The dreaded missing pixels

Well, one of the E39 diseases has infected my '03 530i. The dash display
has several lines of missing pixels in the trip odometer and OBC displays.
I know this is not uncommon and I will probably replace the thing under
warrantee. (If it happens outside of warrantee, there's a shop specializing
in the repair.)

Still, I'm curious. Does anybody know the cause for this malady? It seems
intermittent ... lost a line of pixels, then they came back, then several
went out, etc.

R / John

It's just the connections to the individual pixels if it's intermittent.


"John Carrier" > wrote in message
...
> Well, one of the E39 diseases has infected my '03 530i. The dash display
> has several lines of missing pixels in the trip odometer and OBC displays.
> I know this is not uncommon and I will probably replace the thing under
> warrantee. (If it happens outside of warrantee, there's a shop
> specializing in the repair.)
>
> Still, I'm curious. Does anybody know the cause for this malady? It
> seems intermittent ... lost a line of pixels, then they came back, then
> several went out, etc.
>
> R / John
>

A BMW tech showed me this once - there's a flexible wire bus which connects
to a circuit board. Each wire in the bus corresponds to one column (or row)
of pixels. Over time, the contacts become intermittent.
Apparently the way the bus was soldered/glued/whatever to the circuit board
was insufficient to stand up to the real-life conditions of car usage.

AFAICT, the board isn't subjected to a lot of vibration or heat cycling,
so maybe the original contacts were just adhered in a less-than-robust method.

-Ted

---- orig msg ----
>> Well, one of the E39 diseases has infected my '03 530i. The dash display
>> has several lines of missing pixels in the trip odometer and OBC displays.
>> I know this is not uncommon and I will probably replace the thing under
>> warrantee. (If it happens outside of warrantee, there's a shop
>> specializing in the repair.)
>>
>> Still, I'm curious. Does anybody know the cause for this malady? It
>> seems intermittent ... lost a line of pixels, then they came back, then
>> several went out, etc.


>>
>> R / John
>>
>
>

Agreed. But the problem is well known. Still, the board (and everything else
in the car) is subject to vibrations and temperature changes in the course
of daily driving, summer/winter temperatures, etc.



"Ted Johnson" > wrote in message
...
>A BMW tech showed me this once - there's a flexible wire bus which connects
> to a circuit board. Each wire in the bus corresponds to one column (or
> row)
> of pixels. Over time, the contacts become intermittent.
> Apparently the way the bus was soldered/glued/whatever to the circuit
> board
> was insufficient to stand up to the real-life conditions of car usage.
>
> AFAICT, the board isn't subjected to a lot of vibration or heat cycling,
> so maybe the original contacts were just adhered in a less-than-robust
> method.
>
> -Ted
>
> ---- orig msg ----
>>> Well, one of the E39 diseases has infected my '03 530i. The dash
>>> display
>>> has several lines of missing pixels in the trip odometer and OBC
>>> displays.
>>> I know this is not uncommon and I will probably replace the thing under
>>> warrantee. (If it happens outside of warrantee, there's a shop
>>> specializing in the repair.)
>>>
>>> Still, I'm curious. Does anybody know the cause for this malady? It
>>> seems intermittent ... lost a line of pixels, then they came back, then
>>> several went out, etc.
>
>
>>>
>>> R / John
>>>
>>
>>
>
>