IPK lines in the display

[HarryM1BYT]

The scrap IPK turned up this afternoon via PAB, so we had a chance to pull that one apart to see if the issue with the lines in the dispaly could be fixed, without risking damaging my own IPK...

Sorry to advise - there is absolutely nothing at all that can be done to repair them.

The small display which shows the mileage, temperature and service - uses conductive rubber strips to make contact with the PCB behind it. I had originally assumed this might be how the IPK display might also connect with the PCB and these conductive rubber pads do often give problems, but I was wrong....

The display which shows the actual lamp which has failed, the Traffic Master, the mpg and etc. - links to the main PCB by a paper thin flexible ribbon cable, which is soldered at each end to display and PCB. My best guess now is that it is the display itself which causes the lines - so nothing can be done. Even if you can get hold of a good replacent display panel, replacing it one be an extremely tricky operation, on top of which opening up the unit to get to it is extremely difficult.

For extra information....
Both displays are LCD and LED backlighted. The lower one uses orange single colour LEDs. The upper one uses bi-colour (red and orange) LED's. Each bi-colour LED is able to illuminate its own section of the rear of the screen - which explains how it can light up with two colours (red and orange), on the screen at the same time.

[David Lawrence]

Originally Posted by HarryM1BYT

The display which shows the actual lamp which has failed, the Traffic Master, the mpg and etc. - links to the main PCB by a paper thin flexible ribbon cable, which is soldered at each end to display and PCB. My best guess now is that it is the display itself which causes the lines - so nothing can be done. Even if you can get hold of a good replacent display panel, replacing it one be an extremely tricky operation, on top of which opening up the unit to get to it is extremely difficult.

Do you think the "paper thin ribbon" could have breaks in it which make partial contact some of the time? If it was the display itself why would the lines dissappear some of the time? My lines seem to come and go, suggesting that something moves. Are there any changes to the lines when you move the ribbon?

[malcolm e boo]

My lines come and go although there are two which are constantly there,

I also notice that the longer they stay on for the more lines appear.

[simdel1]

http://www.instructables.com/id/Repa...nctioning-LCD/

Looks a bit risky, but I might try it if my screen gets much worse.

[CMWI]

I've had the 'spidering' problem on 2 75s now, just appeared overnight on my diesel as though something had got in there!
1st Photo attached from V6 Connoisseur SE that shows the vertical line next to the 'spidering', 2nd shot from the diesel doesn't have any vertical fault lines just the squiggles.

[Batallo12]

what a pity... i've got 2 or 3 lines missing, it's all completely well-readable but knowing sooner or later will become more and more

edit: OMG, i had never seen the "spidering" before, looks really horrible! -_-

[marinabrian]

The mylar ribbon connecting the display lcd to the main pcb, goes brittle with age, causing minute fracturing in the conductors, and you end up with the classic "lines".
Replacement of the ribbon is nigh on impossible, due to it also housing the driver ic for the display.
Replacement of the IPK is the best course of action, it doesn't have to be the one for you car, you don't need T4, however the ability to desolder/resolder the ic 93s56 located on the main pcb which contains all the data pertinent to your car.
HTH
Brian

[Keith O]

I've had a problem with the same lines appearing, they do seem to go as the car is used more. To my mind it might have something to do with condensation or other moisture which is gently driven away by warmth only to return when the car is left overnight. I'd be very interested if there is a solution.

[pab]

Originally Posted by marinabrian

The mylar ribbon connecting the display lcd to the main pcb, goes brittle with age, causing minute fracturing in the conductors, and you end up with the classic "lines".
Replacement of the ribbon is nigh on impossible, due to it also housing the driver ic for the display.

Under close examination the whole of the display is impossible to remove because of how delicate the ribbon connector is,I suppose once this ribbon is creased the unit would be deemed useless.Once removed I was surprised that it only comprised of a screen..the whole thing works like a projector.

[HarryM1BYT]

Originally Posted by David Lawrence

Do you think the "paper thin ribbon" could have breaks in it which make partial contact some of the time? If it was the display itself why would the lines dissappear some of the time? My lines seem to come and go, suggesting that something moves. Are there any changes to the lines when you move the ribbon?

It was a scrap unit and no way to power it up or actually carry out any tests on it, so obviously no way to see if waggling the ribbon made any difference. It is quite possibly the ribbon failing, I have seen similar ribbons where moisture has somehow managed to get into it and damaged the ribbons tracks. I saw none of this damage on this particular one, but nor did I know whether this one was actually suffering any missing line issues.

Elseware, someone mention a driver IC actually in the ribbon cable. It looks like a silver square about 5x5 mm in the middle of the ribbon - I suppose that might also be a cause of the lines issue, maybe making poor contact to the ribbons tracks.

I would suggest that the only sensible way to do a waggle test on the ribbon, would be to cut an access hole into the top of the instrument panel case....

If you take the entire panel out, there is a 'sticky up' bit of the black plastic case at the top edge, as part of the main moulding. The 'sticky up' bit is where the ribbon cable is located. So it might be possible to (very carefully) cut this bit of plastic out, to get some access to the ribbon.

I certainly would advise against any attempt to open the case up, unless there is absolutely no other option and you happen to be a good keyhole surgeon. The panel is held together with screws, molded plastic lugs, you need to get the gauge needles off, the lower LCD display has a metal frame with spring lugs pulling it tight to the PCB against the conductive rubber contact strips - these latter lugs are inside and are very difficult to release without damage. It certainly doesn't seem to have been designed to ever being taken apart for repair and it is all very delicate.