Hi,
Does anyone know the correct value for R29, R33, R27, R28, R32, and R34. The mosfets are IRFZ44N, I think the resistors in place now are incorrect, since they get warm (or have wrong wattage?). Other than that the amp runs fine. Thanks for your help.
Does anyone know the correct value for R29, R33, R27, R28, R32, and R34. The mosfets are IRFZ44N, I think the resistors in place now are incorrect, since they get warm (or have wrong wattage?). Other than that the amp runs fine. Thanks for your help.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
If the numbers on the board are the production date, it would appear that the resistors have been OK for more than 10 years. It's possible that a different resistor would have been a better choice but if the amp is working, it may be better to leave the resistors as they are.
R27,R29, R28 are all 91 ohms.R34-27ohms,problem is R33 there is no color coding.
but i think R33 is still good cause its not burn-out.
but i think R33 is still good cause its not burn-out.
Thanks for the replies. When I got the amp, it was broken. The PS mosfets and their resistors were burnt. I measured the gate resistors, but they were arond 1k, and some other resistors near them read open. I had another amp with IRFZ44N, so I used that as an example. The resistors you see now are not the original configuration. The resistor R33 with no marking is 27 ohms. I would like to know the original value for these resistors. As you can see some of them are already turning brown. They start out warm and gradually get quite hot, so you can't touch them. The mosfets run cool.
Do the over-heating resistors connect from the emitters of the gate driver transistors to ground?
I'm away from the amp, so I can't say that for sure. The blue ones you see are over-heating. Two of them connect from the emitter of the drive transistors to the gate of the mosfets. I'm not so sure about the other two. Is it normal for them to run warm? Do their value affect how hot they get? Maybe I should just use 1/2 or 1W resistors?
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