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ms275 ko...

Posted: Fri Dec 21, 2012 7:17 am
by stefano7689
hello my name is Stefano, I'm from Genoa, Italy.
I inherited a phenix gold ms275 white version, namely rev-h.
The amplifier was wonderful on medium to high frequencies.
One day, while driving, following an off something must have happened, a short circuit I suppose, and he stopped playing.
open the amplifier I found this scene.


hello my name is Stefano, I'm from Genoa, Italy.
I inherited a phenix gold ms275 white version, namely rev-h.
The amplifier was wonderful on medium to high frequencies.
One day, while driving, following an off something must have happened, a short circuit I suppose, and he stopped playing.
open the amplifier I found this scene.

http://imageshack.us/photo/my-images/21 ... 25426.jpg/
http://imageshack.us/photo/my-images/90 ... 25433.jpg/
http://imageshack.us/photo/my-images/25 ... 25958.jpg/

three of mosfet irfp044 exploded!
now I would absolutely fix it, I brought a friend who fixes amps, and asked me to find the wiring diagram.
you can give me a hand?
where can be the problem in your opinion?
regards Stefano

Re: ms275 ko...

Posted: Sat Dec 22, 2012 2:34 am
by zeropoint0.5
try to upload pics again, you can only see red crosses........

Re: ms275 ko...

Posted: Sat Dec 22, 2012 3:29 pm
by stefano7689
Here are the photos! Does anyone know what is the switch on the motherboard?

Re: ms275 ko...

Posted: Sat Dec 22, 2012 3:47 pm
by zeropoint0.5
the switch lowers the rail voltage so you could play on lower impedances if i'm not mistaking....

It seems you have here blown up you're powersupply....... but it will normally be possible to repair it......

Re: ms275 ko...

Posted: Sat Dec 22, 2012 10:47 pm
by trickyricky
Might as well replace the caps. Don't forget the gate resistors for those fets, they might be off a bit or damaged. Also check the outputs before powering up. Its repairable, but the components may not be cheap, but the amp is worth it.......just look at that sexy board.

Re: ms275 ko...

Posted: Mon Dec 24, 2012 2:01 pm
by valeks1
The reverse polarity diode is blown. This only happens when the B+ and B- wires are connected to the amplifier backwards. This can also damage your PS MOSFET’s and this is why they blowup.

Re: ms275 ko...

Posted: Sat Jan 05, 2013 11:27 am
by stefano7689
What do you recommend I do? replace the diode and the mosfet? and that's it?
the circuit diagram does not have any?

I have not reversed the polarity! the amp sounded! it may be a short circuit?