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Help with McIntosh MC425 repair
Help with McIntosh MC425 repair
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Old 25th June 2019, 07:41 AM   #1
mkafridi is offline mkafridi  Pakistan
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Default Help with McIntosh MC425 repair

Hi,

I have a MC425 with burnt power transistors... I need a service manual or the part number for the transistors.

A good picture will be very helpful...
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Old 25th June 2019, 07:46 AM   #2
Perry Babin is offline Perry Babin  United States
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All of the large (TO-220 and larger) are power transistors. I assume that you're referring to the power supply FETs.

You should be able to read some of the numbers off of some of the FETs.

The IRF3205 with 47 ohm gate resistors are common generic replacements. They may work in this amp if the drive circuit isn't too weak.
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Old 25th June 2019, 12:28 PM   #3
mkafridi is offline mkafridi  Pakistan
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Join Date: Dec 2012
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Quote:
Originally Posted by Perry Babin View Post
All of the large (TO-220 and larger) are power transistors. I assume that you're referring to the power supply FETs.

You should be able to read some of the numbers off of some of the FETs.

The IRF3205 with 47 ohm gate resistors are common generic replacements. They may work in this amp if the drive circuit isn't too weak.
Yes, I was referring to the small transistors in the power-supply!

I want to know the exact model, so if someone can get me the model no. that would be great!
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Old 25th June 2019, 04:30 PM   #4
Perry Babin is offline Perry Babin  United States
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For MANY amps, the answers to various questions are not available but an amp can generally be repaired with a little work. Did you try to clean the transistors with acetone and get some of the numbers off of them?
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Old 28th June 2019, 01:34 AM   #5
miniman82 is offline miniman82  United States
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I put IRFZ44N into my MC443, it’s still pounding to this day. Even if all the FETs are burnt beyond recognition, you should still be able to make an educated guess as to what will work well in the circuit. Look at some data sheets, something will spring out as a candidate.
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