92 S500 radio making weird noises. IE, loud high pitched tone/crackle
 

My 92 S500's radio started making a loud high pitched tone and/or crackle.
If I turn off radio then turn back on it will work fine for another 10-15min or 10-15 sec. Has anyone had this happen to them? Dont know where to start.
Thanks. Jay

PS. I'm in Canada and we started using the S500 tag in 1992.
Dont want anyone to think I have the year or model posted wrong.:)

My wife's '95 C car had the exact symptoms, and it was the amp in the trunk going bad. Try to isolate it to one speaker, I think that would prove it.

Its the front drivers side dash speaker. How do I test amp?
Thanks. Jay

I don't know the specifics of testing it with a meter, but the fact that one speaker is out points to the amp. If your two piece radio is basically the same as the later one piece, the radio doesn't have an output for each speaker. The amp separates it.

Speaker is not always out, only goes out when the high pitch tone and cracking starts.
Thanks.Jay

It's typical for the amp to go out when hot. That's what ours did and sounds like that's the case with yours.

Found this site. Going to have my buddy look at it for me. It says the capacitors might be dried up.


Mercedes w140 Bose amplifier rebuild

I have a Bose Amp in case you need one.
I can get the part number if interested.

There are two generations of the amp:

This should answer your questions.

MBCluster.com Mercedes W140 Instrument Cluster Repair Homepage

It is a pain to unsolder each amp module on the old style, but it can be DIY'ed

Here is a DIY:

W140 BOSE AMP Rebuild - Benzworld.org - Mercedes-Benz Discussion Forum

Best of luck,

Martin

The plug looks the same on the later stile amp. Has anyone tried to use a amp from a 95-99 part number 140 820 22 89, with a 92-94 that calls for a amp with part number 140 820 00 89.