Mark V Channel 2 Problem

[Millers]

Hi all, I'm wondering if anyone can help me with my problem?:

Mid-week I was playing on channel 2 and the volume drastically dropped to a very low, just about audible volume however it's extremely quiet in comparison to channels 1 and 3 which still sound great.

I reported this to Boogie who suggested I replace the V2 preamp valve 12AX7. I ordered a new genuine Mesa 12AX7 valve and replaced it with V2 however this hasn't resolved the issue.

I proceeded to replace each of the 7 original 12AX7 with my new one however still no joy.

I've also swapped V1, V2 and V3 with V4, V5 and V6 wondering if the problem might move to a different channel however still exactly the same problem.

The problem on channel 2 is apparent in all modes at all wattages. Channels 1 and 3 function normal as good as new in all modes at all wattages. Does this eliminate any of the 6L6 power tubes or the 5U4GB rectifier tube as the root cause?

I've had the amp since 2011 with no previous issue but haven't changed any of the preamp or power tubes before.

Please can anyone help with this problem or offer any advice in fault finding?

Many thanks

Nick

 

[bandavet]

EXACTLY the same problem here. Did you managed to get it fixed?

Peace,
Edu
----------
2011 Mark V combo
1986 Mark III head

 

[OryCheyne]

Have you tried direct channel selection without the footswitch?
Just an idea.

 

[bandavet]

Ory

Yep. I've tried without the foot switch, no success.

Peace,
Edu
----------
2011 Mark V combo
1986 Mark III head

 

[Karl Houseknecht]

I'm also curious. Buddy of mine has this same problem. Anyone get it remedied?