1999 Rx300 Radio Is Giving Me Some Attitude

[RobRX300]

My radio/CD/cassette has stopped working. At first, the passenger side speakers would cut out, but if I briefly turned the volume up, they would come back on and stay on for a while. Then, no sound at all, other than some faint static that would get louder if I turned the volume up. After following other posts on the forum, I concluded it must be the amplifier. I replaced that with a used model from Ebay, no change. Then, I replaced the radio with another used unit from Ebay, no change. Except, I noticed beyond the static, I could hear the radio or a CD playing. But it was very faint. My car has 400K kms, runs great, but if I can't have a radio it may have to go. Anyone have any ideas ? Thanks.