I bought a TI-84 PSE Pocket off Ebay for not much, especially since it was advertised as being broken. The ad said only the top of the screen worked, but when I tried to turn it on I saw nothing. I opened it up and cleaned some battery corrosion and general grime in the buttons, but it didn't change anything. Given that this is probably a display issue, what are some things I should try in order to repair it? I have a multimeter and a soldering iron and all, so I'm fine with getting my hands dirty.
Have you been able to verify that it's actually powering on, for example by connecting it to a computer and taking a screenshot with TI-Connect? If there's corrosion, I'm concerned that (1) the mainboard isn't getting power from the batteries, which I've seen before, or (2) that the corrosion has degraded other important traces. Besides screenshots, I'd try putting a multimeter across power traces while the batteries are in (if you can) and make sure it's getting power.
KermMartian wrote:
Have you been able to verify that it's actually powering on, for example by connecting it to a computer and taking a screenshot with TI-Connect? If there's corrosion, I'm concerned that (1) the mainboard isn't getting power from the batteries, which I've seen before, or (2) that the corrosion has degraded other important traces. Besides screenshots, I'd try putting a multimeter across power traces while the batteries are in (if you can) and make sure it's getting power.

Good idea with TI-Connect. I plugged it in and was not able to get TI-Connect to detect it, so I’ll be breaking it open again today.
Good news! After some multimeting (what else do you do with a multimeter?) and a little bit of tin foil, I got the thing to boot. Just as advertised, the bottom half of the screen wouldn't show. I cranked the LCD contrast to 9 and covered the graphscreen with black pixels and came up with this:

What's Cemetech's diagnosis?
Extremely high confidence in degradation of the glue for the fine-pitched ribbon cable. That's unfortunate; I didn't realize any of the Pocket calculators were old enough to have the glue start drying out. Unfortunately, no one in the community has succeeded at finding a solution for that to date.
  
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