Hi there!
I am the one who does all that calc modding in my grade. Today, I got a patient that will need a full PCB removal, because the owner spilled a drink (I think it was coke) over the calc. Normally, the rubber mat would prevent PCB contact, but it was also over the display, and it was certain some come had leaked into the calc. Batteries were removed instantly to avoid more damage, but coke can (and will, if it isn't removed) ruin PCBs, thanks to sugar, and phosphoric acid. So this patient needs its PCB removed, which the dad of the owner already did ಠ﹏ಠ. What is your preferable way of reattaching that?

I would cut off those plastic things (which was done), and then use some strong 2-part epoxy when reattaching. I suppose I could also use screws, but I don't have the right size. What about friction-stir-welding with ABS printer filament (put a short piece of filament in a dremel and build up a bead)? That should enable me to build up a new plastic part.

So what do you suggest?

A very good description but did you have any photos?

Sometimes you can clean a PCB with iso alcohol and replace any shorted components for liquid damage.

I would hit that thing with alcohol immediately. Alcohol and q-tip should be able to get rid of any coke residue. As far as your screen goes, as long as none seeped into the actual lcd you should be good to clean that with alcohol too. Alcohol will not short anything electrical.

Reattaching the pcb, you don't have the screws that it was held in with before? Definitely would strongly advise against cutting any case plastic.

Well, as soon as I got that I wiped it with some deionised water and isopropyl. The LCD itself is fine, but the father cut those squeezed-out plastic bits that held the PCB into place. My calculator does have the same method of attaching the PCB to the front of the calc (well, it still is help into place with the screws that hold the whole calc together, but as I said, the plastic things that held the PCB in place were cut).

I'd rather avoid epoxy, as it is messy and pretty irreversible. I'm thinking about the friction-stir-welding, but the only filaments I have are PLA and PLA+ (PLA with some ABS). What do you think, should I give it a try?

Pictures would be really helpful. I don't advise any permanent solution to holding a pcb in a calculator. Screws should be enough for a TI-84

Edit: I've been informed that some TI-84's don't have screws. I'm not really sure here the best way to get it back in in that case.

Not enough of you take apart TI-84 Plus CE calculators to see what's inside. 🙃

From https://www.cemetech.net/tools/ti84pce:


Note the heat and/or pressure-stamped plastic "screws". One reasonable replacement could be small screws with plastic or nylon washers.

OK so you're just looking to reattach the boards + LCD due to case dmg - and will test if it works from there?

Some photos of the cut tabs would be good as well and great pics from Kerm so you can see how it's meant to look .

It actually is a TI 84+ (that old brick that one can overclock by replacing resistors). But yeah, it's about those pressure-stamped things. Those were cut off flush with the PCB by the father.

The calc works, I already checked that. As previously stated, the owner immediately removed all batteries, and wrapped it in paper towel (I'm a pupil, 17 years old, and as we have to wash our hands after every lesson, we have loads of grey paper towels).

The board itself also had no damage visible to the naked eye with optivisors, so the primary concern is getting the board mounted.

Has anyone used anything else than screws before? Because I don't have the right screws, and I don't really wanna buy 100 or so screws, just so I can use four or six to reattach a PCB, with the rest getting lost.

I will post pictures tomorrow, but for today, I'm gonna call it quits, and go to sleep.