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Unknown 1802-Based System

acgs

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Apr 24, 2022
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237
Glad I found something that helped out!

I want to be clear, though. The Jameco ad doesn't specifically state that the keyboard is from a Vydec. That's only my conclusion based on how electronics re-sellers worked back then. I remember, for example, finding a homebrewing article that listed a Radioshack part number for surplus TI-99/4A keyboards. Radioshack had apparently bought up TI's stock after they dropped the TI-99 line.

My conclusion is backed up somewhat by this article in the Dec. 2, 1981 issue of the NY times:

https://www.nytimes.com/1981/12/02/...lant-and-lays-off-1100-in-office-company.html

Since Exxon was "restructuring" 10 months BEFORE the Jameco ad, and had found/acquired 2 newer word processor systems from Compucorp, it seems likely that they dropped the Vydec line and sold their surplus stock of parts. In my opinion, that is probably how Jameco came to be selling them.

It would also explain why the keyboard was so much cheaper: surplus overstock can be bought for a song.
 

DeltaDon

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Dutchess County, New York, USA
My Quest Super Elf was outfitted with a Jameco keyboard connected to the Netronics RS232 terminal board when I expanded it to use a serial terminal, but not anything like NeXT has attached to his machine. So no help with pin ID.
 

Bruce Tomlin

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Here's a better disassembly of the code.

I've been working on an interactive disassembler and have been disassembling everything I can find to test it. 1802 is particularly annoying to disassemble because of the split address loads, but I learned a few things. Once I figured out the "macro" that it used for subroutine calls, it went a lot faster.

Definitely this is some version of that keyboard, but someone went to the trouble of making a lid with punch-outs to match the keyboard. And the 6847 is an interesting choice for video, it's not really high quality, but it gives you a display that works on a regular TV set with little trouble.
 

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NeXT

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I finally tracked down a small-ish color TV that had manual tuning. Ironically for an RCA microprocessor it's an RCA TV. This uses that old style mechanical tuning where each "channel" has its own adjustment for coarse tuning and then you let AFC lock it in the rest of the way. I just turned that off, tuned it in and we got a clean color picture.

IMG_4247.JPG
 

acgs

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Apr 24, 2022
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237
Nice system, NeXT. I would've bought that back then, if I'd seen it at a computer store. I've always thought whoever put this together did a nice job of making it look professional. But, somehow, that "monitor" makes it look even more like it was mass marketed.

The screen size looks spot on for this computer, too. Amazing how the right match-up of vintage tech makes everything work just right, isn't it?
 

G7VFY

Member
Joined
Apr 1, 2023
Messages
29
You want to ask this guy:-

I have never seen a 1802 based computer that used the 6845. All the machines I have seen, used the RCA video chip family:- RCA CDP1869/CDP1870

If you look through the text dump you might find a list of commands and some copyright info. It also might be worth comparing the machine code monitor to other ones written around the same time.

It is also possible that this mystery computer builder was a radio ham and might have based it on a published design. The Motorola 6845/6847 were much more widely available than the RCA equivalents. The screen font reminds me of the Coco's, Dragon32 and Acorn atom. Builder might be know to someone in the 1802 community.

I've just discovered that there was meant to be an 80column card for the COMX35, based on the 6835 video chip, according to the wikipedia page for the comex
 

waltermixxx

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Apr 3, 2015
Messages
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Canada
howdy, I think there is either an IpsoFacto or Viper artical about adding a 6847 to your Elf, or VIP. I will try and dig it out, it might help. but those would be keywords to do additional searching with VIPER or IpsoFacto was an RCA1802 user group out of Hamilton, Ontario. so that computer should have it's roots in Canada. I will do some digging and see what I find. :) Cheers. :) if I find the artical it might be helpful as they might discribe the rom :) found an artical on the 6847with the elf: http://www.cosmacelf.com/publications/newsletters/ipso-facto/ipso-facto-13.pdf
 
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G7VFY

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Joined
Apr 1, 2023
Messages
29
You want to ask this guy:-

I have never seen a 1802 based computer that used the 6845. All the machines I have seen, used the RCA video chip family:- RCA CDP1869/CDP1870

If you look through the text dump you might find a list of commands and some copyright info. It also might be worth comparing the machine code monitor to other ones written around the same time.

It is also possible that this mystery computer builder was a radio ham and might have based it on a published design. The Motorola 6845/6847 were much more widely available than the RCA equivalents. The screen font reminds me of the Coco's, Dragon32 and Acorn atom. Builder might be know to someone in the 1802 community.

I've just discovered that there was meant to be an 80column card for the COMX35, based on the 6835 video chip, according to the wikipedia page for the comex
I meant to say 6845 and not 6835.
 

G7VFY

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Joined
Apr 1, 2023
Messages
29
howdy, I think there is either an IpsoFacto or Viper artical about adding a 6847 to your Elf, or VIP. I will try and dig it out, it might help. but those would be keywords to do additional searching with VIPER or IpsoFacto was an RCA1802 user group out of Hamilton, Ontario. so that computer should have it's roots in Canada. I will do some digging and see what I find. :) Cheers. :) if I find the artical it might be helpful as they might discribe the rom :) found an artical on the 6847with the elf: http://www.cosmacelf.com/publications/newsletters/ipso-facto/ipso-facto-13.pdf
What's interesting is that the 6847 was meant to be NTSC? which kind of makes sense, but a lot of computers, both PAL and NTSC, also used the 6845.
Also, in the UK, Acorn computers used the 6847 on their first computer that plugged in to a TV, the Acorn Atom. It had high resolution monochrome graphics, and if you wanted colour, you needed to purchase a colour card. I worked for an Acorn Dealer and I can tell you that this card was pretty dreadful. The colours were not stable and it was really hard to get colour text, and graphics, at the same time.
 

Bruce Tomlin

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Just a reminder for those who aren't familiar with it, the 6847 was the video chip used for the TRS-80 Color Computer and the Dragon 64, as part of Motorola's generic low-cost 6809 design. It was also used in the TRS-80 MC-10 and with a 6800 CPU in an APF video game system, among other things.

It was completely unrelated to the 6845. The only thing in common was being a video chip with a Motorola part number. It only supported 16x32 text and some graphics modes, and not even lowercase text. It provided NTSC color support, but I'm not sure how that worked with Dragon 64 in the UK.
 
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waltermixxx

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Location
Canada
What's interesting is that the 6847 was meant to be NTSC? which kind of makes sense, but a lot of computers, both PAL and NTSC, also used the 6845.
Also, in the UK, Acorn computers used the 6847 on their first computer that plugged in to a TV, the Acorn Atom. It had high resolution monochrome graphics, and if you wanted colour, you needed to purchase a colour card. I worked for an Acorn Dealer and I can tell you that this card was pretty dreadful. The colours were not stable and it was really hard to get colour text, and graphics, at the same time.

Yup I have an Acorn Atom, I love that machine, as much as my Cosmac VIP. i used one of Zipsters boards (designed for the TRS-80 Colour computer) to get composite NTSC Colour output on the Acorn Atom. :)
 

jqavins

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May 19, 2023
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Hi. I'm new to the forum here, but I cut my teeth on 1802 coding. (I'm super duper rusty). The following statement intrigued me:
Once I figured out the "macro" that it used for subroutine calls, it went a lot faster.
Those call and return routines are similar to what was commonly used inside RCA labs, typically using R4 and R5, plus R6 as a link register. Are you familiar with those? Are those something that everybody knows all about (and who does this guy think he is anyway)?

These routines are either modified from those or developed independently, which is believable since what has to be done is clear and there are only so many ways to skin that cat. Preserving D the way these routines do is a nice touch that the Labs' routines didn't, but these not using the link, which seems like a real shame.

I don't know if this helps at all with identifying that beast, but I guess any observation holds the possibility of helping.
 

GeSnow

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May 30, 2023
Messages
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IMG_0104.jpeg
This computer was built by grade 12 students in Vancouver Technical School. The students belonged to a electronics career prep program.
 

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GeSnow

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FYI, the bios on this server was programmed using HEX opcodes, we did not use any compiler.
 

GeSnow

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It finally showed up. The system indeed has absolutely nothing I can consider a brand, but it is an 1802. Dating of the IC's places it no later than 1982. From this point onwards if anyone can recognize the kit this was built from (and curiously if the layout of the keyboard is familiar to anyone!) please chime in.

The enclosure is beautifully done. I wish I knew who the last owner is because they did a very good job forming the steel and cutting the sides. It's indeed an extremely custom job but there's no name or signature anywhere.
CGS_11228_s.JPG

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The boards are all photo etched. There is no markings as to who manufactured them however both the processor and video board seem to refer to themselves as the "Color Machine".
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The backplane and power supply is equally unbranded.
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The cassette interface however seems to at least denote the various input and transistor pins.
CGS_11239.JPG

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The keyboard is pulled form something else. Doesn't appear to have any smarts. Don't give a toss what type of switch it is because who the hell cares?
Unfortunately the cabling back to the processor board is pretty jank. The red button seen earlier was directly soldered here but I noted all the current wiring points before I pulled everything apart.

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Edited: Further searching leads me to believe the keyboard is from a Vydec word processor. Both the 1400 and the 2000 have very similar but not exact key layouts but some of the special keys are in the exact same positions.
The keyboard was ordered from a Electronic Parts Surplus Magazine, I ordered them for the other Students.
 

NeXT

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So am I safe to guess you were a teacher or a teaching assistant at the time? Was this a design that was drafted within the school or supplemented in optional course curriculum if a teacher decided to have the students build their own computers?
Here in Kamloops my high school still doing drafting, electronics and board etching as part of the technical courses until the middle of the 2000's but it was usually much simpler projects near the end.

Edited:
Since you have the same Vydec keyboard and cabling would I be able to ask you for some additional technical info/photos for things like how the wiring arrangement?
 
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