Wanted Mk4 amplifier motherboard

[[email protected]]

Hello all,
My Mk4 combo motherboard has fried according to the repair engineer who checked it
Does anyone have a motherboard for sale?
I could then hopefully get my baby working again
Thanks

Eddy

 

[[email protected]]

Hmm, no answers

Has anyone ever replaced the motherboard? Seems a real shame to have to scrap this combo

Eddy

 

[Wolfgar926]

first, how did the main board get fried>? whats the cause? have to know that. or you put in another. and may fry it also!
as for buying a main board. the only place to get one is mesa boogie.com and it wont be cheap. you wont find a used one. did you have some power tubes go out and fry the board? what happened?

 

[[email protected]]

Mesa Boogie was the first place I contacted, they do not have any replacement boards

The guy who looked at it is a Mesa Boogie approved engineer, he said there was arching on the board so not repairable

This started of just being a humming noise which would start after the amp was on for a while

 

[MesaMad1378]

Hi there,
I’ll buy it off you? $200 as it is no good

 

[[email protected]]

Ok, postage will be about £1000 to you though given the weight of it!

 

[Markedman]

https://reverb.com/item/42051650-mark-iv-style-diy-complete-pcb?utm_source=rev-ios-app&utm_medium=ios-share&utm_campaign=listing&utm_content=42051650

Is this what you’re looking for?

 

[[email protected]]

Wow, yes, let me ask my tech guy if that is what is required

Thanks a lot

Eddy

 

[Wolfgar926]

what did you find out? will the ebay board fix it? sounds like when the amp started humming a power tube was going out. and ended up ruining the board. didnt shut it down fast enough... when you hear any hum. shut it down as fast as possible. sometimes it will ruin things. most of the time not the board. unless left humming for a while. til the tube burns clear out. getting the board super hot and shorting out ...

 

[[email protected]]

I did not buy the board, my tech guy said it was very expensive and it would have cost a lot for him to transfer everything over to the new board.

So looks like I will have to just sell the amp as is, maybe someone has a Mk 4 head they want to turn into a combo

 

[user.39921]

Where are you located?

 

[[email protected]]

I'm in London UK Dan

 

[msi]

Just how damaged is the amplifier? The parts do not need to be mounted on the board. Also if the traces are damaged a wire could be ran in place of the damaged trace. You might have your tech provide you pictures as someone on here may know a tech that could do that kind of repair.

 

[domglop78]

hello
i have one (mother PCB , power pcb, footswitch pcb and GE pcb, all for Mark 4

if you are interessed send me an email

dom

[email protected]

 

[[email protected]]

I sold the amp last week, the chap who bought it might be interested in the motherboard, he is on here as well I will email him

Thanks all

Eddy

 

[woodbutcher65]

Arcing is totally repairable but it requires a technician who's a cut above average.

You use your Dremel to grind out the arced out area. Get it ALL out. You then rebuild it with fiberglas and wire in the traces by hand using solid core wire of appropriate gauges.

 

[user.39921]

https://youtube.com/playlist?list=PLhH344YIgC0hqutXXi8T3RN2LUBM9_Wwk

Here is what happened w/ that Mark IV. Documented 80% of the process in a picstory vid.
Already recorded 1 EP and reamped another full album for a client.

Read the video descriptions for more info and what I discovered about this amp. It's a really rare version that is more valuable kept original. Replacement PCBs will be very different from this as they copy the available schematics for A or B. This one turned out to be an early transitional B model.

Cheers!

 

[Eevil]

https://youtube.com/playlist?list=PLhH344YIgC0hqutXXi8T3RN2LUBM9_Wwk

Here is what happened w/ that Mark IV. Documented 80% of the process in a picstory vid.
Already recorded 1 EP and reamped another full album for a client.

Read the video descriptions for more info and what I discovered about this amp. It's a really rare version that is more valuable kept original. Replacement PCBs will be very different from this as they copy the available schematics for A or B. This one turned out to be an early transitional B model.

Cheers!

Happy to see such handicrafts skills (and perseverance :mrgreen and tremendous amp coming back to life.

 

[woodbutcher65]

Strictly for informational purposes, there's a vendor on ebay selling Mark IV PC board kits to homebrew your own Mark IV clone.

 

[user.39921]

Don't buy unconfirmed PCBs, please!
Fortunately, this particular Mark IV B was saved from similar eBay PCB "repair".
It's a transitional model between "A" and "B" revisions - undocumented schematic, rare example. (Well, I documented it while repairing, but won't share it for obvious reasons) So in this case it won't work properly straight away with just swapping any of the "A" or "B" clone PCBs.
It would've ruined a perfectly good amp that just needs some love and attention.

I wouldn't trust such a random PCB even if it was a well documented build, with decent schematics (most Mesa schematics have mistakes in them).
There are files for making PCBs and most of those ridiculously priced "clones" are printed from them, but after tracing this transitional Mark IV a regular "B" - I can assure you those files are not the real deal.