I think the problem is the drive circuit is marginal go/no-go for this many 3205s.
Assuming that the 1k pulldown resistors are back to 1k ohms (on the main board), I'd try replacing the two 220 ohm pulldown resistors with 100 ohm resistors. They need to be rated for 1w if you use them long term but a 1/4 or 1/2w will tell you if they're going to make a difference.
Assuming that the 1k pulldown resistors are back to 1k ohms (on the main board), I'd try replacing the two 220 ohm pulldown resistors with 100 ohm resistors. They need to be rated for 1w if you use them long term but a 1/4 or 1/2w will tell you if they're going to make a difference.
However that is NOT the source of the current draw!
I put just 2 3205s back and there's no more overlap, but still high current pull! So now what? Maybe there's an issue with the rail caps? I think I'll pull the diodes and see what happens.
Diodes removed and current is staying at about 1.2 A. Much more reasonable. So issue is after the diodes...
I put just 2 3205s back and there's no more overlap, but still high current pull! So now what? Maybe there's an issue with the rail caps? I think I'll pull the diodes and see what happens.
Diodes removed and current is staying at about 1.2 A. Much more reasonable. So issue is after the diodes...
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Perry,
What about the IRF9640s?
Back to those resistors that I said were getting hot earlier. They are not 22k. They are 2.2k (red red red) and I tried replacing them with 22k and the amp started pulling 10+ amps and smoked the 2 PSU supply FETs.
Anyway, those resistors have nearly 120V across them. 120/2200=0.05 So they should only draw only 0.05A each. That's over 6 watts so it makes sense they get hot, but wouldn't be the cause of the current draw.
So next item: I noticed the current draw greatly increases as I increase the supply voltage. At 12V it's drawing 8Amps.
So would the output FETs cause that increased current draw from an increase of input voltage to the supply?
What about the IRF9640s?
Back to those resistors that I said were getting hot earlier. They are not 22k. They are 2.2k (red red red) and I tried replacing them with 22k and the amp started pulling 10+ amps and smoked the 2 PSU supply FETs.
Anyway, those resistors have nearly 120V across them. 120/2200=0.05 So they should only draw only 0.05A each. That's over 6 watts so it makes sense they get hot, but wouldn't be the cause of the current draw.
So next item: I noticed the current draw greatly increases as I increase the supply voltage. At 12V it's drawing 8Amps.
So would the output FETs cause that increased current draw from an increase of input voltage to the supply?
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The resistor isn't passing the current that's causing the amp to draw excessive current but it may have an effect on the overall circuit function.
The 640s are the only ones I replace.
If the rail voltage is changing with the 12v supply input voltage, that could explain the difference in current draw.
Is the rail voltage regulated?
Are the rails of equal magnitude above and below ground?
The 640s are the only ones I replace.
If the rail voltage is changing with the 12v supply input voltage, that could explain the difference in current draw.
Is the rail voltage regulated?
Are the rails of equal magnitude above and below ground?
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