Vintage calculator fixup questions

[zacha]

Hi folks,
I am hoping you will tolerate a friendly newbie who is trying to rehabilitate an old Singer calculator from the 70s, for a special gift to a special person.

It's this model **broken link removed**,

**broken link removed**

and I believe it's very similar to this model (under the Friden name) **broken link removed**.

**broken link removed**

Can anyone point me in the right direction on how to build a new power adapter? (Told you I was a newbie!) I have a very rudimentary knowledge of electronics from a summer I spent with a breadboard as a kid, but trying to find the parts I need on Mouser.com (see, I read the FAQ!) is pretty damn overwhelming, because I don't know the terminology.

The connection looks like this:

**broken link removed**

And it needs to be 7.2 volts, though I suppose that's the easy part.

Many thanks in advance for your responses.

 

[MrAl]

Hi,

Wow, i havent seen one of those in over 25 years!
I used to work for them and fixed their calculators way way back then.
We had a ton of them come back for service, piled up in the
hall way. I had to go through them one by one and find out what
chips went bad and replace them.
Sorry though, i dont remember much about them. Does it have a
voltage stamped on the side or no?

 

[zacha]

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

Yes, it's 7.2v.

 

[audioguru]

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.

 

[MrAl]

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.