I've just aquired a Melcor SC-635 calculator that's missing its battery pack. Does anyone know what voltage the original pack would have been? The keyboard has a nice colour scheme now that I've removed a few decades of cigarette smoke residue.

Hi Nick.

Have you seen this page:

Tony's Taschenrechner-Sammlung Calculator-Collection

Here's the link to the Melcor SC-635 from his site

Melcor SC-635

I hope this helps

Edited: 26 May 2012, 9:21 p.m.

Thanks for the link. I found it earlier but saw that he only refers to an external 9 volt charger and didn't open up the calculator to see what kind of battery pack it had.
I suspect the pack voltage was much lower than 9 volts. I've run the calculator on 3 volts and it works after a fashion but keeps insisting that x/y = x^2. Perhaps the corrosion I discovered within has rotted its electronic brain.

I thought the link was worth a try. Hope you find a fully functioning one.

Edited: 27 May 2012, 12:26 a.m.

Actually I don't mind that it gives wrong results. I just like the fact that it was made in the USA back when there was a thriving calculator industry.
Besides, what do a few incorrect answers really matter if you're designing nuclear power plants or highway bridges...