- missing pixels, rows or columns
few pictures caused by bad flex cable connection:
problematic flex cable:
To fix this we need new cable, I sourced mine at aliexpres (2pcs required), but unfortunately item is no longer available, but similar are still 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 combo of cable and iron, but unfortunerly these combos are most time 1cable and 1 iron.
When you will have required cable and iron, take old flex of lcd and PCB. Clean in with IPA. 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 cable to 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.
Same goes for other side where is cable attached to PCB.
When you done it all, put it all together. Cable is little longer then it is required, so when assembled, it need to by gently pushed between PCB and white plastic holder of LCD. All done, check if it is working corretly, if not then try to attached it again in place where are missing pixels.
When I'm going to fix my second radio I try to cut cable down to exact height to avoid need for this kind of bends: