Dark e36 Radio Display

Let's see, this car needs a half-dozen minor repairs.  Which one does not require any money?

It is decided then.  Today we fix the radio display.

I understand that there are a couple of different failures that can cause the display to be dark, but both of my e36s had this same problem, so the second time I did the job, I decided to take some pictures.

Dark Radio Display
If your radio looks like this one and you can tell what station you are on only if the sun shines on it at just the right angle, these instructions may help you.

Step 1 - Parts and Tools Needed:
  1. 30W soldering pencil.
  2. Fine electrical solder.
  3. Exacto knife or razor blade or a needle to scrape varnish from around solder joints.
  4. This last tool is optional if the screws attaching your radio are not too tight, but if they are as tight as they were on my first e36, nothing but this special 5-sided allan wrench will get them out.  Some folks have been able to jamb other tools into those fasteners and get them loose.   You can buy this tool on line from BMW specialty websites.  I got mine for about $5 from a guy who makes them at home and used to advertise on eBay.
  5. Radio Removal Tool

Losening Radio
Step 2 - Flip open the little doors at either end of the radio face, and using whatever tool you have that will fit, loosen these clamp screws as far as they will loosen.

Releasing Plug
Step 3 - Pull out the radio, unplug the two antenna leads, and pry up on the latch that secures the main plug on the back of the radio.  Even after this latch is fully pulled up (about 3/4"), you have to pull and pry really hard to get this plug off.  

Remover cassette
Step 4 - Remove the top cover (4 screws) and take out the cassette player (4 more screws).  A magnet is handy because these screws tend to fall into cracks.
On my first one, I had read enough on the Internet to know that I was likely looking for bad solder joints.  At this point, I took the radio back to the car and plugged it in and turned it on.  Then I poked things with a toothpick until the radio display flashed on.  Then I knew that I had found the problem.  On my second one, I could see through my magnifying glass that the same solder joints had failed so I did not need to take the radio back to the car.

Remove Face
Step 5 - Since you have already removed the screws that held on the top cover, the only thing holding the face on the radio are these snaps all the way around the perimeter.  There is one electrical plug near the volume control that is easily unplugged from the circuit board once the face is loose.

Bad solder joints.
Step 6 - On both my e36s, the solder joints on these tiny surface mount resistors with the number 180 on them had failed.  Use a needle or exacto knife to clean up the solder joints before you freshen them up with a sharp soldering pencil and fine electrical solder.

Working Display
After freshening the solder joints, put it all back together and - Voila!    Now, where did I put that card with the radio code?.