one, but the problem is still there. Any ideas? Thanks!

Have you tried exercising the rotary switch on the back of the amp? Sounds like it may be oxidized and needs cleaning. Sounds strange, but I've seen it a few times now and is something easily over-looked.

Thank you for taking the time to reply. I'll take a look, but I think the problem might be somewhere else, because the same thing happens, when I'm using the footswich. I really don't understand why the sound comes back when I strum the strings really hard.

Yep...relay switch...

I had the same issue seen here (with and without bypass):
https://youtu.be/-41mAFh-xDk
https://youtu.be/wtQrx93XwjA

I had to send it to Mesa for repair.
Repair notes state:

"Replaced relays RYC3E and RYC1C. They are in series between 3rd and 4th CH1 stagers. 1 of the[m] was hanging / sticking"

Thank you very much! I really appreciate it! I'll give the amp to a tech and we'll check/replace them.
Ps. I can not see the videos. " Video unavailable This video is private."

alexvaleriev said:

Thank you very much! I really appreciate it! I'll give the amp to a tech and we'll check/replace them.
Ps. I can not see the videos. " Video unavailable This video is private."

Click to expand...

No worries. I hope you get this resolved.
The videos should work now, let me know if they don't.

:jb

We changed the two relays and everything works perfect now. Thank you so much for the help! )

Same thing happens to me, i asked here some time ago about this, but its awesome that now i know were to look at, the weird thing with my amp is that only does this when lets say you don’t play the amp that often, anyways thanks

Cool!

Glad to see the fix worked for you too!!