Calculator uses two LR44 (alkaline) cells. I replaced them with two SR44 (silver oxide) cells instead to prolong cells/calculator life.
Problem is the calculator will no longer switch on using its power on button!!?? Pushing the calculator reset button (at the back) switches the calculator on OK! I can make adjustments to settings and do calculations, and I can also switch the calculator off. But the calculator will no longer switch on via its power on button!?
The calculator was working fine (via its power on button) previously just prior to the LR44 cells dying. I looked at the power on button "contact" and its corresponding circuit etching on the calculator PCB, but there was no sign of any damage, dirt, dust etc!? I cleaned the power on button contact and also its PCB etching anyway just to be certain (using diluted white vinegar), but the power on button still doesn't work!?
This is peculiar! Maybe this failure to switch on (via power on button) is intentional (by the calculator manufacturer)after cells have died so that one has to buy another calculator!? The reason I say this is, I had an electronic device something like a calculator which was used to login to a banks website and to authorize transactions. That device had to be fully replaced once its battery/cell died, and the device locked out after battery/cell died. Replacing that device battery/cell wouldn't work as the device was permanently locked out!
Anyone else have similar issues with a calculator not working (properly) after replacing batteries/cells??
Have you tried to rotate the power on button 180 degrees? Wear from daily use is often asymmetrical. Buttons that directly contact the etchings on the PCB get more or less ‘wore in’. In the end they only make contact “in the original position”.
Actually the "button contact" is part of a large rubber pad which covers the entire PCB. For each plastic calculator button (which is separate from the rubber pad) there appears to be a corresponding black carbon(?) dot or small button top under the rubber pad which actually makes contact with the corresponding etching on the PCB.
In this case I don't see how rotating the plastic power on button would help as there didn't appear to be any obvious issue (wear signs or damage) with its corresponding black carbon dot on the rubber pad. As mentioned before, the power on button seemed to work fine until the calculator original LR44 cells died.
So it is still a mystery as to why the power on button doesn't switch the calculator on after replacing the cells!?
Looked through the links, but I don't think the power on button (dot) is/was faulty.
The power on button was working immediately prior to battery/cell replacement. After new cells installed the power on button failed to work. After checking for any obvious signs of damage to and/or debris on the power on button dot (and its associated PCB etching), it is strongly suspected that the calculator has intentionally been made not to work by the manufacturer after the original battery cells die.
In other words the calculator was designed with "planned obsolescence" in mind!
The calculator has since been thrown out! I won't be buying that brand of calculator again!