I have been rebuilding an eagle 500 That is in fairly nice condition, all original with original tubes. I have replaced 80% of the capacitors the only ones left are the silver mica caps in the final drive section. I have replaced the transistors for the preamp and ssb circuit but i still am getting a real bad squeal when used on the ssb side, I'm assuming it is feedback somewhere but I'm running out of ideas on where this squeal is coming from The amp works great on the am side it will put out 500 watts easy. I still have to replace the diodes on the transformer board but i don't believe that is the cause of the ssb squeal. Any ideas on what part of the circuit is most likely to be causing this feedback Radio transmits great on ssb until you run it through the amp.I still have not changed the resistors in the ssb circuit yet but most of them have tested fairly good.