The current draw increases significantly when a load is attached. I say "significantly" because I now have a 2A current limit on it. When I attach the load it maxes out and the supply voltage drops to ~9vdc. When I had the current limit set to 4.5A, it maxed that out.
The resistance between the relay input and the high side source is .1 - .2 ohms. I have to hold the probes there for a few minutes to get it to steady reading.
The resistance between the relay input and the high side source is .1 - .2 ohms. I have to hold the probes there for a few minutes to get it to steady reading.
Wow! I connected my larger power supply without any current limiting and using the 50Hz input signal and the amp draw first jumped up to ~16A and then fell and stayed around 9 - 10A.
The output signal looks good at the speaker terminals. Looks like that op amp at U13 was the problem. Before, when using my large power supply is when I originally discovered the problem.
I am going to mount it back into the heat sink and see how it does unless there is something else I should check first.
The output signal looks good at the speaker terminals. Looks like that op amp at U13 was the problem. Before, when using my large power supply is when I originally discovered the problem.
I am going to mount it back into the heat sink and see how it does unless there is something else I should check first.
I believe that I can see it when I change the scope to 100 - 200mv/div.
The noise remains constant regardless of position of pots.
I attached a screen shot of the noise at the speaker output.
There is one of the op amps in the pre-amp section that has 15 vdc on pin 7. None of these op amps have board designations that I can see.
The noise remains constant regardless of position of pots.
I attached a screen shot of the noise at the speaker output.
There is one of the op amps in the pre-amp section that has 15 vdc on pin 7. None of these op amps have board designations that I can see.
