Need help IDing this amp.

[CRobbins]

I just picked up this Boogie amp.It's gonna need some work, but I got it for almost nothing It is a MK II. But is it an A, B, C?
I can't seem to find a users Manuel for a MK II A. Any thoughts appreciated.
Thanks.

CRobbins

 

[s-fresh]

It's hard to read that serial, but based on the Send/Return I would think that is a IIB.

More info here on the serials for each model/year:
https://mesaboogie.zendesk.com/hc/en-us/articles/218914817-When-was-my-amp-made-

 

[CRobbins]

S# is 5409
Late 1978 - Aug. 1980
3000 - 5574

 

[woodbutcher65]

Export/worldwide mid to late run Mark IIB. Slightly modified, presence control missing. The existence of a labelled effects loop identifies it as not being an A version.

My Mark IIA had serial number 3116. I'd buy it back if I were ever to find it. That'd be, officially, the 116th Mark II off the production line.


The tube chart references the fetron. So that's a leftover from the A version days. They just used those charts until they ran out of them.


I'd restore it to its original condition with presence control and, if it had it, reverb. Which, based on the circular smudge, it did.

Why anyone would remove the reverb and presence controls is very much a mystery to me.

 

[CRobbins]

Thanks........

 

[CRobbins]

I wonder why someone would remove the reverb, and presence controls?

 

[CRobbins]

So I've had this amp 2 days now, and here is what I've found. I plug in the guitar, turn up Vol. 1 to 7. Turn up Master Vol. to 3, and get no sound. I only get sound when I turn up the lead drive. Clean, and loud. The treble, middle, and bass controls work, as does the EQ. The lead master has no effect on the sound. Here's what I found after removing the chassis. 2 preamp tubes missing, and the lead master disconnected. Is this a hack job, or some kind of mod?

 

[CRobbins]

 

[woodbutcher65]

It's definitely not in stock form. The presence and reverb have been messed with, some other things are out of place, and of course, with two preamp tubes missing, it doesn't have ANY chance of being fully operational until you at least replace them.

I'm betting that the filter caps (big blue ones) are all original, in which case they're about 25 years overdue for replacement.

 

[woodbutcher65]

Here's a good photo of a pristine example to use as a reference. Anything that is different is suspect.

Note that this example doesn't have an EQ. That's OK. It just makes it easier to use as a reference for everything other than the EQ.


I would seriously suggest that you have this amp restored to its original state. When you don't know what's been modified, it's best to remove the mods and start from the beginning again. Especially if the amp isn't even fully functional.

I might to so far as to send it back to Mesa for Mike B. to give it an overhaul. It'd be worth doing.

 

[CRobbins]

Here's a good photo of a pristine example to use as a reference. Anything that is different is suspect.

Note that this example doesn't have an EQ. That's OK. It just makes it easier to use as a reference for everything other than the EQ.

Thanks for the picture. I am going get this amp restored. I wonder if they were trying to get this amp to be like a MK I? I put some new tubes in it and it sounds good, but none of the lead gain, or the foot switch work, both disconnected. It's clean, and loud. I dunno....

 

[woodbutcher65]

Who knows? Take this as gospel: The number of people who attempt to modify amps is much larger than the number of people who are competent to mod amps and have them come out well.

 

[b00g13mk2B]

Agree that sending it to MESA for refurb is a good idea. The plate resistors have been replaced, which may indicate past problem with shorted tubes or some of the mods. Not a big deal, that can happen. The added small PCBA could be something with the effects loop or channel switching? Solder joints between an axial lead component and a wire, just hanging, are not factory.

 

[TiPiMods]

Man, that really looks sad. Real hack job...looks like a lot of caps and other components are missing. Get some tech with good reputation or send it back to Mesa to restore it. Mk IIBs are great amps, I love my SRGX for it's bold and punchy sound, beautiful & full sounding reverb. Big cleans and a great platform for pedals.hope you got it cheep, because this will be quite some work & money to restore. but it will be worth the effort

 

[CRobbins]

I just shipped the amp back to Boogie yesterday. Lets see what develops.

 

[CRobbins]

My amp is at Mesa/Boogie being refurbished. I am also getting the fx loop mod done while its there...

 

[CRobbins]

I got my amp back from Mesa/Boogie. Everything works. Now the fun part begins. Making this thing sing. 8)

 

[Markedman]

Envious, Jealous and very glad you sent the amp back. There's absolutely 0% chance that it sounds anything but great.