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OSI reproduction boards: Who is interested?

D

dfnr2

Experienced Member
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Dec 6, 2011
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466
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Dallas, TX
Now that we have Gerbers from scans of several original OSI boards, we are able to produce some bare PCBs.

We already have some actual PCBs out there, including Klyball's 600 and 610 boards, Grant's data separator board, Klyball's 470Z disk interface with data separator and RAM/ROM, plus Glitch's universal memory board and 560Z board. I think these are all available now, or will be soon.

It looks like the cost will be on the order of $20-$25 per board if we get at least 10 PCBs in an order, not counting shipping. This is using the PCBcart online calculator for prototype boards. There may be better prices out there.


I would like to use this thread to express interest in the following boards:

502 (6502 CPU with 8K RAM and BASIC in ROM)
505 (6502 CPU with floppy interface and extra I/O; no RAM )
540B (color video board, 32 x 64)
580 8-slot backplane

These, together with the boards mentioned above, should be enough to create a full OSI system. For disk interfaces (if you don't have a 505 board) I would look into Grant's 470Z board. For memory, I'd look into Jonathan's new universal memory board before an older OSI board.

I am considering doing a scan of the 48K dynamic RAM board and the 24K static RAM board, but the 24K RAM requires its own power supply in C2/C4 systems. it's got 48 2114 chips drawing 70 to 100 mA each. The lower end of that range is the low power 2114L chips!

Use this thread, or the sister thread at the OSIWeb.org forum, to record your interest. If any board gets 10 interested folks, I'll pull the trigger. I'm counting myself as in for one of each board, so that makes 9 more hobbyists for any board.

Dave
 
The Universal RAM board is just about ready for production, I need to add the C2P mounting hole and a few pull-up resistors to allow partial population.

There are *plenty* of 560Z boards available, as well as full parts kits, including IM6100s.

Happy to do the board orders and kits, or just the kits if you're wanting to run the boards, Dave.
 
As someone who doesn't know anything about OSI systems, what would it take to get a fully functional system built up from scratch? One of the two CPU boards, the video board, a backplane, and a memory board if the CPU board has no memory? Would you recommend a CPU board with no memory in favor of having the FDC built in? So at least 3 or 4 bare boards, plus all of the components to populate them, plus some sort of keyboard, power supplies, floppy drives?

Seems like an interesting project, but I have no idea how much work and $ it would take to put a working system together.
 
I'd like to put my name down for a pair of 502 boards. Are these exact copies of the originals and therefore going to require a little extra work to use standard 2716 EPROMs?

Cheers,
Dave
 
Moonferret said:
I'd like to put my name down for a pair of 502 boards. Are these exact copies of the originals and therefore going to require a little extra work to use standard 2716 EPROMs?

Cheers,
Dave
Click to expand...

They are very close to the originals. Gerbers were prepared from calibrated scans of the original. That process replaced the original fonts with stroke fonts, and replicated polygons with numerous traces, resulting in slightly rounder edges. I imported the Gerbers into the Altium PCB program, recreated the polygons by tracing the outlines as closely as I could (to reduce the file size and processing time), and recreated the text to get closer to the original fonts. So, not exact.

Now that the files are in Altium PCB format, a future project will be to enter the schematics and link the netlists. Then modifications will be a snap.
 
glitch said:
The Universal RAM board is just about ready for production, I need to add the C2P mounting hole and a few pull-up resistors to allow partial population.

There are *plenty* of 560Z boards available, as well as full parts kits, including IM6100s.

Happy to do the board orders and kits, or just the kits if you're wanting to run the boards, Dave.
Click to expand...


It would be awesome if you handled the PCBs.
 
That would be fantastic. Can you post here and on the osiweb forum, and indicate what the trigger will be for ordering?

Thanks for taking this on!!
 
We also have gerbers for the 582 4-slot backplane, which my be of interest to anyone who would prefer a C4P style computer rather than a C8P big-box style.

You can see the list of available reproduction boards on the Github site.

Feel free to express interest in any other of the boards here as well.

Dave
 
gslick said:
As someone who doesn't know anything about OSI systems, what would it take to get a fully functional system built up from scratch? One of the two CPU boards, the video board, a backplane, and a memory board if the CPU board has no memory? Would you recommend a CPU board with no memory in favor of having the FDC built in? So at least 3 or 4 bare boards, plus all of the components to populate them, plus some sort of keyboard, power supplies, floppy drives?
Click to expand...
You're right on target. If you want a BASIC-in-ROM and cassette model, like a C4P, then a 4-slot backplane, a 502 ROM/cassette CPU, and a 540B video board would get you started, and you could upgrade later to a floppy system by adding a 470 floppy board and a RAM board, or Klyball's 470Z which has the floppy and RAM all together.

For a floppy system, the 505 CPU+floppy, a 540B video board, and a RAM board (from Glitch) would get you started. With the 505 board, you can add an A15 I/O connector board to get extra I/O. The A15 is also on Github, and if there is enough interest, I'm sure a run of those could be arranged.

Seems like an interesting project, but I have no idea how much work and $ it would take to put a working system together.
Click to expand...

These designs are really meant to be built up and hacked by hobbyists, so there are lots of common TTL chips, widely spaced. That means lots of soldering, so a good soldering iron and good eyes (or good glasses.) I like to solder with a head magnifier nowadays.

Each large 8x10 system board would be about $20 or so bare. I'm not sure how much parts would be but these boards have somewhere in the range of 10-30 TTL chips per board, and you'd probably want machined pin sockets, so parts could add up.
 
The boards end up being around $25 from the supplier I use, in qty. 25, which seems to be about what the community will support at the moment.

I'll get preorders up and going tomorrow -- been traveling for work all day today!
 
dfnr2 said:
We also have gerbers for the 582 4-slot backplane, which my be of interest to anyone who would prefer a C4P style computer rather than a C8P big-box style.
Click to expand...

I was planning on laying out a new version of this, as the spacing between the connectors is off enough to make boards slightly more difficult to insert. I've got a KiCad part with correct spacing defined for the Universal RAM board.

Here are the links to current active OSI preorders:

Reproduction OSI 502 CPU
Reproduction OSI 505 CPU
Reproduction OSI 580 Backplane
Reproduction OSI 540B Color Video
Glitchworks GW-OSI-RAM1 Universal RAM Board

The OSI 560Z reproduction boards are currently available, full parts kits too. All projects will be available as just the board, a full parts kit, or assembled + tested.
 
glitch said:
I was planning on laying out a new version of this, as the spacing between the connectors is off enough to make boards slightly more difficult to insert. I've got a KiCad part with correct spacing defined for the Universal RAM board.
Click to expand...

The 582 4-slot backplane on Github is different. It's from a scan of the PCB by Mile High Test. It should fit the same as the original, but it could never hurt to check out the Gerbers and make some measurements to ensure it's good. Since I have the scan imported to my PCB CAD software, it will actually be easier to fix any spacing errors than it was to do all the scan cleanups.
 
Oh, I'd gotten one of Grant's boards, I didn't know you had an original scanned. I'll check it out, and report back. As long as it's good to go (or it gets corrected) I'll add a preorder for it.

Thoughts on getting backplanes ran on heavier PC board material? The originals have a *lot* of flex if they're not mounted securely. My Challenger III uses a spacer behind the backplane to allow the solder side of the pins to press against the aluminum plate it mounts on.

Do you want to edit your original post and put the preorder links there, for anyone new to the thread?
 
glitch said:
Oh, I'd gotten one of Grant's boards, I didn't know you had an original scanned. I'll check it out, and report back. As long as it's good to go (or it gets corrected) I'll add a preorder for it.

Thoughts on getting backplanes ran on heavier PC board material? The originals have a *lot* of flex if they're not mounted securely. My Challenger III uses a spacer behind the backplane to allow the solder side of the pins to press against the aluminum plate it mounts on.

Do you want to edit your original post and put the preorder links there, for anyone new to the thread?
Click to expand...

Thicker backplanes would not be a bad idea.

I tried to modify the first post, but apparently the ability to edit expires eventually. I can onyl edit my more recent posts.
 
Boards are in, they look fine! I've sent emails out to everyone who preordered a 502 board. If you missed the preorder, there are plenty available for $25 USD per board.

I've only got one preorder for a parts kit, so I've contacted that individual directly and will probably choose to use money/time/resources on getting more of the reproduction boards fabricated than building up a 502 parts kit at this time.
 
Arriving late to this conversation. I have one of the prototype Universal RAM boards from Glitch and it is great.
Has there been any consideration given to reproducing the 541 hi-res graphics board based on the board layout\schematic published on the OSIWeb? I suppose a related question is "does anyone have the version of OS65D that could address and make use of 541?"
 
Ran across this thread looking for information about floppy data separators. I got a C4PMF off eBay; swapped out the memory for a glitchworks 48K; replaced two backplane connectors and… it works! Almost… :(
After some hair pulling I determined that the 5.25” floppy (MPI B-51/52) wasn’t returning any data. I’ve got tons of old PC 5.25 floppy drives laying around but… they don’t have data separators. Plus I’d also like to get a Gotek floppy drive emulator working. Anyway… that’s what lead me up to this thread. The first post mentions two separators but google searches didn’t find ether of those. I did find the SMC FDC9216B floppy data separator on eBay for ≈$7 but haven’t been able to get it to work (with 125 kHz x4 ==> 500 kHz clock).
Anyone know where I can get a floppy data separator for OSI 505B CPU?
 
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