HP 82929A Programmable ROM Drawer Schematics ...


Hi There,

I know that folks have been looking for it in the past.

With help from other HP Series 80 fans I finally finished a
small reverse engineering project to obtain the complete
schematics for the HP 82929A Programmable ROM Drawer.

As you may know this module lets you add to a Series 80
personal computer images of expansion ROMs in a pair of

I've been always a big fan of the HP-85 and I recently
started some projects related to it.

Schematics for the HP 82929A and information about current
and future projects can be found at:

Thanks John Shadbolt and Everett Kaser for your kind help.


Edited: 29 Jan 2008, 9:54 a.m.



Nice work.



Hi Rik, John,

thanks for your comments and John many thanks again for your help.

While testing the clone version of the board I found a mistake
on the schematic I put together, the Chip Select lines for the
EEPROMs were permuted.

I updated the pdf file and the correct version is already on-line.

Also I fixed few things on the first version of a clone board
based with TTL and CMOS parts and now is under testing but
everything looks good.

The whole project is available here.

I'll start working on the microcontroller based version.

Stay tuned



Thanks Jorge,

Well done for a superb start on the prog ROM project, I'm looking forward to your next great idea.

Now, you still need a good name for your project (I'm thinking of Clonix41 here), so if any forum members would like to make some suggestions....


Possibly Related Threads…
Thread Author Replies Views Last Post
  who uses programmable calculators? John Ioannidis 24 6,335 06-18-2013, 04:11 PM
Last Post: Steve Simpkin
  HP85 Programmable ROM cardtridge 82929A-service ROM not working- inaki 2 1,856 04-25-2013, 08:08 AM
Last Post: inaki
  shelf life time of a ROM, EEPROM, EPROM vs Mask Rom Guido (Canada) 6 2,932 01-11-2013, 04:09 PM
Last Post: Thomas Falk
  Big ROM - 41 System DEMO ROM Ángel Martin 5 2,530 10-16-2012, 05:28 AM
Last Post: Ángel Martin
  HP41CV drains battery. Schematics? Harald 15 4,201 03-18-2012, 09:22 PM
Last Post: Luiz C. Vieira (Brazil)
  Seeking hp48 2MB and 4MB card schematics David Griffith 1 1,110 03-17-2012, 10:14 AM
Last Post: NateB
  TI Programmable 88 - What we missed... Joerg Woerner 22 5,489 03-08-2012, 12:08 AM
Last Post: David Ramsey
  Local variables in RPN programmable? David Hayden 19 4,607 10-28-2011, 03:57 AM
Last Post: Marcus von Cube, Germany
  Manual for vintage Russian MK-61 RPN programmable calculator? Cristian Arezzini 14 3,693 10-15-2011, 07:03 AM
Last Post: Cristian Arezzini
  Finding prime factors on a "non-programmable" calculator Don Shepherd 6 2,118 09-05-2011, 10:11 AM
Last Post: Allen

Forum Jump: