Mesa Rev F Repair Woes

  • Thread starter Thread starter TotallyRadGuitars
  • Start date Start date
Update on this old thread, I got this amp back in December and just forgot to say anything. It's been repaired by Mike B at Mesa and he did a fantastic job. According to his notes, this damage was caused by a flyback voltage from a shorted power tube, and the Mk III style transformers used on this early Rev F do not have a lead to do... something. I'm going from memory here as I misplaced the papers, but basically it said that later Rev F's and Rev G's wouldn't have this problem because the transformers are different.

I'm not willing to give up the early/og transformers, so I'll be extra careful about power tubes in this one so it doesn't happen again, but the repair looks very solid - of course. Glad to have it back and it sounds absolutely wonderful. Here's the repair spot now, to compare to before. Big melted orange colored capacitors are gone, more modern black ones in place, traces on the board repaired.... nice. Everything else on the amp checked out nice and healthy, even as old as it is, so it's still sporting otherwise original caps and components.

NFX_5912.jpg
 
Looks like they were only unable to salvage a trace or two. It looks great.
But who gives a shit…..CLIPS!! Or die ?
 
Sermo Lupi said:
It's truthfully a modern marvel that Mesa still takes on jobs like this when the world is headed in the other direction. Fantastic outcome!
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For sure.

But I read in another thread recently that Mike Bendinelli is no longer doing repairs/mods? Or did I read that wrong? Maybe it was just mods. I've read that in several places now. Was considering sending my new Dual to him but decided not to waste his time.
 
311splawndude said:
For sure.

But I read in another thread recently that Mike Bendinelli is no longer doing repairs/mods? Or did I read that wrong? Maybe it was just mods. I've read that in several places now. Was considering sending my new Dual to him but decided not to waste his time.
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No harm in reaching out to ask. I've only heard rumours of specific repairs, like people sending in Mark IIs for C+ conversions. It's elective work (and usually requested so the owner can flip a $2k amp for $10k or whatever), so I can see why Mike declines. I've also heard he's trying to wind things down for retirement, but again, I'm just parroting a rumour when I say that. This thread contradicts reports of him declining repair work (as of mid-2023, anyway).

Why not email Mesa and see?
 
Sermo Lupi said:
rumours of specific mods, like people sending in Mark IIs for C+ conversions.

Why not email Mesa and see?
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*fixed

But I know what you meant. Yeah, I've heard the winding down thing. I'm not ready to call Mesa because I'm not even sure what I want/need if anything. I just got it. :D
 
It'll be a sad day when Mike Bendinelli finally retires. His name is on the paperwork for this amp so I figure he's at least still taking repairs, although part of the reason it took a while is that he took a month vacation or something like that - well deserved I'm sure. Dang, I should've had him sign the amp!

I don't know how close he is to retirement, probably depends on what kind of schedule/salary/benefits he's getting from Mesa. In my mind he should basically be in the "name his own price" category but I doubt corporate Gibson feels that way. Also worth mentioning that this whole repair was relatively inexpensive considering the extent of the damage, and I was extremely surprised by that - $290 for parts and labor. I used Pirateship one way and they paid the return shipping. I had a Hiwatt repaired at a local shop and it was nearly $350 for one filter cap and one resistor on the power board replacement (also why I do repairs like this myself now)... the difference between a shop billing me for 8 hours bench time because they didn't know the amp, versus sending an amp like this to Mesa directly who know exactly what they are doing and can complete the repair in short order.
 
Can add I just had Mike do my IIc+ from non eq to eq and ++ treatment. Seems like it’s coming to an end pretty soon as he’s getting real specific about what he’ll take on. Typically you’ll email him directly for any of these kinds of jobs. Also supposedly I was one of the last to get the IIc+ put in a iii chassis for the eq mod as they’re out of them now. Just a rumor there though.
 
how do ya'll go about getting mike on your repairs/maintenance? I reached out them a couple weeks ago and some other dude contacted me.
 
mesa4x12er said:
how do ya'll go about getting mike on your repairs/maintenance? I reached out them a couple weeks ago and some other dude contacted me.
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He will only do VERY specific work. You can’t just call and ask Mike to do your repairs or service. Usually mods at this point from my understanding.
 
mesa4x12er said:
how do ya'll go about getting mike on your repairs/maintenance? I reached out them a couple weeks ago and some other dude contacted me.
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I called the generic Mesa repair line, so I never spoke to Mike directly at all or asked for him. I wasn't asking for anything special or custom so I prefer to just go through the proper channels rather than circumventing the process. I had a TC50 repaired at the same time (MOSFET failure) and they graciously covered that under "warranty" even though the amp is 6 years old and I'm the 2nd owner... I hope no one got in trouble for that but it was an incredibly nice gesture.

If you are just having repairs/maintenance done, just call and get an RMA# and send it in. I think you can trust Mesa to do a good job on the repair, even if you don't get Mike specifically. I do know that Mike is the only one who knows how to do certain repairs (like this Rev F) so if it's serious enough, it goes to him. If it's just a regular cap job or something, I would have no qualms about having someone else on their staff do the work, so that Mike's time is better prioritized for the more serious stuff. Just my opinion there. I spoke to Richard D on the phone a couple of times and he got everything set straight for me no problem, hassle free.

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I found the paperwork by the way. Just wanted to put this information here in case someone googles this 5 years from now and finds this thread.
Mike B's notes on the repair:

Finished rebuilding burned +/- 3 volt HTR and relay supply. This kind of burn up can happen when a power tube blows and put plate voltage to the heater winding. (Newer ones have a grounded center tap on the 6.3 winding so this can't occur. This early tranny does not have that tap.) Also the 220 ohm 5 watt resistor for the LDR supply was breaking loose. Pulled it and its filter cap and replaced it with a bigger leaded resistor.
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He also did the pots/jacks/tube socket cleaning, soldered LDR leaders, refurbed indicator LED, general cleanup stuff, which is always appreciated.
 
TotallyRadGuitars said:
I called the generic Mesa repair line, so I never spoke to Mike directly at all or asked for him. I wasn't asking for anything special or custom so I prefer to just go through the proper channels rather than circumventing the process. I had a TC50 repaired at the same time (MOSFET failure) and they graciously covered that under "warranty" even though the amp is 6 years old and I'm the 2nd owner... I hope no one got in trouble for that but it was an incredibly nice gesture.

If you are just having repairs/maintenance done, just call and get an RMA# and send it in. I think you can trust Mesa to do a good job on the repair, even if you don't get Mike specifically. I do know that Mike is the only one who knows how to do certain repairs (like this Rev F) so if it's serious enough, it goes to him. If it's just a regular cap job or something, I would have no qualms about having someone else on their staff do the work, so that Mike's time is better prioritized for the more serious stuff. Just my opinion there. I spoke to Richard D on the phone a couple of times and he got everything set straight for me no problem, hassle free.

---

I found the paperwork by the way. Just wanted to put this information here in case someone googles this 5 years from now and finds this thread.
Mike B's notes on the repair:



He also did the pots/jacks/tube socket cleaning, soldered LDR leaders, refurbed indicator LED, general cleanup stuff, which is always appreciated.
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Thanks for posting his diagnosis, that's interesting.
 
JerryP said:
The only way to fix that is to carve out the burnt sections of the circuit board and re-route any affects circuit paths. The burnt board creates a carbon path for short circuits. No repair for it but to remove it. or replace the board.
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I had a Single Recto Solo head that burned some resistors and burned the section on the pcb right below where the resistors cooked..I called Mesa and they were really helpful...I did take the complete chassis to a repair shop and they decided they didn't want to work on it..they said they don't work on Mesa amps because the resistors etc are way too close to the pcb(s) and create a lot of headaches later on down the road..

Well I told him "no shit' after driving 100 miles to drop the amp off and back home twice.. I just cut the burned part of the pcb off and used some of that Trace paint and soldered in some new resistors and the amp worked fine..but I sold it soon after that and let the guy know about the repairs done.
 
TotallyRadGuitars said:
Hello all. Back at the start of May, I jumped on a local swap shop who had gotten an early, chrome chassis Mesa Dual Rectifier Rev F - with the early "Mark III" transformers too!
So it sounds great in the shop, but I'm not playing it loud or for very long, I know I want it. So I get it home, and start rocking out, only to have all of the LED's fade out and sound goes away. A few minutes later, pops right back on no problem. Sometimes, I'll get half an hour, other times only 10 minutes before issues, and if you smack the amp on the top physically it pops back on sometimes. Ok, clearly we have something wrong, loose solder joint or etc.

So I open her up, and I find this absolute mess around R232 and R233, looks like those two resistors must've blown up, melted the cap casing next to it, and burned out a trace on the PCB too. Someone tried to repair this... poorly... by tacking on some random tall resistors (wrong values) and covering the burned trace with a small piece of metal soldered in at both ends. Botched repair job sure, but it doesn't seem insurmountable to someone with more expertise - so I decided this was one for the repair shop and not for me.

Here's a few pictures of what the trouble spot looked like:
View attachment 226375
View attachment 226381

Anyway, it's been over 2 months now, called multiple times just checking for the status and last I heard on 7/11 was that the amp hasn't even made it to the bench yet. That's not great but I get it, people are busy, it's summer, whatever. I'm really not a high pressure guy. But, I hear back directly from someone at Mesa today. Apparently, they do not have the PCB scans for any early 2-channel rectifiers, and the repair shop tried to do some kind of repair to the PCB and it ended up being non-conductive so the amp still doesn't work. I'll add some pictures of that once I get the amp back and see what they tried to do.

So a few questions. I only see one trace that is damaged. Is it really so difficult to replace that one line, and swap the two resistors to the correct value? Maybe I'm way underestimating this repair but I've watched a lot of videos online using that trace repair "pen" and other methods that make drawing a single trace line look... pretty simple? Maybe I'm just not getting it, so please someone tell me if I'm way off base here.

And my next question, ultimately they are saying this amp has to go back to Mesa Boogie for a factory repair. I am a little worried that they might replace the PCB entirely with a new one or something, which would be a hell of a kicker on the value of this amp, being Rev F and all that. Has anyone had something vintage and/or relatively rare go back to Mesa for repair? Do they respect the integrity/design of the original circuit, or will they do some unwanted updates? I'm probably worried about nothing, but what was a fair deal on a Rev F is quickly becoming the most expensive Mesa I've ever bought. I guess I'm a little frustrated (not directed at any one person in particular, maybe the original owner who did this repair) and trying to make sure the rest of the process as smooth and inexpensive as possible.

I'll have the amp back in hand tomorrow. Talking with Mesa later to schedule a possible repair. I'll update with more info as it goes.
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looks like that cap may have leaked and contaminated the board i just fixed one like that and it now works great, i showed my buddy some mod ideas and he loved the changes now its to implement via no holes in chasis.
 
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