68766 8k eprom in the 600 Rev D

Post Reply
waltermixxx
Posts: 118
Joined: Sun Feb 03, 2019 10:31 pm

68766 8k eprom in the 600 Rev D

Post by waltermixxx » Sun Jun 16, 2019 1:37 pm

Success, last night Josh and I put the finishing touches on his 600D.
We did the 9600 baud mod, fixed the colour ram issue, brought TX out to pin 2 on J3,
And just for fun, we setup the 8k uk101 68766 eprom in U9, and cut/jumpered the board to us it. So now all 4 eprom sockets are selectable (bank selectable?) depending on what you put in the 55296 “register”. It controls BK0 and BK1.

Rom socket defaults to U9.

I modded my board to follow suit. I will help Steve’s with his, so he can, yet again rewrite his SJGMON initial menu to select which rom you want to start with. (That’s the theory, anyway.).

So a fun OSI 600 night for sure.

Two small cuts on the solder side of the board to isolate he 74LS138 A and B inputs from the rest of the OSI.
2A62E6CB-28D2-4795-8A3F-D9CFD7A4004C.jpeg
2A62E6CB-28D2-4795-8A3F-D9CFD7A4004C.jpeg (686.07 KiB) Viewed 855 times

Address AII and Adress A12 need to be hooked up to the eprom, pins 18 and 21,
and disconnected from +5 and Gnd. Cut the jumpers and connect to the address lines.
4D9CE77B-4C4F-4252-A776-49B0CAF75F1F.jpeg
4D9CE77B-4C4F-4252-A776-49B0CAF75F1F.jpeg (577.2 KiB) Viewed 855 times
BK0 and BK1 need to be hooked up to the LS138 A and B input to select which eprom.
6EC4DDB6-4CD6-48D5-A431-B78C9C159DAB.jpeg
6EC4DDB6-4CD6-48D5-A431-B78C9C159DAB.jpeg (903.47 KiB) Viewed 855 times
22CF294D-D2E9-45E9-84DF-73A75CE267AD.jpeg
22CF294D-D2E9-45E9-84DF-73A75CE267AD.jpeg (633.11 KiB) Viewed 853 times
Last edited by waltermixxx on Tue Jun 18, 2019 12:33 am, edited 4 times in total.
Turning into quite an OSI Junkie (HTFDTH?) Superboard II REV B-40K, 9600b, HC-05 Bluetooth, Superboard II Rev D, C4P rebuild- 502, 542c, 540B. :)

Steve Gray
Posts: 283
Joined: Mon Oct 06, 2008 1:54 pm
Location: Markham, Ontario, Canada
Contact:

Re: 68766 8k eprom in the 600 Rev D

Post by Steve Gray » Sun Jun 16, 2019 2:12 pm

Very nice!

At some point could you write up a little text file detailing the mods?

Steve
C4P working, C1P working. 600D Replica working, C4P+D&N floppy not working. 505 board, 610 board, Mittendorf board, TOSIE hacker board need testing, PicoDOS disk untested.

waltermixxx
Posts: 118
Joined: Sun Feb 03, 2019 10:31 pm

Re: 68766 8k eprom in the 600 Rev D

Post by waltermixxx » Sun Jun 16, 2019 3:27 pm

Yup it was my intention to do just that, as soon as I had a chance.
I would most likely edit the first post with the details, seeing as the pics are already there. :)

:)
Turning into quite an OSI Junkie (HTFDTH?) Superboard II REV B-40K, 9600b, HC-05 Bluetooth, Superboard II Rev D, C4P rebuild- 502, 542c, 540B. :)

Post Reply