MS2250 Repair (Burned Board)

Post by **Eric D** » Mon Mar 19, 2007 12:25 pm

Follow Dr. Fosgate on yet another adventure as he attempts to repair the impossible, and extremely unprofitable…

http://www.soundbuggy.com/forum/viewtop ... 0984#50984

Post by **Eric D** » Wed Mar 21, 2007 11:22 am

Capital_M · Post by **Capital_M** » Wed Mar 21, 2007 11:24 am

thats fuckin cool

twisted · Post by **twisted** » Wed Mar 21, 2007 11:58 am

Capital_M wrote:thats fuckin cool

no shit thats cool. i wish i had the aptitude to repair these things!!!!!!

1moreamp · Post by **1moreamp** » Wed Mar 21, 2007 12:50 pm

DAMN thats alot of work to do that. thats truly a labor of love!

dgoodhue · Post by **dgoodhue** » Wed Mar 21, 2007 1:20 pm

Is that FR3 or FR4 2 sided copper?

Post by **Eric D** » Wed Mar 21, 2007 1:57 pm

It is RadioShack copper...

HoseHead · Post by **HoseHead** » Wed Mar 21, 2007 2:46 pm

That's talent and passion. An elite craftsman without doubt. Very nice.

Now, what caused that failure?
Was there a tin foil fuse in there or what?
It pulled some amount of current to punch a hole through the board.

HH

Post by **Eric D** » Wed Mar 21, 2007 3:04 pm

The fluid leaked out of the capacitor and caused an internal short. I highly doubt this was a case of abuse at all. All of these old M and MS, plus some ZX amps seem to die this way in time.

Post by **Eric D** » Wed Mar 21, 2007 3:05 pm

I used my scanner, and the board from my MPS2500 to figure out where everything should go. I created a black image of the areas where traces should remain. Then using the laserprinter, iron, water, PCB prototyping method I generated the graphics on the PCB, and ground away the extra by hand. I probably could have taken my time and then chemically etched the board, but no matter what I do, this will not look all that pretty, so I did not think I should waste the effort.

Post by **bdubs767** » Wed Mar 21, 2007 3:51 pm

wow that is simple impressive DOC

Post by **Eric D** » Wed Mar 21, 2007 3:59 pm

I think this new method will be a lot stronger and more effective than my previous methods.

marko · Post by **marko** » Thu Mar 22, 2007 9:47 am

makes me want to have a go at fixing THAT m50 board!! i need an m50 transformer though

Post by **Francious70** » Thu Mar 22, 2007 12:04 pm

Wow, that's amazing.

BTW, what is the red string hanging off the board in that first pic??

marko · Post by **marko** » Thu Mar 22, 2007 12:15 pm

Francious70 wrote:Wow, that's amazing.

BTW, what is the red string hanging off the board in that first pic??

think that's the wire that runs to the fan temperature sensing circuit....

Post by **Eric D** » Fri Mar 23, 2007 3:29 am

I have no clue what the red wires are. They were on my MPS2500 also, yet closer to the endplate the amp has thermal sensors. Maybe these amps had dual sensors, but I doubt it.

rolandk · Post by **rolandk** » Fri Mar 23, 2007 7:52 am

Nice job Eric! The red wires (and there shoud be a black wire w/ each red) go to the fan speed control PCB that mounts on that plexi block between the fuses.

vin78 · Post by **vin78** » Fri Mar 23, 2007 9:11 am

Wow, this is amazing work!

Post by **VW337** » Fri Mar 23, 2007 9:26 am

You are a magician...............

The work you perform is just dumbfounding.

dragonplayboy · Post by **dragonplayboy** » Fri Mar 23, 2007 10:33 am

That would be funny if you hooked it up and it blew all to hell again, like immediately.

Post by **VW337** » Fri Mar 23, 2007 10:37 am

dragonplayboy wrote:That would be funny if you hooked it up and it blew all to hell again, like immediately.

Post by **Eric D** » Fri Mar 23, 2007 11:17 am

The only time these amps burn up like this is when their capacitors leak, or if from serious abuse a transistor catches fire, which is highly unlikely.

I don’t foresee this amp failing in this way again for a very long time (until the new caps fail, which should be far longer than the originals).

Thanks for all the comments. Does anyone by any chance know where I can get blank PCB which is gold plated copper? If I had that, and did some sort of etching process, I could make near perfect patches for my amp repairs.

Also, Roland, do you guys by any chance have blank PCBs which I could get scanned or, buy?

rolandk · Post by **rolandk** » Mon Mar 26, 2007 7:54 am

Eric D wrote: Also, Roland, do you guys by any chance have blank PCBs which I could get scanned or, buy?

Do you mean an MS2250 PCB with all the traces that hasn't been stuffed with components, or just a PCB will no traces at all?

Post by **Eric D** » Mon Apr 23, 2007 4:36 pm

Update: The amp works!

I still need to clean the board and tidy up some things with it, but I hooked it up and played some music for a bit.

Post by **stipud** » Mon Apr 23, 2007 5:43 pm

That repair is so awesome I would display it under plexiglass.

Well done.