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View Full Version : Mits Altair 88-2SIO Serial Input/Output Board for Sale or Reproduction?



stillwell
September 27th, 2015, 10:38 AM
I'm in the process of restoring two Altair 8800's :
S/N: 221045A
S/N: 223959K

Both were not working when I got them... most of the work needed was replacing bad logic chips on the front panel and fixing broken traces.

They are finally both working, but neither have a serial card. I would really like to get my hands on an MITS 88-2SIO Serial Input/Output S100 board, but only seems like that will happen if I buy another Altair with one already in it... Does any one have one they would be willing to sell. If I don't get my hands on one soon I will likely CAD up a replica 88-2SIO pcb and source all the chips..

I know Grant Stockly @ altairkit.com was testing an 88-2SIO reproduction PCB back in 2007 but I haven't been able to get ahold of him... Would really like to get my hands on his KiCad PCB drawings...

Here are my two Altair's and my newly restored ADM-3 Terminal:
26879

deramp5113
September 27th, 2015, 01:38 PM
I emailed Grant in the Spring and offered to do a turn-key run of his 88-2SIO boards for him. I told him I'd do all the work and front all the money and send him royalty checks if he wanted to send me the artwork. He got back to me and indicated he was just about ready to be back in business with his kits. Unfortunately, despite a reminder email or two, I haven't heard from him since.

There are a few other serial boards that can be strapped to use the same status bits for transmit and receive as the 2SIO uses. This is enough to keep all original Altair software happy, but won't work with software that tries to use the RTS/CTS or interrupt features of the 6850 UART. For example, look for the Solid State Music serial board. They come across eBay fairly often.

Mike

billdeg
September 27th, 2015, 02:45 PM
I could be convinced to put one up on Ebay..

stillwell
September 27th, 2015, 03:47 PM
Thanks deramp5113 for your thoughts, I'll keep my eyes out for the Solid State Music board.

billdeg, You have a buyer if you do! And since I need two I will likely use it to create a PCB from it for the Altair community!

I could be convinced to put one up on Ebay..

billdeg
September 27th, 2015, 03:59 PM
I will post one tomorrow. I need to look through and see what I have. It would be 1976 version, not 1975 but functionally the same.

stillwell
September 27th, 2015, 04:14 PM
Awesome! That is perfect!

tkc8800
September 27th, 2015, 04:24 PM
Good work on getting the Altairs working. I hear you about the serial card. I went through the same thing a few years back when I got my Altair without a serial card. It took me two years to get a working serial card. As Mike says above the best option if you can't find a MITS 88-2SIO is the Solid State Music IO4. I have a guide on my website that covers the configuration for the Altair in detail:

http://tkc8800.com/page/Configuring-SSMIO4-for-use-in-an-Altair-8800

stillwell
September 27th, 2015, 04:36 PM
Thanks tkc8800! I spent quite a bit of time on your site over the last few weeks while debugging issues with my 8800's. Thanks for that. If I get my hands on one of those Solid State Music IO4's I will use your configuration.

leiy
September 27th, 2015, 06:09 PM
Thanks tkc8800! I spent quite a bit of time on your site over the last few weeks while debugging issues with my 8800's. Thanks for that. If I get my hands on one of those Solid State Music IO4's I will use your configuration.

I have a SOLID STAT MUSIC IO4 board and other misc BD in collection. I will upload them on ebay tonight with BIN. Good luck.

stillwell
September 27th, 2015, 06:49 PM
Thanks leiy, I will watch for your listing!

leiy
September 28th, 2015, 06:41 AM
Thanks leiy, I will watch for your listing!

Hi, I have uploaded SSM IO4

You can view it here: http://www.ebay.com/itm/-/191703100408?

I have already modified the board as a MITS 88-2 SIO according to tkc8800.com, and tested on Heathkit H19 terminal. But in my ADM-3A terminal, some key response error character on screen, I don't know what cause the the error.

stillwell
September 28th, 2015, 06:48 AM
thanks leiy, purchased!

leiy
September 28th, 2015, 06:52 AM
Ok, Thank you, I see. There also has one cable, and SSM IO-4 manual. I will ship out with the board.

leiy
September 28th, 2015, 07:04 AM
Please let me know whether It can work smooth with your ADM 3A terminal after you receive the board.

Thank you.

tkc8800
September 28th, 2015, 03:56 PM
Thanks tkc8800! I spent quite a bit of time on your site over the last few weeks while debugging issues with my 8800's. Thanks for that. If I get my hands on one of those Solid State Music IO4's I will use your configuration.

Glad you found that info useful. I've got lots more content to put up on that site, it's motivating to know that people are reading it.

stillwell
September 28th, 2015, 08:35 PM
Were you able to find a 88-2SIO in your collection?


I will post one tomorrow. I need to look through and see what I have. It would be 1976 version, not 1975 but functionally the same.