Most worn out HP65 ever


I have bought a fairly cheap HP65 on ebay recently. And it turned out to be the most worn out machine I have ever seen. Unfortunately I didn't take pictures before I started repairing it.
Somebody had burnt the display with a cigarette, the case was held togather by tape and it was really dirty. Most of the metal "click" strips (how do you call those?) on the keyboard had broken.
So I replaced the burnt display by one off an old and broken 45 which I made to fit, replaced the broken parts of the keybord with ones from the same 45 and cleaned everything. I then did the card reader repair. And I even get it to work occasionaly. But even the card reader has seen that much use, that the brushes on the Motor have worn out and it often will not start. Has anyone ever attempted to fix that? I suspect even if I manage to open the motor, I wont't be able to replace the brushes. The calculator won't become a beauty anyway, but at least it fully works now - apart from the card reader, and that is bugging me :)


Cigarettes can't be good for anybody (even a calculator). Sorry, couldn't resist. Besides, in all the application programs I've seen for any programmable calculator (even a TI-59 or SR-52), I've never seen a 'Cigrarette Smoker' program. So, I don't think you can teach a calculator to smoke.

Edited: 2 May 2012, 5:18 p.m.


Over the years i have seen many people teach electronic devices to "smoke". However this usually causes a fatal malfunction. That's a question i used to always ask pilots and engineers "did you let the smoke out"?


Magic Smoke - actually, that is how electronic devices work.
And the proof is, they stop working when you let the magic smoke out :)


harald, if the brushes are defunkt, the motor will not start in any case. try to clean all card-activated contacts with isopropyl and test it again.


I have connected the motor directly to the battery. It will start as soon as I turn it by hand a little bit. When measured with an Ohm meter, it will sometimes show several kOhms and sometimes 2.5 Ohms.

It's definately not the contacts that have a problem.



You have mail.



No I don't. Something must have gone wrong. Try "h dot pott at gmx dot net" or "harald dot pott at gmx dot de".


Possibly Related Threads…
Thread Author Replies Views Last Post
  HP65 Prices - have I missed someting? Harald 9 3,148 05-17-2013, 06:54 PM
Last Post: ClausB
  Cheap rare HP35 and HP65 report Waon Shinyoe (China) 4 1,939 02-20-2013, 08:47 AM
Last Post: Frank Boehm (Germany)
  Restoring an HP65 (trying to .... few pics) Alberto Fenini 31 9,464 06-29-2012, 10:55 AM
Last Post: Peter HOFMANN
  HP67 motor in HP65 card reader - too slow Harald 4 2,076 05-21-2012, 06:52 PM
Last Post: Dave Shaffer (Arizona)
  HP65 program cards compatibility aurelio 2 1,298 05-04-2012, 04:43 AM
Last Post: aurelio
  HP65 related: I know it belongs in the adds, but I need advice. Luiz C. Vieira (Brazil) 2 1,284 04-07-2012, 07:31 AM
Last Post: Luiz C. Vieira (Brazil)
  HP65 vs HP67 card reader Alberto Fenini 2 1,329 04-17-2011, 05:09 PM
Last Post: Alberto Fenini
  HP65 in Nonpareil Harald 4 1,608 01-28-2011, 02:05 PM
Last Post: Harald
  HP65 (card reader) magnetic head Alberto Fenini 0 723 01-10-2011, 12:02 PM
Last Post: Alberto Fenini
  Restoring a card reader from an HP65 Alberto Fenini 1 985 11-26-2010, 01:50 PM
Last Post: aj04062

Forum Jump: