I've got the power supply up and running and I have the correct rail voltages but I cant get it to oscillate even when I drive a sine wave into it. I've replaced both 21844s chips twice and checked all of the a1715 and c2814 transistors.
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Are you seeing the drive on the output terminals of U3 and U4?
Is the opto-coupler that's in front of the driver board shorted from terminals 1-2? From 3-4?
If the marking behind the driver board tell the pin configuration, post a photo of them.
Is the opto-coupler that's in front of the driver board shorted from terminals 1-2? From 3-4?
If the marking behind the driver board tell the pin configuration, post a photo of them.
No I am not seeing any drive on u3 and ur
The opti-coupler is not shorted
No marking behind diver board
The opti-coupler is not shorted
No marking behind diver board
Have you operated all pots and switches through their entire range while monitoring the output of U4 to see if the signal ever passes through to that point?
That's normal. To have high-side drive, you either have to supply high-side voltage with an isolated power supply (I use a 9v battery) or install the FETs.
5v measured with a multimeter or 5v of amplitude as seen on a scope?
5v measured with a multimeter or 5v of amplitude as seen on a scope?
I'm sorry but that means nothing.
Did you see a waveform that was 2 divisions tall with the scope set to 5v/div? Or was it only 1 division tall on 5v/div?
Did you see a waveform that was 2 divisions tall with the scope set to 5v/div? Or was it only 1 division tall on 5v/div?
If you don't take the time to clearly explain what you're seeing (in detail),it makes it difficult to help. We're working blind. All we have is what you give us. Post a good quality image of the waveform showing what you have and include the scope settings, including probe 1/10x setting.
Ok so when I play a sine wave without the fets in I see the signal on the gate pads on the low sides but when I put the fets in the signal is gone. Nothing is heating up and it idles at 4 amps.
If the signal is on the gate pads for the fets doesnt that mean there is signal on the drive ic's?
You have to have them in both banks.
It's important to know if the drive disappears when the FETs are in the circuit.
It's important to know if the drive disappears when the FETs are in the circuit.