right front channel cutting out - PeachParts Mercedes-Benz Forum

jsmith · #1 03-30-2002, 05:11 PM

a couple of times i've noticed that my right front channel is out. when that happens, i switch the balance to the right and the fader bias to front and then turn up the volume. the channel then sputters to life and sound is normal again. is this indicative of impending amp failure? what does it cost to trade in the amp for a new one?

cheers

Crew · #2 03-30-2002, 08:44 PM

I'm having the exact same symtoms... Left channel is totally out upon start up. Then slowly sputters back to life after 10-20 minutes. Also, when changing stations via the presets, a popping/snapping sound comes from the speakers... This also goes away over time???? I checked the AMP at the dealer by simply plugging in a rebuilt AMP they had in stock... No difference.

Crew

jsmith · #3 03-30-2002, 08:48 PM

might be different in my case. it was behaving this way with the Becker 1432 and now my new Alpine head unit. the system is only two channels and i know i'm getting juice out of both channels from the headunit so it's gotta be the amp. in your case if a rebuilt amp is doing the same thing, i would try another headunit....

SCLJA · #4 03-30-2002, 09:21 PM

Joe the simple test in your car is to go to the trunk where the amps are and switch the plugs from one to the other and if the problem changes side then you will know for shure if it is the amp. I sell fully rebuilt amps for $175.00 through my repair shop if you are interested.

Scott @lajollaaudio

jsmith · #5 03-31-2002, 07:50 AM

Scott,

I'm a little confused. If it's the amp, switching the inputs to it won't change the fact that the right front channel is dying right? If I bias the fader to the rear, I get sound from both sides. I am using the factory wiring, feeding a pair of my speaker outs into the factory amp.

Thanks

SCLJA · #6 03-31-2002, 04:09 PM

If it is the amp then the problem will move to the other side. The amps are configured so one amp is running the left front and left rear and the other amp is running the right front and the right rear. If you switch the amps and the problem stays on the right side then the problem is either going to be in the fader control or the speakers. When I install an aftermarket radio I use the speaker outputs but I use a PAC adjustable high to low adapter that helps to match the input level to the factory amps. I can imagine the stock fader control could be giving out with too much power going through it. They also get dirty and it causes this type of problem.

Scott@lajollaaudio

jsmith · #7 03-31-2002, 06:25 PM

you mean switch the output of the amps then. is there an easy way to do that? there is a big rectangular wiring harness that plugs into the amp and the speaker wires are all wired from that. are there pinouts somewhere or color coding that will help me identify which is which?

i tried to work the fader to eliminate contact problems and that didn't really do anything. it's when i turn up the volume to the right side when the amp "wakes up". ..

Ashman · #8 03-31-2002, 07:01 PM

I would start checking alls peaker connections myself. sometimes a loose speaker connection can cause this.

I have seen this happen with aftermarket stereo's and bad RCA connectors. I have had first hand experience with it just last week in my car. a bad rca end causes sound to chop out on one side. A little solder and a new end, and I was back in action.

Alon

SCLJA · #9 03-31-2002, 07:23 PM

Just switch the connectors as they are identical and this will tell you if it is the amps or not.

Scott

jsmith · #10 03-31-2002, 07:54 PM

Scott,

we are talking about the amp outputs right? the only connectors i have that are easily switched are the inputs which are hooked up to the speaker outs of my headunit. the amp output is a rectangular wiring harness that has 6 pairs of speaker wire in it. can it be reversed?

if i switch the inputs that won't tell me anything, because right front is still right front as far as the amp is concerned.

if i switch the outputs then that would give me the diagnosis that you are indicating, but there is no easy way to do it (or is there?)...

SCLJA · #11 03-31-2002, 10:30 PM

Joe if you plug the right amp into the left and left into the right and if the problem moves to the left side then this will tell you the problem is in the amp if it stays the same then it is in the fader or speakers. Don't worry the amp plugs are interchangeable. The front speaker wires are gray and gray black.

Scott

jsmith · #12 04-01-2002, 08:56 AM

Scott,

They are all wired into this one plug and it's directional so I can't just reverse it. Can I pull out the wire/pins and switch them?

Thanks

SCLJA · #13 04-01-2002, 09:49 AM

I didnt realize you have the single amp system. Most 93 124's have a dual amp system and the plugs are reverseable. This amp just runs the door speakers and the radio power runs two channel through it and then to the fader control and 4 ch out of fader to the front and rear speakers. If you don't have a problem with the rear right also Iwould have to say the problem is in the speaker or connection.

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