FS: (eBay) Vintage HP 35 Scientific Calculator

[danielbriggs]

Not quite the latest and greatest tech!
But I know some people on here like calculators
So I'm selling an old HP 35 if anyone is interested in it.

Unfortunately it won't power on with the included PSU.

https://www.ebay.co.uk/itm/113127035187

I undid the back to have a look for any obvious signs, couldn't find much so put the back back on.
But check out that 1970's tech!


Will post worldwide at buyers cost.

Cheers,
Dan

[bd139]

Added to watch list

Repaired a few of these for people.

[retrolefty]

You should have little problem selling that as HP RPN calcs are very collectable and even as a parts donor it has value.

[glarsson]

Unfortunately it won't power on with the included PSU.

Isn't the HP 35 one of the calculators that are destroyed if the charger is connected without a working battery?

[bd139]

No it should be fine if you do that. I ran an HP35 without a battery for ages.

Usually one of the power supply caps goes short and pops a diode. There’s a little SMPS in the unit.

A lot of people think this is a beyond repair situation but a 1n4148 and a modern tant can be substituted in.

[danielbriggs]

Good to know bd139! 

[tggzzz]

Well, it works

All I did was check the brick's outputs are 4V and 50mA, and clean the on/off switch, and connect it.

I also used the Tek scope technique  for cleaning rotary gold finger switches; I used paper dipped in IPA to clean the hey switches.

[bd139]

Ah so you nabbed it

Enjoy. Nice bit of kit.

[tggzzz]

Ah so you nabbed it

Enjoy. Nice bit of kit.

Yup. Paid more than I wanted, of course. But you only live once

I should put on record that Mr Briggs was most obliging w.r.t. communications and cheap/easy hand delivery to a relative's house. I left a suitably gushing fleabay review

[danielbriggs]

Great stuff!

I’m glad it was so simple.