View Full Version : Reproduction SCELBI 8B Now Running SCELBAL

October 11th, 2014, 03:07 PM
This has been a very long time coming. I don't believe that any surviving original SCELBI 8B's are capable of running SCELBAL, mostly due to SRAM issues.

Heres a very poor quality video of it running.

Note that the versions of SCELBAL found on the net require 12K because they include all the available features and options. In order to run in a 8K system, the array features is going to have to stripped out of those versions.

More information on my reproduction SCELBI projects can be found on my webpages and blog.


Mike Willegal

October 12th, 2014, 12:24 AM
Nice work, Mr. Willegal!

I had to call my wife over to watch the .mp4 of you running my 99 bottles of beer program ... she gave me an "Attaboy", but I'm almost sure that she never really thought it was worth my time and effort spent writing and debugging it (and the dozen or so other versions) while not paying attention to her! :D


October 12th, 2014, 05:49 PM
There aren't too many SCELBAL applications out there, so I made use of your work. I think I need to port a couple of David Ahl's BASIC games in order to add some variety.

Thanks for taking the time to do it. :-)

Mike W.

Roland Huisman
October 14th, 2014, 02:06 PM
Hello Mike,

Nice work! My Mark 8 has also the HUGE amount of 12KB RAM memory.
(Story written in Dutch, but you may enjoy the pictures. Click on them to enlarge them)

In the past the two brothers who built it, ran also Scelbi Basic on it.
They made a tape interface in the machine and a boot loader in the 8702A EPROM.
And they had to put in the whole Scelbi Basic with their octal keyboard.
Days and days of programming, storing, checking... Must have been a lot of fun
when they actually got it running!

I can read and write into the memory of the machine again. But I'm not sure if
all of the 2102 memory chips are still in good working order.

I have also two original Scelbi books: "scelbi galaxy game for the 8008/8080"
and "Scelbi's first book of computer games for the 8008/8080".

I really love to see your Scelbi running the Scelbi basic. And also love to see
the Scelbi working itself! It must have been a time consuming project
finding all the components with the right date stamps etc...

Regards, Roland

October 16th, 2014, 05:53 AM
Unlike a number of other people, I focus on finding the right part numbers, but I don't worry too much about the date code.

In other words, I use parts that would work as replacement parts in an original SCELBI. The component mix on the SCELBI is surprisingly available. The hardest ICs are the 8008 and SRAM and they really aren't a problem at all, though the cost of all those SRAM ICs can add up.

Most of my effort has been focussed on reproducing the PCBs. I've been working on reproducting the SCELBI boards for several years now. I expect that completing the entire product line which includes an EPROM board and several I/O devices will take another year or two.

Other than the PCBs, the most difficult aspect is actually the connectors and hardware. Finding a decent price on the edge connectors and Amphenol type connectors can be a challenge. I still haven't entirely solved the chassis reproduction issue.

Mike W.

October 16th, 2014, 06:26 AM
...I still haven't entirely solved the chassis reproduction issue.

Good morning, Mike,

I am totally in awe at all of your hard work. I greatly enjoy stopping by your web site from time to time to observe the progress that you make, and I certainly enjoy your occasional posts here to highlight your accomplishments. Bravo to you!

A thought occurred to me when I read your statement about the chassis reproduction. I am a proud owner of the Altair Clone created by Mike Douglas (deramp5113, a member here). He worked with an outside vendor to recreate a very close facsimile Altair chassis for his machine. Might that be a possibility for you, too? Perhaps you have already looked into this, but I thought that it might be an idea to contact Mike and see what his experience was, and whether or not it might apply to you and your situation?

Like I said, just a thought...


October 16th, 2014, 12:28 PM
Hi Roland,

I'm just having fun whenever I find some spare time.

That Mark-8 of yours really shows how people took what they could get and made improvements where they could. I really like that control panel. I've thought of making something similar for the SCELBI, but there are too many other things already in my to-do queue.

The problem with the chassis fabrication is cost and with the SCELBI, when you start considering a couple of different I/O device and power supply enclosures, the cost really skyrockets. I'm looking into getting the necessary tools to make my own reproduction enclosures. If you can make your own, the cost becomes much more manageable.

Mike W.

October 18th, 2014, 02:40 AM

Last year, I went to the original manufacturer "BUD" who make the Scelbi 8h chassis and had the chassis reproduced. I ordered 10 of them. It was not cheap and it was a bit of a hassle mailing them around the world to people who needed them. I just passed the cost through and didn't make any money doing it (I might have even lost money), I just needed a chassis that was essentially the same as the original. They look great and you could have even used a left-over set of original Scelbi boards (if you could find one) and build a system that would be difficult if not impossible to tell the difference. This was one case where I did not "mark" a replica item that I had made to identify it figuring I know where they went and if in the future someone with an original Scelbi needs a chassis for repair, they could scavenge one of these since they were made by the original mfr.

My only regret was not having the pilot holes pre-drilled in the back to make it easier to punch out the IO ports. That was more of a convenience thing as it was a pain to drill the holes.

I'm not sure what I'll do for the 8B project. I may do an order again for more Bud chassis in the 8B spec. Right now I'm busy working on my 8H peripherals and don't want to start building a new computer for a bit.