Crappy Screeching Stereo

[mr2mk1g]

Ok, I’ve posted this before, (here and a couple of other sites) and not had anyone come up with an idea.

My stereo is being really weird. I know it’s not the head unit as I’ve had two different ones in there (both sony). I know it’s not the media type as it does it with MD, CD and radio. I know the Speakers themselves aren’t shot as when it works fine they are crystal clear. I guess that kinda leaves the amps.

I’m running all stock but for the head unit, which puts out at 50watts (other one I’ve had in there outputs at 45watts). Head unit's connected via the individual pre-outs not the twin block connector thingy. The stock sound system is the one with one sub behind the passenger seat and tweeters by the mirrors. It only exhibits problems when it’s cold although it can often take an hour or so to clear fully whilst sometimes it clears quite quickly.

The problem sounds kinda like a scratched CD, a kind of interruption in the sound coupled with a split second of fuzz. At first it happens every second or so and makes it almost impossible to hear the stereo. If I crank the volume a bit the sound sometimes goes screwy completely for a moment and a I hear a screeching sound starting high pitch and lowering till it clears after 3-5 seconds. The problem slowly decreases in frequency till I get a perfect stereo again.

It sounds really weird and is really really annoying. I figure I’m going to be ripping the lot out at some point but have a couple of more important purchases first so if anyone knows a less drastic fix or at least has an idea as to the cause, please go ahead.

Cheers.

[Bobby-H]

Have you checked that your head unit is earthed properly, I've heard that the standard earth conection on the wiring loom for the stereo isnt that great especially if the stereo is drawing a lot of current. It might be worth running an extra earthing wire to the case of the head unit.

[Karma Supra]

Mine is doing it too.. stock speakers/subs/amps... Sont headunit... when ever I turn off the ignistion there is some kind of discharging screech... recently when listenign I get a background screech and the left hand side Speakers drop out :( I'm using an auto leads adapter for the Speakers..

[BLOODUK]

Still using the stock amp in the mr2 then rewire the Speakers direct to the headunit , wolla screaching gone

[DeusMR2]

this is an old problem that i had aswell with my sony headunit. What you need to do is connect the SPEAKER grounds and the HEADUNIT ground together. Voila no more screeching noise (which is actually from the power steering pump)

If you have an autoleads adaptor with the RCA cables then what you do is split the insulator on them, take out the ground wires from each (the bare wire that goes around the core), connect them together and connect them to the ground lead from the ISO connector; it seems a bit silly having to open up a £30 autoleads adaptor but it works perfectly now.

[Bibbs]

heh heh .. all Sony ..

[mr2mk1g]

Still using the stock amp in the mr2 then  rewire the speakers direct to the headunit , wolla screaching gone

That's what I've done on my previous two toyotas (mk1 and supra) - never had a problem with them. When I opened up the dash on this one to stick my head unit in I found some garage had butchered the wires and the standard loom had gone to be replaced by less than half as many individual wires with phono plugs and a couple more into a sony block. Really annoying.

Can't be the power steering pump either as it's a Rev1 and doesn't have it.

I'll whack another ground in and see if that solves the problem easily.

[BLOODUK]

hehe atleast you could get your headunit out , some ****** welded this headunit to the car frame