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+--- Forum: Not quite HP Calculators - but related (/forum-8.html)
+--- Thread: HP-25 DIY with Z80 (/thread-14903.html)
Pages: 1 2
RE: HP-25 DIY with Z80 - eshazen - 09-02-2020 03:10 PM
Sorry for the long absence and not answering... challenging times.
Some people ask about keycaps. Search "Cherry MX relegendable" on e.g. Amazon.
Here is one seller, though they seem to be out of the 1x1 clear style right now.
The tops pop off and you just insert your own paper legend.
X-keys Keycap Cherry MX Compatible (Single, Purple, 10 Pack)
by P. I. Engineering
Learn more: https://www.amazon.com/dp/B00FZGETOM/ref=cm_sw_em_r_mt_dp_ww7tFbEBMZQ6N
RE: HP-25 DIY with Z80 - eshazen - 09-02-2020 03:20 PM
I needed a new one for my office, and for variety I decided to use VFD displays.
It has a new power supply PCB at the back to provide the 1.2V @ ~1A and 25V for the VFDs and handle power sequencing.
I used Microchip HV5812 drivers for the VFDs which was quite straightforward.
All docs updated on github: https://github.com/eshazen/retro-25
![[Image: vfd-top-800.jpg]](http://ohm.bu.edu/~hazen/HPCalc/retro/vfd-top-800.jpg)
RE: HP-25 DIY with Z80 - BobVA - 09-02-2020 08:10 PM
Nice! Thanks for the update!
RE: HP-25 DIY with Z80 - mpark - 10-11-2020 07:49 AM
Eric presented his calculators at the HPCC 2020 virtual conference. If you missed it, here's his presentation on youtube: https://youtu.be/Dise2HRakZ4?t=10213. Hopefully the timestamp works, but if not, skip to 2:50.
Great job, Eric!
RE: HP-25 DIY with Z80 - Eric Rechlin - 10-11-2020 05:39 PM
Direct link here to his talk:
https://www.youtube.com/watch?v=w87x0tetvFI