Itchy's mps2500

bogart · Post by **bogart** » Tue Feb 16, 2010 12:51 pm

ok...this is one of the two amps I picked up in seattle for itchy....knew they didn't work when they were purchased....

So far I've gotten it apart and started the cleaning and polishing process...all the while taking note of what has gone out on the amp...I am getting pretty familiar with the ms power supply so I do believe that I've got most of it sorted out...

Of course I will have to swap out the obviously bad components and power it via dump resistors to really see what it is doing and if I still have more sorting to do...

but so far the right side power supply fets are toast...one cap was bad and the 5401 diodes in the p/s rails tested poorly as I somewhat expected with the hammered fets...of course, if you do one side you have to do both...but that is neither here nor there at this point....r271 and its corresponding rectifiers in the circuit need to be swapped out and the small caps off the right channels output rails all need to go as one blew up when the fet failed...the fuse blew...the one that bridges the output rail to the p/s cap and that cap was damaged...blew a leg off it....all in all the p/s issues are cake as no rails were damaged and the fused did what they were supposed to do...save the bjt's and the core of the audiopath....

of course this amp was filthy...sat open for years in a garage and had a few dead spiders and some dust bunnies in it....in the pics you can tell where and what I've done thru the stages I clean all these amps through and then I will polish it all up...I think the board will be lovely as you can see it is cleaning up nicely....

The pics here are how she sat the day I got it back to town.....in the next post I will load the way she sits now and the damage I've found.....

bogart · Post by **bogart** » Tue Feb 16, 2010 1:02 pm

so here is how she sat as of 4am this morning....been here late and can't sleep so.......will have to post the rest in the next

bogart · Post by **bogart** » Tue Feb 16, 2010 1:05 pm

next few photos...they are in order so some you may see more done and they will regress from there

Post by **kg1961** » Tue Feb 16, 2010 1:05 pm

crap your fast looking nice!

Post by **Eric D** » Tue Feb 16, 2010 3:38 pm

I would pull the RCA cables off the amp while you are at it. Chances are they are ready to break off on their own.

Is that your soldering iron cleaner next to the amp? If so, where did you get that holder for it?

bogart · Post by **bogart** » Tue Feb 16, 2010 3:42 pm

I got that at norvak electronics locally...10 bucks

I will most likely replace the rca with some blue ixos braided rca..

Misfire · Post by **Misfire** » Tue Feb 16, 2010 4:06 pm

Nice work Bogart. She is looking 100% better all ready. Though I bet your eyes are blood shot from staring at that board while scrubbing it clean all night!

Post by **Eric D** » Tue Feb 16, 2010 4:31 pm

It is pretty extreme, but I have washed boards in the sink before. A little dish soap and a tooth brush, then thoroughly rise and let dry completely.

Post by **mhyde71** » Tue Feb 16, 2010 4:50 pm

^^^ no way-
bet'cha thats fine if done properly....dont go wiring it up thinking that the heat from the fets or devices will help dry it off though

oldskoolmseriesfan · Post by **oldskoolmseriesfan** » Wed Feb 17, 2010 2:10 am

Very nice work Bogart, you are a true tekkie. I wish I had your talent for fixing these killer amps....cheers

KUB3 · Post by **KUB3** » Wed Feb 17, 2010 2:53 am

Have you guys noticed that some MS boards are assembled much more neatly than others?

On many boards the FET's seem to have been soldered in rather messily with large solder lumps visible on every FET leg. Whilst others feature totally immaculate FET installation with hardly any solder at all. My best two amps look perfect (almost as if made by robots or perfect workers) but many look rather messy indeed! I guess it depends who made each one.

bogart · Post by **bogart** » Wed Feb 17, 2010 9:52 pm

here are a few pics of the completely cleaned amp next to my 2125 board...can you tell the difference....I think my 2125 may well soon be a 2500....

Post by **mhyde71** » Wed Feb 17, 2010 10:10 pm

wow freeekin fantastico mang!

good show!

m

bogart · Post by **bogart** » Wed Feb 17, 2010 10:18 pm

Danke Meinen freund!!!! Would you believe that that is the 2125 I got from you...all the green stuff came up....looks pretty good. I would like to take these two boards and make mine an mps2500 too...stuff em in a sink and she'd be one big sexy 1/4ohm bitch...

Post by **mhyde71** » Wed Feb 17, 2010 10:41 pm

wow!
great werk mang!
no! In fact, it is hard to believe

Misfire · Post by **Misfire** » Thu Feb 18, 2010 12:11 am

dam, they both sure cleaned up well, how is your wrists doing???

Itchy's mps2500

Itchy's mps2500

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