On-Board Computer light improvement

The OBC lightbar in all E30 BMWs will need replacement from time to time.  Extraction and replacement of this component is labor intensive and a real PITA for what amounts to changing a light bulb.  
There is a way to do this only once, replacing the little incandescent bulbs with LEDs, which are extremenly long-lived, and this upgrade will probably outlast the car.


I used bright white LEDs, which can be obtained at a Radio Shack.  These are wired in series, with a 150 ohm resistor.
Observe the polarity of the diodes.  The longer lead is the + side.  The resistor fits comfortably on the side of the board, on the underside of the lightbar.

I attached pieces of white paper behind the LEDs to reflect light.  The leads go through the same openings as the original bulbs, which have been unsoldered and removed.  They are also in series, so if one burns out, neither will light.



The lightbar will work with the dimmer, but may go out at very low levels.  This may not be a problem as most BMW owners I know use the instrument lamp setting at the higher levels.
I believe in progress, which may be defined as the simplification of tasks, maybe to the point to where they are no longer necessary.  By that standard, I believe this upgrade may qualify.  As long as engineers make it hard for components to be serviced, we can make those components last for a lifetime.


Contact:  drautox@comcast.net