That's better.
Now try it on the output FETs. Remember, you won't ground the scope to anything but the 12v PS (like it should normally be connected). For the probes, you will only touch the tips of the probes to the circuit.
Post photos of the drive waveforms.
Now try it on the output FETs. Remember, you won't ground the scope to anything but the 12v PS (like it should normally be connected). For the probes, you will only touch the tips of the probes to the circuit.
Post photos of the drive waveforms.
Did you have the 'negative' scope probe on the source leg for both waveforms? It looks like one was reversed.
Are you driving a signal into the amp?
Are you driving a signal into the amp?
I'm back working on this amp again. When I install the output fets I lose drive and have -28vdc on the speaker terminals. Without the fets i have drive and no dc.
On post 99, you posted an image with the FETs in the circuit. What happened between then and now?
The fets on one side blew. I found out the inductor on that side was shorted. With the inductor out the amp works fine. When I dropped in a replacement inductor it went back to not switching again. It looks like its trying to start switching when I apply signal but cant
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I was referring only to the replacement inductor.
Does the amp pull excessive current?
Do you see DC voltage building on the speaker output (after the relays engage)?
Does the amp pull excessive current?
Do you see DC voltage building on the speaker output (after the relays engage)?
I just noticed with either one of the inductors in the wave on the center leg of the fets is normal for 1 second then starts to looks like this.
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That looks like the low side.
Didn't you say that the amp worked normally with only the original good inductor in the board (other inductor out)?
Didn't you say that the amp worked normally with only the original good inductor in the board (other inductor out)?
But it's not the center leg. It's the source leg, correct?
Without the inductors, do you still get rail-rail oscillation as you did post #110?
Is the amp going into protect with the inductors in the circuit?
Without the inductors, do you still get rail-rail oscillation as you did post #110?
Is the amp going into protect with the inductors in the circuit?