HP Forums

Full Version: 9810 restoration - my report
You're currently viewing a stripped down version of our content. View the full version with proper formatting.

...for those of you who remember the discussion about my dead 9810 in late december last year, I am glad to report that the machine now works again, at least partially. There is still some work to do on the printer and tape drive units, as well as on the power supply, but the calculator itself works flawlessly. I wrote a report on the repair hoping that it might be helpful to revive other 9810s:

9810 repair job

It's a fascinating machine, and I learned a lot about its architecture. Long live the 9810!


Congratulations, very nice page.

I also checked your HP 97 repair page, but since my German is prety weak, I didn't make much out of it.

How about translating that one as well?


When you want to sort out the printer or card reader, feel free to
contact me. I've taken both sections _totally_ apart, and can explain how they should work and how to repair them.

Thank you Tony. I will soon replace the faulty 74107 in the printer, and frankly expect it to work right after that - the print head looks like new, as does the motor.
The card reader however seems to require more work. I think I'll make it my christmas holiday project.

Hi Marias,

(Guten Tag!)

Had a look at your 9810 page; really cool!

I am wondering if you also have a failed driver transistor
on the output side of the 74107 motor "state machine" logic?

Just a thought.

Kind regards from Down Under!

Don W

that's quite likely, but these don't worry me, as I got plenty of transistors in my spare parts box. As soon as I found out that the 107 FF was dead, I did not bother to look any further. Maybe I'm in for a surprise when I replace the 107 - I'll keep reporting. Thank you for your suggestion!