HP8510C owners , OS will not boot

[shutchman2]

The 8510C has worked for years and all of a sudden, a week ago it stopped working. The self tests pass ( no error codes on the red 8-4-2-1 bit display on the front of 85101 ) and it gets to the "system initializing" message and does not go any further. After a while, the screen turns solid blue. (it thinks it's related to Microsoft?) The CR2477 battery on the I/O board was at 2.7V. I replaced it with CR2032, and it is now at 3.1V. I have another HP8510C that is working, which has OS HP8510C.06.30 Jul22 1991 OS.  I used the Service Functions menu Disc command 21 (initialize disc) and then command 20 to make a copy of it's OS. I tried loading this disk on the broken HP8510C using disk command 19. This did not fix the OS boot problem. I have heard that the EPROM sometimes goes bad over time. The EPROM is AM27C020-200DC with 85101-80133 Rev 3.04. I do not have any original OS disks for either 8510C. I do not know what the OS version was on the now broken 8510C. Does anyone have any advice for me on what I could try next? Thanks in advance. Does someone have the Jedec file and checksum for this version EPROM chip?

Regards, Hutch

[KE5FX]

It looks like the 3.04 EPROM image is available on ko4bb.com -- give that a try?

[shutchman2]

Thank You, I will give that a try. I have a Data-io Unisite.