Sharp PC-1211, battery question

[Nigel (UK)]

Having replaced the display in my Sharp PC-1211 last year, I used the 675 hearing aid batteries mentioned above to power it. On returning to the machine after a gap of several months I found that it wouldn't switch on; opening it revealed quite a lot of white powder inside the machine from the batteries. The 675 batteries are zinc-air and they have a hole in them to admit oxygen; the powder seemed to have come from this hole! I don't think that these batteries are intended to have a long useful lifetime once the sticker is peeled away to let the air in! (Fortunately the white powder brushed away without doing any damage.)

Next, I tried using four LR44 cells: the machine worked, but the unlit pixels always showed as grey.

So, instead, I'm using three LR44 cells to power this four-cell machine. I've shorted out the fourth cell compartment (the one at the top) and everything seems to work perfectly. Of course, the total voltage is lower than it should be, and a low battery warning will be triggered once the cells have run down a little. But if I use three silver oxide cells (3 x 1.55V), which keep an almost constant voltage until they are nearly exhausted, everything should be fine.

Has anyone else tried this? Is it a bad / good idea?

Nigel (UK)