I have a 750il stereo system...

[Whit]

I thought my car was a '94. With help I got here, I discovered that it is actually an '88 750il from Japan with some monkey business to the title! Arggh! I guess I will change my forum signature here soon. However, the car is wonderful and I got a great deal here in the Philippines. It is like new, so I am actually not that upset--I underpaid and it is a great car. Everthing works! Almost.
So...I am staying positive. The one issue with the car is the stereo system for the 1988 750il. It is made by Sony. It has never worked, but the head unit, changer, rear controller, and speakers are there. All the DIN cables are in place, but wires (for speakers?) have been cut in the trunk. The previous owner told me the radio did not work because of a blown fuse (NOT!), but I want to control tunes front and back with the factory system.
Are there amplifiers in the car? If so, where are they? If not, do the speakers get power from the head unit? How is everything laid out? Sorry for all of the questions. As a younger man, I used to be a car stereo installer, but I can't just rip apart the whole car--it is our only car while we are here. I bought it because I knew if the only thing wrong was the stereo that I could fix it easily. Ooops. Maybe someone could save me some time? Help!

[shogun]

There is some info on the 5 series board where I am asking for a owners manual of a Sony audio. I do not know if it is the same, as you do not indicate any type and model. Have a look at that thread.
If it is the same, the I have got the following info.:

It was not fitted to any vehicles destined for any markets outside of
Japan,
due to the fact that the FM frequency range is 76-90. That means Japan,
Japan, and only Japan

So never fitted in Europe, or Singapore, or Hong Kong, or USA, or NZ, or

Aus. (because all these countries have 88-108 like we do)

If it has standard black square BMW connector on the rear then the
cabling
is:
Large multi-pin connector

1 = Loudspeaker, front left, +

2 = Loudspeaker, front right, +

3 = Loudspeaker, rear left, +

4 = Telephone mute

5 = +12V ignition

6 = Loudspeaker, rear right, +

7 = not used

8 = Loudspeaker, front left, -

9 = +12V battery

10 = Speedo signal for speed sensitive volume

11 = Loudspeaker, front right, -

12 = Loudspeaker, rear left, -

13 = Illumination

14 = Loudspeaker, rear right, -

15 = Ground

16 = Automatic antenna or on-glass antenna amplifier or sound Hi-Fi
amplifier

17 = not used


--------------------------
Model Manufacturer: Sony
Model Number: CDX-5B817

To find a manual, you can try
http://www.partsolver.com
Sony Japan does not have one.

One thing is very important. the speed signal cable. If you mishandle that, you will have problems.
Check also with Sony online dowloads
http://esupport.sony.com/

More details from the 5 series board here on my Sony
http://www.bimmer.info/forum/showthread.php?t=9640

[Whit]

Shogun, thanks for all of that. I should have mentioned that the wires and harness in the dash are intact and not cut. No cuts in the cable (DIN style with pins) in the back seat armrest. Intact.
I am actually wondering about the hookups in the back. I am thinking this is just a 4-speaker system powered by the head unit. It has no amplifiers, correct? In the trunk, it looks like an antenna male plug (or similar), with cut speaker wires(but the color codes are there) and an intact cable with pins in trunk. I think if I plug everything in and wire up the speakers, it may work.
Just to be clear, there is no hidden factory amplifier in this car, right?

[Paul in NZ]

i bet the 750 has an amplifier,in the e34 it is behind the trunk lining on the lhs(looking in to the trunk from behind the car)

[shogun]

drivers side and also behind passenger side I have something. The amplifier is also at the same time in charge for rear window heating.
And it depends on what you have : antenna or antenna-diversity, or even with telephone.

click on the pics to see the functions and places
Be careful when removing the cover. The lower clip breaks easily and then you have to 'weld' it like I had to do when replacing my geadliner

Pull rear seat sidelights from C pillar casing, rear edge pulls out first.
Through the space you can see (with torch) the top bayonet clip. Put your hand in behind the clip and pull straight inwards. This releases the top of the casing. The problem is that there are two lower plastic clips on the casing that are brittle and fairly easy to break if you rush it. The bottom of the casing is strongly pushed by the back seat so carefully pull the edge of the seat away from the casing and with your other hand as low down on the casing as possible, pull the casing upwards at 20 degrees and forward. You should get both clips out intact.
Unplug the side lamp. That's one done now do the other!

[Whit]

Thanks guys. Strange thing: if either one of the (front or rear) faceplate units is hooked into the dash, it will work and play the speakers. Weird. One did not light up in front, so I used the one that lit up properly. When I plugged the remaining faceplate into the back armrest, the system stopped working and froze up the display. I think there is a short in this one (rear armrest?) unit. I tried reversing them with no luck. Which one really goes where?
The CD changer turns on and takes the disk, but its laser is not working, so that will go to the shop for repair. I suppose I could buy another, but it seems it is the amplifier for the speakers too! At least the speakers plug into it. Crazy! Any of this sound strange?

[shogun]

Front panel

The aux plug hole is at the right side bottom front face

This one is for the rear armrest. There you cannot see the hole in the front for the aux plug. It is underneath and you can plug in from the area where the storage shelf for the armrest is.
That is the difference.
You must make sure that the speed indicator cable is connected. Otherwise it might stay on mute or telephone sound = no sound at all.

I had the problem last summer. No sound at all. All was frozen and it showed volume 5 and aux, but I could not switch anything, no sound at all.
Changed front and rear panel against other ones from a friend, nothing changed. Brought it to Sony with the complete set in the trunk. They could not find anything. Installed it again, after someone recommended to put the into the refigerator for a day, and then it worked again. It was the too high humidity during raining and Taifun season which caused this. Already had this twice in several years always during raining season when we have >90 % humidity.
Here is some info from OJ in Norway, but his audio can be different from yours.
http://ow.no/index.php?option=conten...d=56&Itemid=43

I do not know much about audio equipment, sorry. Maybe there are other experts here.

[Whit]

Thanks! Crazy thing is, mine only works (and lights up) with the back piece in the front dash and nothing connected in the rear armrest! I don't know. The seller had the entire system and wiring pulled and tested. Maybe they reinstalled the cable backward front to rear?
Well, the remaining unused rear piece (or the cable) may have a short. In addition, the CD changer loads but will not read the CD. I think it is just a dirty lens. I will clean it and see.
The system is working on all speakers and I can control it from the front, but I hope to get it to control everything from both front and rear one day. I would be willing to trade the whole setup for non-original equipment that has front and rear controls. Anyone? Maybe someone wants the 1988 750il factory system? In the Philippines, my wife and I have a driver, so it would be nice to have control from the back.
Here is a tip on the "frozen" radio display or volume control: first, just turn the car off and get out. Wait about 60 seconds and get in and restart the car. That "unfroze" mine, so it might work before pulling it and chilling it.

[shogun]

Whit,
is that Sony system the same as shown on the pics from my car?
Might be too expensive to send it to Japan.
But just as a spare unit in case my one fails???

[Whit]

Yes, it looks exactly the same. It has Japanese FM frequencies, as well. It stops at 89.9 on the FM dial.