Punch 500a2 distorted channel

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Yes but you need to remove all defective outputs (check gate to drain).

Check the gate resistors after removing the FETs to confirm that they're within tolerance.

Install them and measure the gate voltage. Make sure that both sides have ~5v DC on the gates. If the voltage is not the same from one side to the other, there may be a problem with the drive circuit.

When measuring the voltage on the gates, do so with ONLY remote and ground connected. Do NOT connect the B+.


I got it to turn on and played music through the good channel i only did this for a few seconds! It turns on, i stuck 3 buz10s inside for testing and it turns on!! Does this mean it's going to survive?? All i got to do is get the 3205s and gate resistors, right? And of course new output transistors. Btw can you please direct me to the correct gate resistors? Thanks, thanks!
 
The gate resistors are nothing special. 0805 size, 47 ohms.

I can't answer the question about the outputs without knowing 'precisely' which transistors failed.

Left channel failed I measured continuity on the driver transistors and I get 647 ohms from base, collector, emitter. And that's for both transistors but a couple gate resistors are reading 0.8 ohm.
 
How do you define 'better'?

I mean when I said 'which is better' which fet will be able to handle alot of stress in a switch mode power supply? Not that I'm going abuse the amplifier & run it below it's recommended load. I'm going to use it for daily driving (bridged to a single 4 ohm woofer) and I want make sure it will last along time. Also I ordered new outputs and gate resistors haven't got anything for the power supply because I'm still deciding on a "good" fet to use. Thanks
 
okay i've got new outputs by "Vishay" and 8 IRF3205s i got 4 more just in case something should happen, which i hope i make it right the first time. All i got to do is get the butane torch & 47 ohm gate resistors.

Oh and is 12 ohms 'normal' for the gate resistors on the outputs? When the bad fets were in the circuit they were reading 8 ohms now they read 11 or 12 ohms.
 

Perry, i noticed Q123 gets very hot it's located near the driver transistor on the left channel, the other on the right channel stays cool. I was going to just install the outputs in asap but the i noticed that Q123 is gets hot and i'm not sure if i should replace or what?? I have not received the parts yet but i'm using test FETs for meanwhile.
 
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