21-09-2018, 08:14 PM
To cure the switch off oscillation you will need to look at the smaller transformer in the PSU as one of the power rails generated there is decaying first when it is powered down causing one stage of the amplifier to briefly change from inverting to non inverting so that the NFB line goes positive.
You could briefly power down the small transformers to see what happens or add extra capacitors to the rails they create.
I am assuming that the second item that looks like a transformer is a choke.
You could briefly power down the small transformers to see what happens or add extra capacitors to the rails they create.
I am assuming that the second item that looks like a transformer is a choke.
