Rockford Fosgate PUNCH 401S repairing

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Yes you can replace with IRF3205 but you must change the gate resitors to 47 ohm. Be sure to also replace the 2 pnp and 2 npn drivers next to the pwm (TL494C) marked 1A and 2A.

Before powering the amp check for shorted output fets and if any are found clip them out of the circuit before powering the amp.

Either someone accidentally reversed the polarity, or an output(s) shorted and took out the power supply.
 
I dont have a schematic so I am not sure of board location. If you could post a close up pic of the board I could circle them for you.

There are 4 driver transistors right near the pwm chip that are grouped together 2 npn's and 2 pnp's they are marked 1A or 1AM and 2A or close.

They are all right by each other.
 
So after looking at Perry's link yes you are correct.

Replace Q1, Q2, Q4, Q5 These are the drivers that need to be replaced.

Q1 and Q2 are the MMBT3906L marked 2A

Q4 and Q5 are the MMBT3904 LT1 marked 1A or 1AM

If you need anything else dont hesitate to ask.
 
Thanks for the info, Seankane, and Perry, too, by the link of the scheme.
This morning I went to the store to buy IRF3205, but had just three, mmmhhm ... I have to wait until next week ..
When I arrive and have everything installed, I will tell you if it works or not working.
 
Yes, I checked, and well, anyway, I have several reserve units, in my closet, IRF540 and the IRF9540.
The pieces were actually burned, were:
The four power MOSFET,
The three partners electrolytic capacitors, C20, C22, C24 (all, it was rare, but well marked, when checked, though, to be swollen and leaky)
I checked you said transistors (Q1, Q2, Q4, and Q5) and must leak or something, because each one gives me a different value ...
What do you think, can there be, something else wrong?
 
I think your on the right track, lets get the power supply up and running first.

Replace the power supply fets, gate drives, and the 4 drivers. Maybe you should consider replacing the power supply caps as well.

Once the power supply is up and running we can move to the output section.
 
Yes, thanks, hope to go on the right track,
I have to wait until next week to receive, one IRF3205 to try ...
The other pieces, and I have all welded, including electrolytic capacitors, which had them (I like to always have some spare parts)
Well, a greeting, and I'll tell you.
 
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