Mark IV - Full Service Tune-Up

[SonVolt]

My Mark IV was built in 1996 and has started to experience some common signs of wear and tear. I think it's time to send her in for a full refresh. I won't be sending the amp back to Mesa, but will be sending it to a local authorized Mesa repair tech in Nashville.

I'm experiencing the following issues (some copied/pasted from search results) -

1. Volume drops/swell and sudden changes in EQ
2. Blinking/dim/not working LEDs
3. Odd noises - intermittent "wurring", or it sounds like an open mic in the wind.

Is there anything specific you would ask them to do with the amp? I've read about LDR issues with these amps. Would you ask them to replace all LDRs? They said they would on request, but that they are hard to get and this would be expensive. I just want to make sure that everything gets done that needs to get done while they have the amp open. I'd hate for them to replace an LDR that fixes the dim LED issue, but have another LDR break 6 months from now etc.

 

[kmanick]

If you love that amp and plan on holding on to it , Id' just send it to Mesa
I recently picked up a very early transitional "B" head and I am going to send it out to Mesa for a full refresh as well. The caps have already been done on mine but I don't know how the LDLs/relays are and the work was not done by Mesa (done before I bought it ). I'm holding on to this one (my 3rd one) so I just think better safe than sorry.

 

[electric mayhem]

My Mark IV was built in 1996 and has started to experience some common signs of wear and tear. I think it's time to send her in for a full refresh. I won't be sending the amp back to Mesa, but will be sending it to a local authorized Mesa repair tech in Nashville.

I'm experiencing the following issues (some copied/pasted from search results) -

1. Volume drops/swell and sudden changes in EQ
2. Blinking/dim/not working LEDs
3. Odd noises - intermittent "wurring", or it sounds like an open mic in the wind.

Is there anything specific you would ask them to do with the amp? I've read about LDR issues with these amps. Would you ask them to replace all LDRs? They said they would on request, but that they are hard to get and this would be expensive. I just want to make sure that everything gets done that needs to get done while they have the amp open. I'd hate for them to replace an LDR that fixes the dim LED issue, but have another LDR break 6 months from now etc.

Ah, it just sounds like an ET encounter. Give em chocolate chip cookies and send them on their way.

After a recent experience with a rectoverb I would tighten all the power tube pin sockets to see if that makes a difference on the cut out. It wouldn't explain LED's going haywire so it would be just trying to reduce the list of problems.

As for Mark IV service a reliable person on here says the factory is done working on them. Mike is about caught up right now so the timing could be right to sweet talk him into it but it sounded like a hard stop as opposed to "officially" having stopped the mods.

 

[SonVolt]

Ah, it just sounds like an ET encounter. Give em chocolate chip cookies and send them on their way.

After a recent experience with a rectoverb I would tighten all the power tube pin sockets to see if that makes a difference on the cut out. It wouldn't explain LED's going haywire so it would be just trying to reduce the list of problems.

As for Mark IV service a reliable person on here says the factory is done working on them. Mike is about caught up right now so the timing could be right to sweet talk him into it but it sounded like a hard stop as opposed to "officially" having stopped the mods.

Mike sent me an RMA number so maybe the timing was right. I'm going to send it back to him for a full fresh.

As far as "mods"... what type of mods were people sending the IV back in for?

 

[electric mayhem]

Mike sent me an RMA number so maybe the timing was right. I'm going to send it back to him for a full fresh.

As far as "mods"... what type of mods were people sending the IV back in for?

Idk of any mods for the IV. I think the Mark had evolved enough by IV to have worked out the kinks and map a new trajectory.

The rage the last few years has been an attempt to turn Mark III's into either a IIC+ which they'll never be but seemed more like a fix and flip income generator, or into a high high gain trick pony squeezing every bit of gain out of the turnip (++ mod) instead of having a more versatile amp and use a pedal to taste. I won't be sad when these mods stop.

There is the IIC to IIC+ mod which has followed the fix and flip mentality and Mike charges accordingly while the market price of a IIC+ still seems to be dropping. This mod does serve a purpose even if the flippers get squeezed out since unlike the III's this mod is the real deal if someone wants a plus.

The other big one is the IIB loop mod. For the 1st time since I've been watching boogies the IIB is gaining interest. Luckily there is a ton of them out there. The loop mod is a game changer but if you have a tone monster IIB not loop modded it will not come back the same. Mike also updates the non-SP/RP-9C pre board to 9C specs which leans towards higher gain tightness and rolling off the low end a little on a V4 cap iirc.

Thanks for the heads up on IV service at the factory. I'm sure you're not the only one to want factory service.

 

[kmanick]

I spoke to Rich last week and he was ready to send me RMA for my mark IV as well, I think they are ok with doing the "once overs' he asked me if I wanted it returned to 'stock" as in all caps/LDL's etc. I just don't think Mike does all of them anymore and maybe "mods" are off the table.

 

[electric mayhem]

Officially the mods are off the table and as he stated to me, he alone decides if he does a mod.

That said he is converting 2 Mark IIC's (D&S power) that needed service anyway (I still have 2 stock IIC's, one S with exceptional tone), and also doing loop mods on a pair of IIB coli's for me atm. He just got the ATOM's I sent him this week.

If this interest in IIB's continues I would expect a lot more loop mods heading to Petaluma. I know I plan on having him do another B or 2 and if I can find a OG and IIA that need service on the cheap I'd like to have him do a loop mod on each of them if he's willing.

 

[Appleridge]

He just got the ATOM's I sent him this week.

Morning! Regarding the IIb, sounds like you are sending in your own caps? Mike has mine at the moment. I emailed him asking if he would like me to send in option caps. In your opinion, the stock Mesa currently uses isn’t great, or just personal pref?

Regarding the IV, they did a great job on my “return to stock” job. Just be specific on what you want (all LDR’s or specific LDR’s). My III will have to go back due to me not being specific.

I sent one in the had a clear volume swell going from ch1 to ch3. I referenced this and assumed all LDR’s would be checked. They only repaired what I referenced which is my fault. When my II comes back I’ll prob send the III back in to repair the rest. Again, this is my fault. I imagine they have a repair ticket and do exactly what it says on that ticket. No more, no less. Either way…send it! Mike B had me take pics of my IV before he agreed to “return to stock”. Apparently there are some caps that are prone to leaking in some IV’s. Once they start, he won’t touch.

I would send to Mesa for sure. It gives piece of mind to the next owner should you sell. Local techs are great im sure, but to the wary buyer, paperwork and evidence of a mesa once over carries more weight imo.

Good luck!

 

[kmanick]

Morning! Regarding the IIb, sounds like you are sending in your own caps? Mike has mine at the moment. I emailed him asking if he would like me to send in option caps. In your opinion, the stock Mesa currently uses isn’t great, or just personal pref?

Regarding the IV, they did a great job on my “return to stock” job. Just be specific on what you want (all LDR’s or specific LDR’s). My III will have to go back due to me not being specific.

I sent one in the had a clear volume swell going from ch1 to ch3. I referenced this and assumed all LDR’s would be checked. They only repaired what I referenced which is my fault. When my II comes back I’ll prob send the III back in to repair the rest. Again, this is my fault. I imagine they have a repair ticket and do exactly what it says on that ticket. No more, no less. Either way…send it! Mike B had me take pics of my IV before he agreed to “return to stock”. Apparently there are some caps that are prone to leaking in some IV’s. Once they start, he won’t touch.

I would send to Mesa for sure. It gives piece of mind to the next owner should you sell. Local techs are great im sure, but to the wary buyer, paperwork and evidence of a mesa once over carries more weight imo.

Good luck!

yes I already sent them the pics of mine just need to come to grips with it being away for a few weeks (separation anxiety) LOL!

 

[electric mayhem]

Morning! Regarding the IIb, sounds like you are sending in your own caps? Mike has mine at the moment. I emailed him asking if he would like me to send in option caps. In your opinion, the stock Mesa currently uses isn’t great, or just personal pref?

The factory is using IC 47uF filters to replace the 30uF ones. With ATOM's being the gold standard I ordered a bunch of 30uF. I got 2011, 13 and 17 batches and the 17 batch are all testing out of spec at 37uF. At the price they want for the remaining ones out there I wouldn't have bought them had I known the situation. The same for some ATOM 40's I bought from 94.

For a long time the factory was using the BMI's which were cool because they have the MESA logo and are dark blue but while many of them tested good there were outliers in the batches that didn't get QA'd out and I wouldn't want in my amps. The BMI's are no longer available.

Before that timewise was Chemi-con which I don't see any 30uF's around.

So after the ATOM bad batch of chemicals shutting down production it seems F&T is the last 30uF standing from a known historic quality view. There are JJ, TAD etc out there putting their name on filters but Idk anything about them.

I will say that I bought 66 IC 220uF's to start going thru some M180's/M190 and check my 2:90's. IC historically isn't a gold standard but after testing over 30 caps the consistency QA or off the line was exceptional. I wanted to buy IC 30uF/500V only to find they don't exist. Surprisingly they don't even seem to make a 33uF/500V.

As for the IV it sounds like there is a screening process. Anyone with the brown 10k sprague caps that aren't leaking should take advantage of the window to get them removed. The 8200uF ones and the IC 10KuF aren't known to leak.