Very frustrated trying to change V1 preamp tube

[The Mink]

So I assume you guys are removing the entire chassis just to change out one preamp tube? I spoke to Mesa and they basically say to do that, or take it in to an authorized tech. REALLY?

There's no way I'm going to line those little pins up without seeing them.

 

[mace]

Over the years (since 2012) I've changed a lot of V1 tubes while the amp is in chassis (head unit). Takes a bit of practice. Somehow I broke only one in all these years when getting that long tube shield put in place. A few pins have been bent, but they weren't too bad and could be made straight again. Basically, use your finger to feel where the gap in the pins are and line that up towards the front of the amp as you contort your arm in there. Push gently so you don't bend pins if things are misaligned. Yes, it is a pain, but possible.

 

[user 21540]

I'm not familiar with the Mark V layout but are you able to turn the amp upside down and use a torch and/or a small mirror?

 

[Petit scarabé]

You can use your phone to see the socket.

 

[Appleridge]

The pins on the others will be in the same orientation. I use those as a reference when holding the V1 tube, then I go in lol. It still a pain, but I have an idea as to where the pin gap should be.

I can’t remember if you can go in the front, but pop the grill off and check? Easy enough if you can.

 

[bandit2013]

The Mark V90 is a pain to get the V1 replaced. When it came to preamp tube issues, I would normally remove the chassis from the head shell. I did not have an issue with the tube install, just getting the damn tube shields back on was more of an issue. Before I converted my V90 from a head to a combo amp, I replaced the long tube shield on V1 with a normal short one. Much easier to get my hand in there and get the socket installed over the tube. When I decided to remove the chassis, I just left the power tubes in their place along with the cage. Figured out how to adjust the tensioner post just enough before I can turn it by hand. Chassis removal was still tricky but took far less time to remove that vs struggling with getting the preamp tube installed. My hands are too big to fit. Faceplate as I recall did not have an access cutout behind it like the JP2C has (with that amp you cannot reach the preamp tubes with any ease unless your hands are the size of a child.

In combo format, No struggles, It was much easier to lay the amp down and work from there.

 

[steve Rhenius01]

The pins on the others will be in the same orientation. I use those as a reference when holding the V1 tube, then I go in lol. It still a pain, but I have an idea as to where the pin gap should be.

I can’t remember if you can go in the front, but pop the grill off and check? Easy enough if you can.

You can do as suggested on the V5 90 head. I remove the chassis to work but that’s probably overkill. These ‘Swiss Army’ amps are over complicated and unnecessarily complicated to service, especially in the field. I think this a result of hiding assembly cost and passing it downstream, presumably to increase sales, but this damages the brand and leaves them open to informed competition. Difficult choices in a cut throat world !

 

[jsullivan2112]

You can do as suggested on the V5 90 head. I remove the chassis to work but that’s probably overkill. These ‘Swiss Army’ amps are over complicated and unnecessarily complicated to service, especially in the field. I think this a result of hiding assembly cost and passing it downstream, presumably to increase sales, but this damages the brand and leaves them open to informed competition. Difficult choices in a cut throat world !

It’s much simpler than that. It’s because they wanna cram it all into such a small space. That’s how Marks started to begin with, now it’s a running joke.

Nothing wrong with a complex amp, it’s the real estate that’s the issue.

 

[gibsonboogie]

On my V35 head, I found it much easier to remove the front panel of the amp to access V1-V3. It's attached with 4 screws , comes right off and goes right back on without issues.

 

[domct203]

100% Agree. Most later model Mark owners do that.

 

[shawnohio]

So I assume you guys are removing the entire chassis just to change out one preamp tube? I spoke to Mesa and they basically say to do that, or take it in to an authorized tech. REALLY?

There's no way I'm going to line those little pins up without seeing them.

you look at how they are lined up when you take them out. If you already took V1 out then take V2 out, slowly, and note the location of the gap between the pins. The sockets are usually installed in about the same orientation, so after putting V2 back by pre-lining it up with the orientation of the gap (the gap is usually pointed toward the front or back of the chassis, but sometimes a different angle) just gently wiggle it into place. Then put V1 back in using the same orientation that you found with V2. It takes a little practice, but soon you'll be rotating and swapping them all out with ease. The hard part will be leaving them alone lol.

 

[cgscotto]

I have changed V1 on my MKV many times without removing the chassis. As stated on the JP-2C and MKVII, you can remove the front panel to get easier access to V1, but that does not work on the MKV head.

Here is what I do:
1) remove power tubes
2) turn the head upside down. This make aligning the pins easier and you can get that long shield tube back on more easily.
3) withh the head upside down, the gap in the pins is towards the front (I doing this from memory, so best to varify before shoving a tube into the socket.)
4) rest the tube in the socket and lightly rotate back and forth. If you are holding the tube lightly, it will drop a bit when the pins are aligned (having the head upside down helps this process)
5) once tube is aligned, push to seat it.
6) replace long tube shield (also way easier with the head upside down).

HTH

 

[tbonesullivan]

I guess this is one time I can Flex about having bought the combo and not the head? But I definitely understand, as I also have a good number of heads, and Mesa does not leave much room in their Mark series heads, not compared to the huge heads from other companies that leave tons of room.