Just wondering on what tests I need to do.
Thanks
Thanks
Thanks. I have run the tests, and here are the results. Before you responded I changed back R28,R29,R36,R37 to the original spec'd values of 15R, to test, but made no difference either. But I left them in place during this test. Also here is the input to output voltages at different levels, I was able to run up the voltage to within 1V of the rails during both tests.Heres is what I suggest you do (no load connected to the output)
1. Power up the amp
2. set the lab PSU to 0V and connect it to the input (the amp is DC coupled) through a 10k resistor
3. Adjust the lab PSU voltage up slowly while monitoring the output voltage of the amp. It should increase linearly with the input voltage
4. Given what you have noticed with the sine wave output, when the output jumps to the V+ rail, stop adjusting the lab supply
5. Now measure all the voltages marked in RED on the circuit diagram plus the voltage drops per post #2646 above
Repeat the above procedure but setting the lab supply so the amplifier output goes negative (if the supply is fully isolated, you can just swap the + and - leads to the input)
Hopefully at this point we can then try to isolate the issue.
Here is the +DC input voltages, I will get -DC input voltages this afternoon. ThanksOK - can you then repeat the test, but measure the voltages across R28 and R29 and across R30 and R31 with each increment of the input voltage. Seems one half of the amp is turning off. You will need to do this with a -ve going DD input signal as well.
Let me look at this again tomorrow- I’ve bern busy today.I've ordered Rev 2.0 PCB's and expecting delivery soon, I may just start from scratch.
Ok no worries. ThanksLet me look at this again tomorrow- I’ve bern busy today.