- missing pixels, rows or columns
few pictures caused by bad flex cable connection:
problematic flex cable:
(updated: ) take pictures before you disassemble it
To fix this we need a new cable, I sourced mine at aliexpres (but only 2pcs required). If it will be no longer available simply search for bmw e34 dashboard speedometer flex cable, check this search on aliexpress. You also need T-tip iron similar to this one. You can buy a combo of cable and iron, but unfortunerly these combos are most time 1cable and 1 iron and you need 2 cables.
When you will have required cable and iron
- while old cable is attached to LCD mark position of tracks on the LCD on both left and right side of LCD, use permanent marker which can be then removed with alcohol, but test if it can be removed or use transparent duct tape. Nex step is to take old flex of lcd and PCB.
- clean in with IPA. The cable need to by extended, to accommodate for more tracks required. I simply cut one side of cable to close as possible to track, but not damage it. Then I attache this part of the cable to the LCD with fully heated iron, take your time and align tracks of cable to pads on lcd. You will do not have another chance with this probably .... then count how much more traces you require and cut it from second cable and attache it.
The cable is longer then required, so updated next step is to assamblle it all together, then place cable on PCB side and mark where it needs to be cut and cut it with scissors.