jol50 said:The best thing to do is make sure all the transistors are matched, because if one runs harder/hotter it will blow and take out the rest. That is also why the gate resistors are often replaced too, they throttle them and cost nothing to buy. If a transistor goes bad it can short back into the resistor and damage it or they could be out of spec anyway. If everything runs equally you will get the max out of all of them instead of one blowing and spoiling your fun. That is the best way to make the amp durable/powerful as it was intended to be. Actually adding power would be very complicated, require design and testing of many variables depending on the amp. The way things are today it would be much cheaper/faster to just buy a larger amp anyway unless you like blowing and fixing amps, but some people do.
now you just made me remember when I was buying replacement IRF3205's for an amp I was repairing, the store clerk handed me four harris 3205's (for about $4 each!!!) and I needed eight. she said I could get them for around $2 each and I could get another four from another store. I said I needed all to have the same batch codes for best reliability and she said a 3205 is a 3205 all is the same.
ended up not buying anything as I wouldn't take anything other than IR parts and didn't feel like arguing. 
sorry for the rant, just wanted to share an experience....
There are conflicting views on parts. I read a thread here where a well respected amp designer said using different chips in the output of a class D was fine and IIRC a PS as well. Others do not agree but most do in saying you should put new in class ab outputs. The issue seems that you can't really test a transistor so you don't know its condition. If you put all new of a quality brand in then that is best you can do. Parallel components are only as strong as the weakest link, so one weak transistor wrecks the whole deal. I will admit to putting used ones in a couple amps, and I sold said amps for $20 or < (described as such and tested under a good load) or used them myself. They required a transistor that was $4 each or more. It was that or into the landfill and I thought better to repair them and had the time. Any amp actually worth repairing I would not do that. Most of them are fairly cheap thankfully. Considering the labor is more costly than the parts I always use the best brands or originals for repairs, usually there is little difference in price per amp anyway.
I don't think anyone even sells these parts around here anymore, I get everything online.
I don't think anyone even sells these parts around here anymore, I get everything online.
Hey Perry. I just recently changed the parts that I needed to. Everything was working fine but the thing was that it doesn't start up like it used to. Its actually hard to explain.
It also makes a noise coming from the subs as if the ground is bad. But all my connections are good. When I look at the subs, they are moving in and out when the volume is at 0.
I opened my amp again only to find out that one of the cap was blown and this dark brown liquid was leaking from it. Its that cap that says 2200 80V.
Is this the problem? And if so, do you think you can find the part # for me? Its a black cap.
Thank you so much.
It also makes a noise coming from the subs as if the ground is bad. But all my connections are good. When I look at the subs, they are moving in and out when the volume is at 0.
I opened my amp again only to find out that one of the cap was blown and this dark brown liquid was leaking from it. Its that cap that says 2200 80V.
Is this the problem? And if so, do you think you can find the part # for me? Its a black cap.
Thank you so much.
The 2200@80v probably isn't the problem but it needs to be repaired. Did the cap overheat and leak 'after' you replaced the parts (it would have been hot) or was it something that was damaged when the amp failed?
Is R101 near the RCA jacks within tolerance (220 ohms ±5%)? Completely disconnect the amp from the power supply and signal source before measuring the resistance across it.
What were you using for a signal source?
I haven't been able to find a 2200@80v that will fit in that location. I've been using 1800uf@80v and haven't had a problem with them. The part I used was a P7363 from Digikey.
You need to clean 100% of the electrolyte (brown liquid) from the board. If it has flowed under other components, you need to remove those components to clean under them. The electrolyte is conductive and corrosive and must be removed. Use cotton swabs and acetone to clean the contaminated area. If you've never used acetone, read the warnings carefully and use it outdoors with plenty of ventilation.
Is R101 near the RCA jacks within tolerance (220 ohms ±5%)? Completely disconnect the amp from the power supply and signal source before measuring the resistance across it.
What were you using for a signal source?
I haven't been able to find a 2200@80v that will fit in that location. I've been using 1800uf@80v and haven't had a problem with them. The part I used was a P7363 from Digikey.
You need to clean 100% of the electrolyte (brown liquid) from the board. If it has flowed under other components, you need to remove those components to clean under them. The electrolyte is conductive and corrosive and must be removed. Use cotton swabs and acetone to clean the contaminated area. If you've never used acetone, read the warnings carefully and use it outdoors with plenty of ventilation.
http://search.digikey.com/scripts/DkSearch/dksus.dll?Detail?name=P7364-ND
This looks exactly like that part.
This looks exactly like that part.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
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