MPS power supply transformer repair

oldschoolfan · Post by **oldschoolfan** » Wed Feb 10, 2010 5:46 pm

I need advice. I am trying to fix this here MPS 2500 with a shorted transformer. I left the photo large so you can see what's up. The magnet that shorted is not coated like the other two. I am assuming a little friction over time wore through the coating on the winding. Poof.

My question to those that know, what can I coat this thing with to protect it and prevent this from happening again?

Post by **Eric D** » Thu Feb 11, 2010 8:06 am

Ask PG for a new core, they may have some still. I bought two not too long ago.

But you would still have to then rewind it. I have a MPS2500 I use for parts. If you can't solve this yourself, I may be willing to sell you one of the transformers from my board.

Post by **mhyde71** » Thu Feb 11, 2010 8:47 am

in lieu of above mentioned...
perhaps a lacquer or something similar, maybe varnish or something...

otherwise an epoxy of some sort- from powder coaters stand point-
something like:
http://www.columbiacoatings.com/Poly_Ru ... _s/258.htm

or perhaps
http://www.columbiacoatings.com/category_s/114.htm

http://www.columbiacoatings.com/category_s/37.htm

oldschoolfan · Post by **oldschoolfan** » Thu Feb 11, 2010 10:21 am

Thanks Eric and Matt. I have sent an email to each to see what they can do. I'll report in when I have some information.

oldschoolfan · Post by **oldschoolfan** » Thu Feb 11, 2010 3:43 pm

Columbia emailed me back super quick. They do not offer anything with dielectric designed capabilities. Thanks anyway Matt, it looks like they have a great product line.

Post by **mhyde71** » Thu Feb 11, 2010 3:53 pm

in addition to eric... i also do have a 275 torrid...BUT it is wound, but curious to know if the magnet would be viable...maybe eric can chime in....
I am inclined to think that the magnet may in fact be different diameter, but if not, i have one and it is already out from board and ready to go....OR maybe they are all same magnet, just wound/configured differently...? BUT i really dont know for sure.... my 2250 is out in car encased and wouldn't be able to do a good/great comparison

might keep eric from pulling his out and ridding of his that he might be trying to save for rainy day...

do you have a 275/250/2240 there to check the differences in diameter if any??

Post by **Eric D** » Thu Feb 11, 2010 5:04 pm

Here is a photo of a MS275 next to a MPS2500. They look the same to me.

The gray ring is from a MS2250TA transformer.

Also, these are not magnets, they are just iron cores made of powdered iron pressed together under intense heat and pressure.

Post by **mhyde71** » Thu Feb 11, 2010 5:08 pm

okay cool... so if thats the case...
I have a 275 torrid available

lmk if you would like

matt

Post by **Eric D** » Thu Feb 11, 2010 5:14 pm

What would actually be ideal is if someone had a burned board which was of no use to anyone else. When these amps burn up, most people throw them away, not realizing how useful the parts are which have survived.

Post by **mhyde71** » Thu Feb 11, 2010 5:20 pm

^^^ here here

i would have to agree, i mean i would just assume to hold on to the transformer...BUT i dont see any short term use for it, and if someone could use thats great!, but
It is all config'd to be used in 275, and would be ideal to see it go for it's intended use, but hey- it's doing nothing right now in my parts box.

so whatever happens happens

Post by **ttocs** » Fri Feb 12, 2010 6:59 am

I do not think those toriods look alike at all other then the red wire wrapped around the magnet. The one on the left has alot more wraps on it and doesn't expose any of the magnet unlike the one on the right.

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Post by **mhyde71** » Fri Feb 12, 2010 7:22 am

think/thought what they're/we're referring/speaking about to is just the "magnet", which we have since learned is actually

just iron cores made of powdered iron pressed together under intense heat and pressure

-

NOT the actual winding(s) as a complete transformer, BUT just the "magnet"/iron core is the same size/diameter etc...

did you like that?
think/thought what they're/we're referring/speaking about

Post by **mhyde71** » Fri Feb 12, 2010 7:26 am

my guess is, that he would unwrap/unwind the faulty transformer, and re-wind onto the new (non-faulty) ms275 iron core, and be back in business

Post by **Eric D** » Fri Feb 12, 2010 9:38 am

I thought we were talking about the core of the transformer, not the windings on it.

marko · Post by **marko** » Fri Feb 12, 2010 10:31 am

would be a lot easier just to swap out the bad transformer, i wouldn't like the job of rewinding that!

shame joergs board is an ms2125 as that would of been ideal..

oldschoolfan · Post by **oldschoolfan** » Fri Feb 12, 2010 11:19 am

Ok, here is an update. I have a picture of the core placed on my MS2250. These cores are the same size. Eric's picture shows a 2250 core on an MPS 2500 board. That 2500 board seems to have the same size transformer as a 2125. Hmmmm. It looks like they just put together whatever they felt like some times. My board # is 213921 revision E. A 2125 serial number, even more confusing. Anywho, it is what it is. I have a core the size of a 2250 so I guess that is what I need. Anyone willing to sell one, unwound preferably as they were not wound the same, that would be great!

Post by **Eric D** » Fri Feb 12, 2010 11:45 am

I know this will sound like a really dumb question, but are you sure you have a MPS2500, and not a MS2125? I have actually found MS2125 boards in MPS2500 heatsinks before.

Post by **Eric D** » Fri Feb 12, 2010 11:47 am

Also, if it were me, I would just wrap the core with one layer of black electrical tape. Something nice, like Scotch 33+. It would actually be better than the ceramic coated cores, as the wires would stay put. On the ceramic coated ones, the wires slide around way too easily.

marko · Post by **marko** » Fri Feb 12, 2010 11:49 am

what interests me is the dual windings on the input nulling toroid, usually single winding on ms2125 and mps2500..

oldschoolfan · Post by **oldschoolfan** » Fri Feb 12, 2010 11:54 am

Eric, so not a dumb question. No, I am not sure it is not a 2125. I don't know what components to look at to see the difference. The one I have that I think is a 2500 is the only one I have seen in person. I figured that the larger transformers could be an obvious visual but now it seems per your 2500 that maybe it is just a rarity. Any major or obvious things to look for, fet numbers or the like?

Sure I guess tape would work but... I don't know if I could just live with function. I do like form as well. However I am sure you can see by the picture that this one has seen some heat and will never win a beauty contest.

marko · Post by **marko** » Fri Feb 12, 2010 11:57 am

there should be some numbers on one of the legs of the transformers, this will tell if it's a 2125 or 2500..

EDIT- think i may be wrong, only the smaller 275's etc may have identification tags on transformers!

oldschoolfan · Post by **oldschoolfan** » Fri Feb 12, 2010 12:00 pm

This amp does not have those on either transformer.

marko · Post by **marko** » Fri Feb 12, 2010 12:03 pm

oldschoolfan wrote:This amp does not have those on either transformer.

like this, i knew i wasn't imagining things!!

oldschoolfan · Post by **oldschoolfan** » Fri Feb 12, 2010 12:06 pm

No, definitely not imagining. My other amps have them but not this mystery machine.

oldschoolfan · Post by **oldschoolfan** » Fri Feb 12, 2010 12:10 pm

It appears to be the same as the 2125 in that the transformers use the same board locations and winding configuration, just not the small diameter core. I don't know what to think. Marko I like your observation on the input nulling torroid. It looks like the double winding was only used on the 2250, at least from the pictures I have seen and the one that I have.