Is the pulse width of the PWM signal on the carrier going from near 0% to near 100%?
If not, the problem is the signal driving the input of the class D circuit.
It doesn't seem to be, the layout of the 3 quad package op-amps has me baffled. A few have a square wave on the outputs while others have a triangle waveform and a few have the sine wave input signal.
I would say, that could be input stage of clocked amp... triangle waveform + sine wave = pwm
what is the freq. of triangle waveform?
I'm guessing the frequency to be 40-80khz, I don't have it in front of me and basing it on my scope settings that I remember.
The amp requires that the input signal be equal to or greater than the amplitude of the triangle waveform to drive the amp to clipping. If the signal has an amplitude lower than that of the triangle waveform, the problem is in the preamp circuit, possible in the muting circuit (if it has one).
Gate signals look good, just don't know why the output is not right.
Gate signals with no input signal.
5V/div
50V/div
Gate signals with no input signal.
5V/div
An externally hosted image should be here but it was not working when we last tested it.
50V/div
An externally hosted image should be here but it was not working when we last tested it.
It appears that you have a defective output filter (either the capacitor, inductor or both).
You didn't include the timebase setting so I'm assuming that it's set to 5-10us.
Are you using a differential probe setup to view this signal?
Does it appear to be trying to produce audio?
You didn't include the timebase setting so I'm assuming that it's set to 5-10us.
Are you using a differential probe setup to view this signal?
Does it appear to be trying to produce audio?
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