Can this Amp be fixed?

 

New member
Username: Casper_

Post Number: 1
Registered: Jun-06
This is a kenwood KAC-629S and it just recently stopped working after years of use. It doesnt smell burnt the only only thing that seems to be wrong with it is one of the mosfet semiconductors broke in half. the name on the semiconductor is IRFIZ34G. you can buy them at this store. http://www.bluestar-online.com/IRFIZ34G_p/irfiz34g.htm My question is, is it really worth it to try and repair it or could there be other problems not just this semiconductor?

The amp and semiconductor.
http://i5.tinypic.com/156pov5.jpg
http://i6.tinypic.com/156ppi1.jpg
http://i6.tinypic.com/156ps8p.jpg
 

Gold Member
Username: Illuminator

USA

Post Number: 3212
Registered: Apr-05
http://digikey.com/ has better prices, even for the IRFIZ34G. The problem is this: those transistors are sensitive, and if one goes, they all go (yours is actually burnt up...), so you would probably have to replace that whole bank of transistors. Not too bad, considering.

Personally, I think it's worth the cost to repair it-especially if it's just those four (which I think it is).

After replacing the components, you should use a series connected current limiter in the power wire. A 1.5-2 ohm 25w-50w (watt) resistor will work for most amps. You can also use a variable output power supply that puts out 12v with adjustable amperage output. Mount the amp back in the heatsink (transistors clamped) before applying power. This will help protect the new transistors if there is another problem.
 

Gold Member
Username: Safe_cracker

Chicago, IL US

Post Number: 1254
Registered: Jan-06
I wouldn't limit the current it may affect the turn on function, just run an inline 5A( defeat any other fuses) fuse. Also be sure to check the power supply fets, they can be bad too. Oh one other thing, even if you have one bad output tranny you will need to change all of them to keep them matched. Be sure when you order they are all from the same batch.. Polo. :-)
 

New member
Username: Casper_

Post Number: 2
Registered: Jun-06
thank you very much
 

New member
Username: Casper_

Post Number: 3
Registered: Jun-06
thank you much
 

Gold Member
Username: Illuminator

USA

Post Number: 3213
Registered: Apr-05
Yeah, limiting the current definitely affects the turn on function, over about 1 amp and it should be fine, though.
 

Gold Member
Username: Safe_cracker

Chicago, IL US

Post Number: 1255
Registered: Jan-06
In all honesty (@ss kicker) it may be easier to replace that amp, it may have been good for years the quality of the amplifiers build lacks quality and you can do a lot better, IMHO.. Polo. :-)
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