I recently came across this register, it was working but now needs a new back-up battery. The original one is of October 1978. There are no identifying marks apart from the date. It looks like a normal AA battery but that is where the similarities end. Inside the plastic cover of the battery there are three cells linked together and none of those have information on them. Is it a 1.2 v or a 3.6 v? I don't want to over volt the memory system and fry it or under volt so that it doesn't retain any information.

The register I have is made by Inokoshi, the model is 102 that also came as 104. Made in 1978 going by the original battery along with the images in the instruction booklet.

Please help me to fine the right battery.

Best wishes
Matt

i replied to this over the weekend - no idea where that post went.
they are one third AA sized nicads 90mAh i seem to remember.- you can safely replace them with nimh cells of a similar - or higher rating