Hello,i got this amp for myself. In the audio section, only one mosfet (NTP35N15G ) is broken. Couldnt find a substitute.
Does somebody know a replacement. I want to change only the damaged fet,
could this work with other mosfets paralleled?
Does somebody know a replacement. I want to change only the damaged fet,
could this work with other mosfets paralleled?
If you have no other suggestions, the IRF3415 may work.
I wouldn't mix FETs in a parallel group. I'd suggest that all of the FETs in the parallel group are not only the same part number but also from the same production batch (matched date codes).
I wouldn't mix FETs in a parallel group. I'd suggest that all of the FETs in the parallel group are not only the same part number but also from the same production batch (matched date codes).
Hello, received the new parts,
but there is a small problem. Idle current about 4 Amps, output mosfets starts heating.
Amplitude is ok, checked the potis, maybe possible to adjust the dead time, but nothing happen.
Any suggestions?
but there is a small problem. Idle current about 4 Amps, output mosfets starts heating.
Amplitude is ok, checked the potis, maybe possible to adjust the dead time, but nothing happen.
Any suggestions?
What does the drive signal look like at the gates of the FETs?
JL, in the 500/1 and likely in this amp, used a parallel resistor and diode and a capacitor to generate deadtime. It's rare that there is a problem there. I'd expect the problem to be in the drive circuit nearer the outputs.
JL, in the 500/1 and likely in this amp, used a parallel resistor and diode and a capacitor to generate deadtime. It's rare that there is a problem there. I'd expect the problem to be in the drive circuit nearer the outputs.
I checked the resistor close to the fets, without fets inside. They are all in tolerance. Signal isn't good.
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Recheck the waveforms with the black probe on the source leg for the FET gate being checked.
The v/div isn't shown on both images. Did the scope change ranges between tests?
The v/div isn't shown on both images. Did the scope change ranges between tests?
It's possibly triggering but with the signal, it's being modulated so it looks blurred.
There is a 555 timer and LM319 together. Find the terminal of the LM319 that has the signal from the output of the 555. The other input of that 1/2 of the 319 is driven by an op-amp. Which op-amp is it? It should be in that general area.
There is a 555 timer and LM319 together. Find the terminal of the LM319 that has the signal from the output of the 555. The other input of that 1/2 of the 319 is driven by an op-amp. Which op-amp is it? It should be in that general area.
I think the 555 signal comes from pin 6 and drives pin 5 of the 319. Pin 11 of the 319 is supply voltage.
If the 555 drive pin 5 of the 319, audio drives pin 4.
If the 555 drive pin 5 of the 319, audio drives pin 4.
Yes, you are right. On the first op amp 505 i have the sine wave, and at pin 4 lm319 there is also a signal.
Is it quit normal, that the amp is pulling 1,9Amps, without outputs?
The signal for Pin 4 is comming from pin 1 of an 2068
Is it quit normal, that the amp is pulling 1,9Amps, without outputs?
The signal for Pin 4 is comming from pin 1 of an 2068
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I wouldn't expect it to be drawing that much current. Monitor the temperature of all of the PS FETs.
For the op-amp driving the 319, solder a bridge between terminals 1 and 2.
Does that give you a good drive to the outputs?
For the op-amp driving the 319, solder a bridge between terminals 1 and 2.
Does that give you a good drive to the outputs?
Is this at the gate legs of the FETs with the outputs installed but the rectifier out of the circuit?
It would be more definitive with the FETs in the circuit (no rectifier) so that the drive circuit had a load.
I don't know if it works with this amp but the 500/1 would give a drive circuit if you pulsed remote for a second. The 500 gives about 15 seconds of driver supply voltage after remote is removed. The main supply has a delay.
I don't know if it works with this amp but the 500/1 would give a drive circuit if you pulsed remote for a second. The 500 gives about 15 seconds of driver supply voltage after remote is removed. The main supply has a delay.
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