600D ROM support for both 24- and 48-character modes

[Klyball]

Apparently, the color doesn't actually work without an additional board (630). And I've never seen one. It's supposed to connect to J75, which is an empty DIP socket next to the character generator. (Schematics are on Mark's site.) The color RAM itself (a single 2114 - the same as on a C-64) is on the CPU board, but the circuitry to interpret it isn't. Weird. The ROM image I posted does clear the color RAM ($D400-$D7FF, low four bits) to white-on-black (which is $E) when it clears the screen, but I guess little purpose is really served by doing so.

I have blank 630 boards replicated from the original i have

[ronin47]

Apparently, the color doesn't actually work without an additional board (630). And I've never seen one. It's supposed to connect to J75, which is an empty DIP socket next to the character generator. (Schematics are on Mark's site.) The color RAM itself (a single 2114 - the same as on a C-64) is on the CPU board, but the circuitry to interpret it isn't. Weird. The ROM image I posted does clear the color RAM ($D400-$D7FF, low four bits) to white-on-black (which is $E) when it clears the screen, but I guess little purpose is really served by doing so.

I have blank 630 boards replicated from the original i have

Am I right in saying the 610 and 630 will work together?

[Klyball]

Yes they all work together. The 630 also connects
To the a15 600d only

[Mark]

Steve Gray has made a color RGBI interface for C1P see this thread: viewtopic.php?f=3&t=452 or his project page here: http://cbmsteve.ca/osi-600d-colour/index.html

(It's a LOT smaller than a 630 board!)

-Mark

[ronin47]

Steve Gray has made a color RGBI interface for C1P see this thread: viewtopic.php?f=3&t=452 or his project page here: http://cbmsteve.ca/osi-600d-colour/index.html

(It's a LOT smaller than a 630 board!)

-Mark

Oooh, thanks! I'll take a look at that.

[jbtech]

Glad to see it works!

To restore the original "D/C/W/M ?" reset prompt, change ROM locations (offsets from the first byte) $330 through $332 to $20 $3F $00. Do likewise to $730 through $732 if you want to hide the S (and undo the space/question mark swap) in 48-character mode as well.

Thanks bxdanny, I did replace the 3 bytes to restore the original startup prompt so my unit appears as original but still swaps to 48 column mode when the 'S' key is pressed at the prompt.

Before installing the replacement EPROM I cut the W8 link from A10 to pin 19 of the monitor ROM as per your instructions

cut.jpg (116.03 KiB) Viewed 185 times

and on the solder side added a wire from the ROM side of W8 to U72, pin 10 .

link.jpg (151.56 KiB) Viewed 185 times

A great enhancement to the board with minimal modification, thanks again!

Regards, John.

[Thomas]

Hi BXDanny, that seems to work great and the 48 column text looks much nicer I have to admit.

I hadn't planned to do any major mods to mine, mainly to keep it as close to the way my original OSI600 B was back in the day but this is so simple and utilises the other half of the SYN600 ROM space which was unused by the Superboard II previously.

I didn't realise the board would support 48 column mode without major hardware mods.

One tiny change I may make to the ROM file just for my own preference is to hide the /S text on the 24 column startup display, making it a hidden selection. Just for nostalgia sake - that D/C/W/M ? prompt must be burned into my own memory somewhere!

I imagine pressing S will still work even if the choice is not displayed, hopefully I can just replace the /S characters with ASCII spaces?

Thanks for coming up with that great soft-mod.

Regards, John

IMG_2185.JPG

Hi John,
you've mention, that your board is a OSI600 B.
For me, the IC's along the ROM sockets indicate a Rev D board. Could you please confirm.
Thanks Thomas

[jbtech]

Hi John,
you've mention, that your board is a OSI600 B.
For me, the IC's along the ROM sockets indicate a Rev D board. Could you please confirm.
Thanks Thomas

Hi Thomas,

I was referring to two different boards there, sorry if that text was ambiguous.

My original Superboard II which I purchased back in 1980 was I believe a Rev. B.

Sadly I no longer have that one and recently built up the Klyball 600 Rev. D reproduction PCB

The photo here is of the recently built Rev. D PCB.

Regards, John.

P.S. the background story and build of the reproduction unit can be read here if interested:

http://www.jbtech.linkpc.net/ohio.htm

[Thomas]

Thanks for the reply.
Nice photo of your old system with case and monitor.
I had a similar looking red monitor as well, actually a Hitachi TV F-54G-311.

Hitachi.jpg (12.13 KiB) Viewed 134 times

[jbtech]

Thanks for the reply.
Nice photo of your old system with case and monitor.
I had a similar looking red monitor as well, actually a Hitachi TV F-54G-311.
Hitachi.jpg

Yes, the perfect peripheral for a '70s computer!

There were plenty of portable B&W TVs around, in Australia (PAL) Colour TV only commenced in 1975.

I had 2 of those little orange TVs which I picked up faulty and both had the same fault so they were an easy fix.

Amazingly there is one identical model currently for sale, not too far away on eBay which is very tempting but the price has inflated a lot in 40+ years.

https://www.ebay.com.au/itm/11610534536 ... fresh=true

Regards, John