I put the 1k ohm resistors back into R30 & R31 and tested the amp - same results. I then took out the 500ohm resistors from R60 & R60A and replaced them with fresh 220 ohm 1/8w resistors. Again I have the same results where with the IRF3205 in place the gate waveform crumbles and the fet overheats.
I then realized that for this to work right, I need a fet in each bank of the PS. With one fet in each bank, the amp powers and holds power without strain and the gate waveform looks good.
So, was the solution to lower the pre-driver 'base' resistors from 500 down to 220 ohms?
I would replace the resistors with a jumper wire. I don't know why they did this. It may be to protect the driver board. If so, they should have had the pulldown resistors connected directly to the base of the drivers. Having the base resistors between the pulldown resistors and the base slows the drive circuit down.
I'm guessing that the little glitch on the falling side of the waveform is less significant and lower on the waveform than before. Is that what you're seeing?
I'm guessing that the little glitch on the falling side of the waveform is less significant and lower on the waveform than before. Is that what you're seeing?
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