Mark V Channel 3 problem

[jbm1122]

I recently got my Mark V Combo. and Just This morning Channel 3 stopped working, All the gain and volume is lost and sounds like a clean channel with all volume rolled off on a guitar. I was just wondering if it is definitely a pre amp tube problem? and if so should i try any other types to replace it with? or replace all of them instead of one?

 

[shogun]

i had this happen and it was a bad preamp tube.. i forget which i changed, but it was an easy fix

 

[captainmark777]

I had the exact same problem last night! Anyone know which preamp tube/tubes to change. Thanks.

 

[mejoshee]

if ch1 and 2 still work then it's likely v4-6. if the reverb is also not working then it'd be 4 or 5. if the effects loop is not (instead of the reverb) then it's v6. if neither are working, well you need to replace at least 2 tubes now. if you really still can't figure out how that all works, take it back in the dealer and have a chat with them.

refer to pg. 62 in the manual:
http://www.mesaboogie.com/manuals/MkV_100303.pdf

read the whole freaking thing. this will get you the most out of the v. it's not a complicated read if you've seen a mesa manual before. if you haven't, well, grab your snuggie and curl up for a bit of tone-geek goodness.

cheers on your new purchase! welcome to the club! 8)

 

[jbm1122]

Thank you The reverb and the effects loop still work .. so could it be something else?

 

[jbm1122]

and also do i have to replace it with the mesa 12ax7 or can it be a different type of 12ax7?

 

[eudaimonia02912]

Mesa requires you to use their tubes to maintain your warranty. But you can use pretty much any 12AX7 you like. Just make sure to swap Mesa tubes back in before you bring it in for a warranty repair, if you ever do that.

 

[mejoshee]

Thank you The reverb and the effects loop still work .. so could it be something else?

i guess i should've been clearer. it's entirely possible that only 1/2 of a given preamp tube failed because there are 2 separate sections in the same envelope (tube).

do you have a spare one? if you're going to have to go down to the music store anyway, you might as well have them check it out at the same time. that'll narrow it down for you and if they're legit then they'll only charge you for the tube(s) you need. good luck.

 

[jbm1122]

Thanks for your help I will do that.. I might even try a spax7-a in the V1 while i'm at it...apparently it is supposed to improve the sound a fair bit

 

[jbm1122]

so I have gotten around to buying a replacement 12ax7.. and i took v4 out to put the new one in.. but can not for the life of me get it in! there is no way i can line the pins up because i can not see where the go in the amp at all... any tips?

 

[SteveO]

so I have gotten around to buying a replacement 12ax7.. and i took v4 out to put the new one in.. but can not for the life of me get it in! there is no way i can line the pins up because i can not see where the go in the amp at all... any tips?

The preamp tubes are all oriented the same, just pull out one of the tubes next to it to check pin orientation. They are indeed a bugger!

 

[boogieboy]

My channel 3 died last night, right in the middle of playing-less than a month old. Just got a steady low buzz out of it. 1 and 2 were fine, so I changed tubes 4-6 because I had three there and didnt feel like pull power tubes, changing one, put power tubes back etc. Shutgun approach worked. Back to gainy goodness. Not a fuzzy warm feeling though.

 

[sean106alcon]

so I have gotten around to buying a replacement 12ax7.. and i took v4 out to put the new one in.. but can not for the life of me get it in! there is no way i can line the pins up because i can not see where the go in the amp at all... any tips?

I found the easiest way to change the preamp tubes is 1 Obviously take out the power amp tubes and get a little flash light so you can kinda see the pin holes; make sure they are lined up with the tube and go reaaaaaaal slow until it pops in easily. Hope this helps.