I have a calculator from the 70's. It is a "scientific" type with a blue vacuum fluorescent display. A few of its button contacts are worn but it still works. It take it a few minutes to calculate the log of a number.

Originally Posted by zacha

Wow! Which one, the 1008 or the 1009? Or both?

Yes, it's 7.2v.

zacha:

I had worked on all the calculators they made as well as their computer
terminals and data logging equipment. I dont remember any of the
model numbers however, but i do remember they were BIG for just
a four banger calculator, and many of them had a paper tape roll.

If it says 7.2v then you should be able to try applying 7.2v to it to
see if you can get it working. Does it tell you the polarity too?
If it does, you can go by that, but if not, you might have to open
the case and take a look for hints as to what the polarity is,
and trace this to the connector.
Be aware that connecting the power BACKWARDS can permanently
damage the calculator, and i dont have any of the chips they used
to use because i think they were all proprietary, made by another
company and branded with their in-house part numbers.
If you cant figure it out, dont take a chance, instead take some good
close up pics and post them here and we can take a look.

audio:
Oh yeah, i had something like that way back then too. I loved that
display! Mine only had four functions i think, no sci stuff, but i still
loved it. I scoped it out one day with a scope that had an internal short
to the HV power supply and that zapped it...too bad...i only paid a
dollar for it too.