> -----Oorspronkelijk bericht----- > Van: cctech [mailto:cctech-boun...@classiccmp.org] Namens Paul Berger > Verzonden: zaterdag 10 december 2016 1:37 > Aan: General Discussion: On-Topic and Off-Topic Posts > Onderwerp: Re: Flex Disc options for the HP 9825 > > Some time ago there was a discussion about the elusive 98228A ROM that > supports both the 9885 and 9895 diskette drive units on a 9825T, well good > news! A fellow MoHPC member David Ramsey very kindly loaned me his, and > with a little careful reading of the service manual along with studying Tony > Duell's schematic I got a good idea of how it work, and observing the memory > bus using a logic analyzer confirmed how it worked. I was able to dump the > ROM using GPIO cards in a 9920 to simulate the memory bus, I actually went on > and dumped all the ROMs in the 9825T as well as a couple other I had. I have > successfully created a clone of the ROM and have even fit it into a a ROM shell. > I am going to try creating a PCB for it too, what I have now is just hand wired, > but it works. In the end the ROM module did not turn out to be very > complicated. I am just in the process of documenting my project and will > release a package soon with full documentation and most importantly the ROM > image. I plan to donate my package along with all of my ROM images to > hpmuseum.net. > > Paul.
Great work Paul. -Rik
