I need help with a wierd IBM 701c screen problem

[MadcatSE]

Hello,
I want to apologize for my English beforehand, and want to ask for help.

I have recently acquired an IBM 701c in a rather average condition. The person who sold it told me that some time ago he started to get the CMOS battery and RAM errors, and he gave the laptop to repair to a "recommended" repairman. Unfortunately the repairman turned out to be an alcoholic (such is life in wonderful Russia ). He disassembled the laptop, changed the small 1.2nicd battery for a 3v lithium one ( ), didn't even find a CMOS battery on the bottom board, assembled it again and returned it not only with the same CMOS and RAM problems, but with a new one: now the screen image is constantly scrolling down. Here is the video of the problem:

https://youtu.be/jPxX778tMJI

The laptop still manages to boot into Windows 95, so I guess the motherboard SHOULD be ok, right?
At first I thought that it may be the problem with the flex cable of with careless assemble. But when I disassembled it I found that the flex cable seems OK. No matter how much I push, pull or squeeze it the picture problem doesn't go away. The connectors for it also seem ok. And the connector to the display itself looks fine and sits tight. So now I am kinda lost. I don't have port replicator for it, so I can't test the external VGA connector. Nor do I have a separate machine for testing the parts. Do anyone have an idea what could cause this problem: the screen, flex cable, bottom motherboard or maybe even the top motherboard (I still don't like that he used 3v non-rechargeable battery for a replacement of 1.2v rechargeable one)?

[RealBlackStuff]

Welcome to the Forum.
Remove that 3V Lithium battery and try to run without it.
Also reseat the LCD cable at both ends (requires a fair bit of taking the 701c apart).

[MadcatSE]

Already done that, the battery fell apart during disassembly (it even leaked, but still holds 2.2v). The laptop now is completely disassembled for ease of inspection. Also removed flex cable from both sides and reinstalled - nothing, still the same problem.
Or did you mean CMOS battery? I didn't de-solder it yet, could it help? I don't see how could it help...
Update: took the CMOS battery out, didn't help (as I expected).

[MadcatSE]

Well-well-well! I decided to take a shot in the dark and ordered a new screen from aliexpress. The screen is Sharp LQ10D031, and they had one for about 90 USD. It took 10 days to arrive and - amazingly! - it worked!
https://imgur.com/IyJtW7E
It hurts that I have to wait till other parts arrive before assembling it, but it's nice to know that it's no longer an "IF" situation for me. ^_^

[MadcatSE]

Several months later my machine is *almost* done. All that is left is to rebuild the battery. I already managed to do that in September, by opening up a dead one, changing the elements inside and then gluing it together, and it worked for a whole day! But one of the battery pins on the motherboard had broke and shorted the IC pins on the battery itself, and the battery went silent. It powered the laptop until it had charge, but the laptop reported "no battery" status and didn't charge it. So I had to buy another one and NOW I will be really careful: I am going to dump the ROM from DS2434 inside, so if it dies again I could always flash another DS2434 and make the battery like new again.

Anyway, here is a little video of my machine in action
https://youtu.be/AHX7RdPyV5M