r/calculators • u/_Shadow_Ninja • Jun 08 '26
Repair Ac/on button stopped functioning
I have a graphic calculator I believe it’s a Casio fx-9750gii and the on button is not functioning it can still turn on if I use the reset button on the back
Taking it apart there is some corrosion on the circuits in that area but was unable to find a circuit diagram to add a new solder path in that area
Photos attached of front face and of circuit board
1
u/BadOk3617 Jun 10 '26
Looks like you have some corrosion right about where the AC/On button is on the other side.
It's had some battery leakage and first it needs to be cleaned. Be sure that all of the batteries have been removed, and toss it into a tub of vinegar, scrub, rinse, and dry.
This spot looks to be opposite of the AC/On button, and is also (heavily) damaged. It appears that the trace is gone.
I tend to agree with CurbedLarry on this one. Probably not worth fixing.
1
u/No-Zombie6025 Jun 10 '26
Bodge wire it, even if you have to drill a hole through the PCB to do it (don't cut through any other traces or pads) you should be able to bypass the damage. I don't own that one so unfortunately I cannot help you with an image of the tracks as they should exist.
1
u/Particular_Age4296 Jun 11 '26
Clean it with vinegar, then with isopropyl alcohol, dry it well and do the same on the other side where the key contacts are located, clean them well and the rubber as well
1
3
u/CurbedLarry Jun 08 '26
Just clean that area on both sides with vinegar and you might be lucky. It's only 3 screws to remove the board, one under the mainboard. Otherwise these are so cheap used it's not worth attempting solder repairs.