Sinclair ZX80 / ZX81 / Z88 Forums

I just got a mostly working Sinclair calculator.

I believe this is the obligatory way to prove functionality:


Marginally comic numbers aside (although very appropriate given the level of humour back when this was released) this does have a few issues:


One of the segments doesn’t light up (they should all be 8s). Not a massive issue given how much use this is going to get!

Also I have to get the batteries in exactly the right position in order for it to switch on. I have given the contacts a clean with IPA but suspect they need something stronger? They are heavily tarnished but look a bit fragile

Some photos:

Is this a Cambridge Type 2? Not really up on these - before my time! Just.

Very, very gently clean the surface of the cell contacts with a fibreglass cleaning pencil.

Then use contact cleaner.

Don't know enough to advise on the segment problem. If the display is multiplexed., it could be the LEDs themselves, otherwise the same segment on all digits would be affected.

Mark

Thanks Mark. I will give the fibreglass pencil a go.

Wow, this brings back memories. In 1977 i had a similarly sinister-looking black calculator with xylon display. it was a Litton and so rare there are no pictures of it

Had to look up fibreglass cleaning pencil. hadn't heard of that before

Also used to clean coins by some and the armatures of power tools.