Good day. I am working on an Orion 2500D for sometime now. It produces a high pitch whistle sound upon power on, and it takes around 30 secs then goes down but not totally gone. I had re soldered the output FETS that where loosed maybe because of vibration causing the switching signal to go on and off, but it did not solved the issue. Gone to days of checking the parts and signal but found no defective parts and signal from supply to output is normal as far as I am concern. Note that The amp is working normally when fed with audio. I had read a couple of threads of the same problem but all of them had no resolution in the end. Did anybody found the solution of this issue at this point of time? please share. I will appreciate it much. Attached is photo of the model.
