Mark V Clean Channel Cutting Out - Help!

[alexvaleriev]

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!

 

[Authorized Boogie]

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.

 

[alexvaleriev]

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.

 

[jb's 52]

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"

 

[alexvaleriev]

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."

 

[jb's 52]

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."

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

:jb

 

[alexvaleriev]

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

 

[Drexter]

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

 

[jb's 52]

Cool!

Glad to see the fix worked for you too!!