# Rockford Fosgate Amp repair



## i.love.zs

I got an old RF amp from a friend for free, a Punch 200S. It had stopped working for him a while ago, and he didn't know why. I pulled the cover off the board, and found this:



I know it is a fried BUZ100 transistor, and I have the soldering skills to repair that, but is it possible that something else got cooked as well? Any tips or things to avoid while fixing this?


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## i.love.zs

bump, anyone?


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## ChrisB

Working with MESHA strips makes me want to kick a puppy. Those tiny surface mount devices are no picnic either.


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## envisionelec

ChrisB said:


> Working with MESHA strips makes me want to kick a puppy. Those tiny surface mount devices are no picnic either.


Someone's already been in there. MESHA is do-able with the right equipment - but it's not cheap and still a huge puppy-kicking moment. 

One blown FET means you *should* replace the entire phase. If the short is between all three legs, you're likely looking at replacing the MPSA06/A56 totem driver. My RF amp repair memory is fuzzy - I haven't worked on one since the BD1000 came out...what - ten years? I should stop - I'm becoming irrelevant.


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## ATOMICTECH62

In my experience with these amps I always have to replace the drivers for the mosfets.There usually close to the 494 pwm ic.There marked with 1A and 2A.There are 2 each.Also you will need to replace the gate resistors and sometimes the tl494 ic.Do you have a scope?


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## ChrisB

envisionelec said:


> Someone's already been in there. MESHA is do-able with the right equipment - but it's not cheap and still a huge puppy-kicking moment.
> 
> One blown FET means you *should* replace the entire phase. If the short is between all three legs, you're likely looking at replacing the MPSA06/A56 totem driver. My RF amp repair memory is fuzzy - I haven't worked on one since the BD1000 came out...what - ten years? I should stop - I'm becoming irrelevant.


I picked up a T10001 bd stuck in protect thinking it would be an easy fix (silly me). I think it took me all of 10 minutes go give up on it.


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## Blancolex300

ChrisB said:


> I picked up a T10001 bd stuck in protect thinking it would be an easy fix (silly me). I think it took me all of 10 minutes go give up on it.


Mine does the same thing. Now it's a paperweight.


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## kyheng

I got a Lightning Audio Strike monoblock discharge 12V DC on speaker output, thought was a fried opamp, but it seems like it is a more serious problem.... Still in repair shop after 1 month. 

Basically, it is easy to know when there's a fried component and people may think "it is just a fried component, I change it and I'll good to go". But this is not the case, especially dealing with more complicated circuit design. Knowing the actual cause that fried the particular component will be important.


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