I picked up a Fisher 203 last week at tag sale and it looked in good shape. When I powered it on and hooked up speakers to test it makes a loud crackling noise even when the volume is on the lowest setting. I took off the top and bottom covers and blew out all the dust and then cleaned all the controls with contact cleaner twice and blew out entire unit again. It still has very loud crackling noise when volume isn't turned up and I can barley get any sound from the radio, but then crackling get even louder.
Any thoughts on the problem?