I have tryed to cooling with cold spry the sg3525 when it have frequency instability, and after is good. I think are two different problem, strange square wave and freq. Instability...
The amp was designed for the IRF540, not the 540N. The N-version has been found to be incompatible in other amps that use the 540.
Ok, i will find 540 version.
For test, can i test square wave without l-channel mosfet?
Square wave?
Why take out all of the FETs?
I don't remember if I ever drove these hard with the FETs out of the circuit. It's generally OK with other amps but I can't tell you if it's OK with these. They are significantly different, compared to other amps.
Why take out all of the FETs?
I don't remember if I ever drove these hard with the FETs out of the circuit. It's generally OK with other amps but I can't tell you if it's OK with these. They are significantly different, compared to other amps.
I have tryed without L-CH mosfet, and the square wave on drain pin of power supply mosfet is the same...
Did you try lowering the 12v supply voltage as I suggested n post 13 to see if the PS waveform changes?
i have this situations
other thing, without remote, i have VBATT on drain pin of powersupply mosfet, it's normal?
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I don't see anything out of the ordinary. This is a regulated power supply and the pulse width appears to be changing as expected with a change in supply voltage. If you check the rail voltage with the varying 12v supply voltage, you're likely to see no change in the rail voltage.
The waveforms on the drains of regulated power supplies vary greatly and unless the regulation has reached its limits, the waveform won't look like those of an unregulated power supply.
The waveforms on the drains of regulated power supplies vary greatly and unless the regulation has reached its limits, the waveform won't look like those of an unregulated power supply.
so, for you can be ok this wave form? rail voltage is ok, +/-56V. +/-15V don't is perfect, is +/-17V
I think it's OK but when I work on an amp, I don't care what the drain looks like. It varies greatly for regulated power supplies. I look at the gate drive. That's what's important. The only time I'm concerned about the drain waveforms is if there is evidence that there may be excessive ringing (causing snubber resistors to overheat).
The ±17 isn't significant but the ±56 is. That's more than 100v across the rails for FETs that are rated for only 100v. I would expect something more like ±35.
What is the DC voltage on pins 1 and 2 of the PS driver board?
The ±17 isn't significant but the ±56 is. That's more than 100v across the rails for FETs that are rated for only 100v. I would expect something more like ±35.
What is the DC voltage on pins 1 and 2 of the PS driver board?
sorry, it's +/-53V, but is correct because it's signed on PCB board..
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That's not rail voltage. That's driver voltage. Measure the rail voltage on the output of the filter inductors.
Ah ok, it's +/-37V.
So, you mean the problem are the non-correct mosfet? I don't found irf540, only irf540z or 540p..
On tme stock don't are availables... but if P version is ok, i will find other distributor, thanks