Here's my .02. Take it out, wire up the ground and the two positive leads to a battery on your bench. Nothing else. Turn it on, see if it works ok with no speakers even hooked up. Then disconnect the power, hookup one speaker and try it again. I would be willing to bet you have 12 volts going into the unit on a speaker wire. If it all works ok on the bench, Take all the old wiring out and start fresh. That will get you squared away. If you have the problem on the bench, you know it another junk radio.