The Heathkit H8 was one of the first computer I ever got to play with, started a love affair. I'm old now, but it was right at the front. My Mom's boss sold minicomputers, and let her bring it home from work for a couple months for me to see what computing was all about, as he wasn't using it at the time. Good times.
@@smbakeryt 🤣 That's certainly true! One thing I'm already most of the way through collecting parts for... is a replica Mark-8 personal minicomputer (I think it was called?), so I'll get plenty of 8008 experience with that. Your board uses modern components for more features in fewer chips, which is quite interesting, while the Mark-8 will be more "period accurate" (but with much, much, much less RAM, etc.).
Looks like a computer I built back in the days. I used a hardware multiplexed display with the same driver IC you used , the reason back then was that that chip in a ceramic package was very expensive. The scan was using a 7489 16x4 ram.
Seeing the H-9 brings back memories when I worked for Heathkit. I wish I still had the original plans, because I built a kit with 2 IC's that converted the H-9 from 12-lines to 24 lines on the screen. Maybe someone out their will have that kit conversion and respond to Scott about the kit.
Several folks at SEBHC have talked about this modification, and at least one person has a terminal with the modification installed. What we've seen so far I think is more complex than just a couple of ICs -- the pictures I saw looked like a fair bit of rework. The other popular modification was to add lower-case support and I think that required two chips (one of them being a second character ROM)
@@smbakeryt - My mod just had 2 IC's on a PC Board I created, and required 3 cuts on the main board, and then wires added to my, (very small board) that was just tucked away inside the case. This was done in 1977 or 1978, not sure, it's been so long. Heathkit put out a small news letter back then for a short period of time which I contributed to. I also setup the first Computer Club at store #4 in La Mesa, CA.
I wonder, could the weird bus architecture where when writing to an I/O port the data ends up on the address bus also be the reason why the Z80 has I/O instructions that put the I/O address on the lower half of the 16-bit address bus and the data on the higher half of the address bus and that this was done for some sort of backwards compatibility with its Intel counter-parts?
Brilliant project. Any chance of a rev with easier to source display drivers might be in the works? In recent years I have built micro controlled versions of the DEC PDP 8 and 11/40 as well as the IMSAI, Altair and Kenback . Maybe someone can come with a case similar to the original H8 and have a kit for another outstanding early 8-bit box. Hint, Chris Davis at Ad Water and Stir might be the guy to work out the enclosure,; his Altair box is outstanding. I still have my H8 built in 1977 and several others I picked up over the years. I absolutely love all the work and support you have provided for the H8 !!!!!!!!!!!!!!!
I do have a variant that uses TIL311, but they are not necessarily easier to source. Most other options for driving the display would require dropping resistors (DM9368 is really nice in that no dropping resistors are needed) and this blows up the component density on the board. Another option that has been proposed would be to use an FPGA or an Atmega as a slave to multiplex the displays but the disadvantage of this is that you're adding very modern components to what is supposed to be a vintage project.
It happens far too often where i find a great chip to run a 7 segment display. Just to find out it’s impossible to buy. Why is that!?! There are some great 7 segment drivers that were made that are just lost to time.
Eh.... those TIL311 clones from the UK are $3 if you buy 100.... ask me how i know, lol... My 130 were $3.40/ea with tax and shipping 8008 and it runs forth? Damn... i low key want one...
This is a good point. He’s got a team of 80’s engineers working round the clock on this stuff. Has to. It’s just not possible for one person to produce computers like this.
The key is re-use. Once you build a library of useful patterns and snippets of schematic, it's easy to throw together a new board in a short amount of time.
The Heathkit H8 was one of the first computer I ever got to play with, started a love affair. I'm old now, but it was right at the front. My Mom's boss sold minicomputers, and let her bring it home from work for a couple months for me to see what computing was all about, as he wasn't using it at the time. Good times.
That looks great! After I clear my project catalog a bit, I'll have to build one. 🙂
Project catalogs never shrink, they only grow! :D
@@smbakeryt 🤣 That's certainly true! One thing I'm already most of the way through collecting parts for... is a replica Mark-8 personal minicomputer (I think it was called?), so I'll get plenty of 8008 experience with that. Your board uses modern components for more features in fewer chips, which is quite interesting, while the Mark-8 will be more "period accurate" (but with much, much, much less RAM, etc.).
@@derekchristenson5711 The mark-8 originally what I was thinking of building! :D Still might give it a shot one of these days.
Looks like a computer I built back in the days. I used a hardware multiplexed display with the same driver IC you used , the reason back then was that that chip in a ceramic package was very expensive. The scan was using a 7489 16x4 ram.
An 8008 SBC? I haven't even started the video, but I already know I want to build one! ;-)
Seeing the H-9 brings back memories when I worked for Heathkit. I wish I still had the original plans, because I built a kit with 2 IC's that converted the H-9 from
12-lines to 24 lines on the screen. Maybe someone out their will have that kit conversion and respond to Scott about the kit.
Several folks at SEBHC have talked about this modification, and at least one person has a terminal with the modification installed. What we've seen so far I think is more complex than just a couple of ICs -- the pictures I saw looked like a fair bit of rework. The other popular modification was to add lower-case support and I think that required two chips (one of them being a second character ROM)
@@smbakeryt - My mod just had 2 IC's on a PC Board I created, and required 3 cuts on the main board, and then wires added to my, (very small board) that was just tucked away inside the case. This was done in 1977 or 1978, not sure, it's been so long.
Heathkit put out a small news letter back then for a short period of time which I contributed to. I also setup the first Computer Club at store #4 in La Mesa, CA.
Awesome video and a great amazing channel! I read your bio and I share the same interest!
I wonder, could the weird bus architecture where when writing to an I/O port the data ends up on the address bus also be the reason why the Z80 has I/O instructions that put the I/O address on the lower half of the 16-bit address bus and the data on the higher half of the address bus and that this was done for some sort of backwards compatibility with its Intel counter-parts?
And it has illuminated keys on top of everything 😄
Best channel on the Internet :)
Tell your friends! :D
Love it! Great idea.
Brilliant project. Any chance of a rev with easier to source display drivers might be in the works? In recent years I have built micro controlled versions of the DEC PDP 8 and 11/40 as well as the IMSAI, Altair and Kenback . Maybe someone can come with a case similar to the original H8 and have a kit for another outstanding early 8-bit box.
Hint, Chris Davis at Ad Water and Stir might be the guy to work out the enclosure,; his Altair box is outstanding.
I still have my H8 built in 1977 and several others I picked up over the years.
I absolutely love all the work and support you have provided for the H8 !!!!!!!!!!!!!!!
I do have a variant that uses TIL311, but they are not necessarily easier to source. Most other options for driving the display would require dropping resistors (DM9368 is really nice in that no dropping resistors are needed) and this blows up the component density on the board. Another option that has been proposed would be to use an FPGA or an Atmega as a slave to multiplex the displays but the disadvantage of this is that you're adding very modern components to what is supposed to be a vintage project.
It happens far too often where i find a great chip to run a 7 segment display. Just to find out it’s impossible to buy. Why is that!?! There are some great 7 segment drivers that were made that are just lost to time.
Eh.... those TIL311 clones from the UK are $3 if you buy 100.... ask me how i know, lol...
My 130 were $3.40/ea with tax and shipping
8008 and it runs forth?
Damn... i low key want one...
Typically takes a couple of people a year or so to release a board but you just slap out a board over a fortnight.
This is a good point. He’s got a team of 80’s engineers working round the clock on this stuff. Has to. It’s just not possible for one person to produce computers like this.
The key is re-use. Once you build a library of useful patterns and snippets of schematic, it's easy to throw together a new board in a short amount of time.
I'm interested in a set of those keycaps but can't seem to find them on Max Keyboard. Were they special order?