TI59 Battery Rebuild

I recently got one of these on ebay:

Unfortunately it had a US 3.3V ac adapter and no batteries in the battery holder. This meant I couldn't power it on.

I connected a 3 AA cell holder to the battery terminals and then the calculator powered up. Unfortunately the battery holder was way too big for the battery space. I got a 3 AAA holder and that fitted perfectly in the space in the case, but the original battery holder wouldn't fit. I didn't want to chop it up, so tried some rechargeable AAs in the original holder. This was tricky as there's little space in there and I couldn't solder to the batteries I had. So I ordered some tagged AA cells and fitted them into the original holder:

The holder then clips in (once I trimmed it a bit) and it is very neat.

I got a 240V to 120V ac adapter to step down our power to the level the 3.3V ac adapter can handle and I can now charge the batteries as well.

Unfortunately I haven't managed a successful read or write using the card reader yet...