HP25 calculator - UK Vintage Radio Repair and Restoration Discussion Forum

ppppenguin · 23rd Dec 2008, 2:36 pm

I've just been given an HP25 programmable calculator.

Does anyone know of a scan of the manual?

Unexpectedly for an HP some of the number keys have lost their nice positive action. Any thoughts on dismantling the keyboard and what to do about it.

The battery is undoubted shot. Looks like a pair of AA nicads in a plastic cradle that's been designed so that you can't extract them without surgery. Any thoughts on this and also cleaning the nasty furry chemical residues all over the contacts. I'm thinking of either a fibreglass or brass brush

peter_scott · 23rd Dec 2008, 8:10 pm

Hi Jeffrey,

Here's the Journal article http://www.hparchive.com/Journals/Lo...Resolution.pdf

I do have an applications program book for the HP25 but it's 160 pages long.
If you can give me some special areas of interest I can fire off parts of it.

I've never taken one apart although I did replace the NiCads in one a few back. It was just the application of brute force and a Stanley knife, followed
by a re-gluing on assembly

Peter

ppppenguin · 23rd Dec 2008, 8:19 pm

Peter, thanks for the link and the advice on replacing the nicads. At least they are ordinary AA cells, not some kind of special. My first calculator was a Texas SR50 which eventually got a homebrew replacement battery pack which sticks out and is held on with gaffer tape!

peter_scott · 23rd Dec 2008, 8:34 pm

Actually, I've found the Owner's Handbook too but it's 120 pages long.
Let me know what bits interest you.

P.

peter_scott · 23rd Dec 2008, 9:19 pm

http://fixunix.com/hewlett-packard/1...tery-pack.html

23rd Dec 2008, 2:36 pm	#1
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	HP25 calculator I've just been given an HP25 programmable calculator. Does anyone know of a scan of the manual? Unexpectedly for an HP some of the number keys have lost their nice positive action. Any thoughts on dismantling the keyboard and what to do about it. The battery is undoubted shot. Looks like a pair of AA nicads in a plastic cradle that's been designed so that you can't extract them without surgery. Any thoughts on this and also cleaning the nasty furry chemical residues all over the contacts. I'm thinking of either a fibreglass or brass brush

23rd Dec 2008, 8:10 pm	#2
peter_scott Dekatron Join Date: May 2003 Location: Edinburgh, UK. Posts: 3,274	Re: HP25 calculator Hi Jeffrey, Here's the Journal article http://www.hparchive.com/Journals/Lo...Resolution.pdf I do have an applications program book for the HP25 but it's 160 pages long. If you can give me some special areas of interest I can fire off parts of it. I've never taken one apart although I did replace the NiCads in one a few back. It was just the application of brute force and a Stanley knife, followed by a re-gluing on assembly Peter __________________ http://www.nostalgiatech.co.uk https://www.youtube.com/c/PeterScott/videos

23rd Dec 2008, 8:19 pm	#3
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: HP25 calculator Peter, thanks for the link and the advice on replacing the nicads. At least they are ordinary AA cells, not some kind of special. My first calculator was a Texas SR50 which eventually got a homebrew replacement battery pack which sticks out and is held on with gaffer tape!

23rd Dec 2008, 8:34 pm	#4
peter_scott Dekatron Join Date: May 2003 Location: Edinburgh, UK. Posts: 3,274	Re: HP25 calculator Actually, I've found the Owner's Handbook too but it's 120 pages long. Let me know what bits interest you. P. Attached Thumbnails __________________ http://www.nostalgiatech.co.uk https://www.youtube.com/c/PeterScott/videos

23rd Dec 2008, 9:19 pm	#5
peter_scott Dekatron Join Date: May 2003 Location: Edinburgh, UK. Posts: 3,274	Re: HP25 calculator http://fixunix.com/hewlett-packard/1...tery-pack.html __________________ http://www.nostalgiatech.co.uk https://www.youtube.com/c/PeterScott/videos