TIny_Hacker wrote:
mushu wrote:
Is this ribbon connector also at fault for when there are a few "squiggly" clumps of pixels on the screen that are always black even when the calculator is off? I loaned it to my daughter and when she brought it back she said it just started doing that...I'm hoping she didn't drop it or something sharp poked the screen. The glass looks fine, its just got a clump of tiny lines that look like molecules or tiny trees in the winter (heh) in one spot always visible. I pulled all batteries (even the backup) and let it sit for a few days and the clump of pixels are still showing on the display without batteries. Any ideas on fixing this, or even troubleshooting?

I'd assume that this is a damaged LCD issue, and I don't think it can be fixed. I'm no expert, but this has happened to a lot of the LCDs of calculators that I've seen and there's not really anything you can do about it. I think most likely one of the pixels burst but that could be completely stupid on my part so don't listen to what I've said if it's all completely wrong Razz

Pretty much. Normally, the LCD has a few layers bonded together, sealing each other so everything stays where it should be. If there's a spot that comes unbonded or a tiny fracture opens in one layer, the liquid crystal leaks into the void or crack and deforms, making the dark blob. I've heard about "squeezing" the leaked blob towards one edge, but I've had no luck with this approach. It's particularly annoying, as it spreads, is difficult if not impossible to fix, and ruins many a good calculator.
I replaced the ribbon cable on a 83+ SE nearly a year ago; I've wanted to write up a blog post describing the typical symptoms and walking through the repair, but haven't. What I do have and can easily share right now though is a time-lapse video of the soldering:

The wire I used and general soldering job isn't particularly good, but it did work out in the end. If you're paying attention to connecting the two ends together, I had to attach one wire further up on the LCD board after I lifted the pad, so I had to remove soldermask elsewhere on that trace so I could tack the wire on.
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