Radio output suddenly distorted

The radio with 6-disc CD changer in my '02 Explorer.

This unit has worked well since Day 1, until recently when the audio
developed a kind of frog-in-the-throat distortion. Since the problem
happened on all four channels simultaneously, I don't think I've blown a
speaker, nor have I popped an amplifier output stage, nor is it a wiring
problem. In addition, the distortion is present on both AM/FM and CD
audio. That doesn't leave too much that could have failed. I'm guessing
that one of the power supply filter caps has gone bad, but I'm certainly
willing to entertain other guesses.

Before I pop the radio out of the dash and start troubleshooting, it
would be handy to have a schematic for it. Is such a thing available?
BTW, I'm an electrical engineer, and work on antique radios a lot, so I
am reasonably confident of my basic troubleshooting ability and my tool set.

Thanks

Bill Jeffrey

Bill Jeffrey wrote:
> The radio with 6-disc CD changer in my '02 Explorer.
>
> This unit has worked well since Day 1, until recently when the audio
> developed a kind of frog-in-the-throat distortion. Since the problem
> happened on all four channels simultaneously, I don't think I've blown a
> speaker, nor have I popped an amplifier output stage, nor is it a wiring
> problem. In addition, the distortion is present on both AM/FM and CD
> audio. That doesn't leave too much that could have failed. I'm guessing
> that one of the power supply filter caps has gone bad, but I'm certainly
> willing to entertain other guesses.
>
> Before I pop the radio out of the dash and start troubleshooting, it
> would be handy to have a schematic for it. Is such a thing available?
> BTW, I'm an electrical engineer, and work on antique radios a lot, so I
> am reasonably confident of my basic troubleshooting ability and my tool set.

Yeah, I think you got it- a power supply problem affecting the audio
amps. I have a DVD with schematics, but they don't get down to the
component level in the radios.

You could pull the radio and look for the usual- an electrolytic
capacitor with a bulging end, but you're probably just going to need to
replace the radio.
-Paul