roundel
07-09-2013, 07:11 PM
The led lights that backlight the radio display on E36 radio head units are prone to fail over time. A common cause of this failure are two little surface mount resistors on the circuit board. I used the directions below (borrowed from Bimmerforums) to fix my stereo display:
What you'll need:
A soldering iron, preferably with a fine tip.
Thin solder
A smallish philips head screw driver
A flat blade screw driver
Needle nose pliers
A multimeter
The security code for your radio
First of all you need to pull your radio from the car. There are little hinged tabs on each side of the radio. Pop them open. The screw in here has 5 sides, but you can make a hex wrench work fine. Unscrew as far they'll go and jimmy the head unit out. For those with an M3 you can substitute a hard 1-2 shift at the redline for the jimmying, the radio will slide right out. Ask me how i know. Disconnect the big black connector by following the disgram on the top of it. You'll have use some force with the screw driver when prying it up, it will make a real ugly sound when it pops off, but everything is fine.
Next take the plastic cover off. There are 2 screws, one on each side, near the top, towards the front of the unit. Then there are tabs near the bottom that need to be pushed in as well as one on the top that also needs to be pushed. Everything else is kind of a prying exercise
Now we need to take the top cover off of the unit. Two screws in the back, toward the top need to come out. Then it just pulls off.
Next stop is pulling the display circuit board out. There are 2 screws attaching it to the tape player assembly. Then there are 2 metal tabs on the side of the unit that need to be pushed in. Make sure you disconnect the little socketed wires for the volume knob on the left side of the unit. There's a black piece of wire holding it in place that serves no other purpose and is safe to bend. Now you should be able to pry the displayboard clean out. Set it aside.
The tape player now needs to be removed, there is one screw on the left side near that beige plastic thing and one on the right side down a square hole. Then just pull the entire assembly up, set aside.
You have now arrived at the main board, the source of all your problems. Time to head back your car with the unit, the front display circuit board and your multimeter. Plug that wired volume button back into the main board, and plug the unit back into the car. Put your keys in and turn on the electrics in the car. Now push the volume button in to turn on the stereo. You need to figure out if those bulbs under the display are even getting any power,Toward the front of the unit you will see 2 red connectors. Looking at unit head on, the socket on the left and the last pin hole all the way to the left is the one that powers the bulbs under the LCD. You should get just under 12v on your multimeter from it. I pull up the ciggarette lighter connector and use the ground under it for my ground.
IF YOU DON'T GET POWER FROM THAT PIN (scroll down for instructions if you do)
Head back inside with your radio. Disconnect the volume dial again. Take a look between those 2 red connectors again. In between them you will find a couple surface mount resistors. They are litte black rectanges with the number "180" on them. These have cracks in the solder on each side of them too small for the human eye to see. What you'll need todo is just touch up these joints (4 joints total) with alittle solder.
Now repeat the above paragraph and make sure you're getting 12V now. Turn off the radio, reattach the display board, including plugging the pins back into those red connectors. Turn radio back on. Does your display light up nice and bright now? Good! You're done! ......if it doesn't proceed to the next section.
IF YOU DO GET POWER FROM THAT PIN
This means those bulbs under the display are likely burnt out.
Extra stuff you'll need:
Copper desoldering braid
2 8v microlamps available at partsexpress.com
You'll need to remove the metal backing from the display circuit board. There are 2 metal tabs holding it by way of holes in the circuit board, desolder these tabs from the board and bend the tabs back. The display board should come off fine now.
Now removed the actual LCD display, again, more tabs to desolder, 3 along the top of the LCD, one of which is through the circuit board. Then 3 more along the bottom, but these may not be soldered, you probably just have to bend them back, Removed the display and you'll see the bulbs. Desolder them and resolder in the new ones. Go out to your car and make sure they work. If they don't, I don't know what to tell you, this all worked for me, Very sorry.
If it did work, congrats, reassemble your radio and enjoy!
What you'll need:
A soldering iron, preferably with a fine tip.
Thin solder
A smallish philips head screw driver
A flat blade screw driver
Needle nose pliers
A multimeter
The security code for your radio
First of all you need to pull your radio from the car. There are little hinged tabs on each side of the radio. Pop them open. The screw in here has 5 sides, but you can make a hex wrench work fine. Unscrew as far they'll go and jimmy the head unit out. For those with an M3 you can substitute a hard 1-2 shift at the redline for the jimmying, the radio will slide right out. Ask me how i know. Disconnect the big black connector by following the disgram on the top of it. You'll have use some force with the screw driver when prying it up, it will make a real ugly sound when it pops off, but everything is fine.
Next take the plastic cover off. There are 2 screws, one on each side, near the top, towards the front of the unit. Then there are tabs near the bottom that need to be pushed in as well as one on the top that also needs to be pushed. Everything else is kind of a prying exercise
Now we need to take the top cover off of the unit. Two screws in the back, toward the top need to come out. Then it just pulls off.
Next stop is pulling the display circuit board out. There are 2 screws attaching it to the tape player assembly. Then there are 2 metal tabs on the side of the unit that need to be pushed in. Make sure you disconnect the little socketed wires for the volume knob on the left side of the unit. There's a black piece of wire holding it in place that serves no other purpose and is safe to bend. Now you should be able to pry the displayboard clean out. Set it aside.
The tape player now needs to be removed, there is one screw on the left side near that beige plastic thing and one on the right side down a square hole. Then just pull the entire assembly up, set aside.
You have now arrived at the main board, the source of all your problems. Time to head back your car with the unit, the front display circuit board and your multimeter. Plug that wired volume button back into the main board, and plug the unit back into the car. Put your keys in and turn on the electrics in the car. Now push the volume button in to turn on the stereo. You need to figure out if those bulbs under the display are even getting any power,Toward the front of the unit you will see 2 red connectors. Looking at unit head on, the socket on the left and the last pin hole all the way to the left is the one that powers the bulbs under the LCD. You should get just under 12v on your multimeter from it. I pull up the ciggarette lighter connector and use the ground under it for my ground.
IF YOU DON'T GET POWER FROM THAT PIN (scroll down for instructions if you do)
Head back inside with your radio. Disconnect the volume dial again. Take a look between those 2 red connectors again. In between them you will find a couple surface mount resistors. They are litte black rectanges with the number "180" on them. These have cracks in the solder on each side of them too small for the human eye to see. What you'll need todo is just touch up these joints (4 joints total) with alittle solder.
Now repeat the above paragraph and make sure you're getting 12V now. Turn off the radio, reattach the display board, including plugging the pins back into those red connectors. Turn radio back on. Does your display light up nice and bright now? Good! You're done! ......if it doesn't proceed to the next section.
IF YOU DO GET POWER FROM THAT PIN
This means those bulbs under the display are likely burnt out.
Extra stuff you'll need:
Copper desoldering braid
2 8v microlamps available at partsexpress.com
You'll need to remove the metal backing from the display circuit board. There are 2 metal tabs holding it by way of holes in the circuit board, desolder these tabs from the board and bend the tabs back. The display board should come off fine now.
Now removed the actual LCD display, again, more tabs to desolder, 3 along the top of the LCD, one of which is through the circuit board. Then 3 more along the bottom, but these may not be soldered, you probably just have to bend them back, Removed the display and you'll see the bulbs. Desolder them and resolder in the new ones. Go out to your car and make sure they work. If they don't, I don't know what to tell you, this all worked for me, Very sorry.
If it did work, congrats, reassemble your radio and enjoy!