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Powertran Cortex

Just got my Cortex PCB's
I didn't expect them to still be in what must be the original tissue paper from almost 30 years ago.
I don't want to open them !

NOS Cortex boards.jpg
 
Hi Jim,

Very cool to see them wrapped up like that! You should have bought two sets... BTW, good luck with the build.

As far as I'm aware, there was only ever one set of ROMs in circulation. They identify as Cortex Basic Rev 1.1 when you power up the computer/emulator. Since the project was published over late 1982/early 1983 period, Jan 10, 1983 sounds about right.
 
So i did open them.
Heres a scan of the top of the main board, i can do the other side and other boards if people are interested.
The original scan is at 600dpi / 7.5 meg

Appears to be the same rev as the ETI boards though for some reason it doesn't have an issue number where the ETI drawing shows one.

cortex pcb top smaller.jpg

Jim
 
Cortex V Cortex 2 differences

Cortex V Cortex 2 differences

Hi All,
Does anybody know the differences between the Cortex and the Cortex 2
Was it just the case or was the system board different as well ?
Will a original Cortex pcb fit in a Cortex 2 case ?

Thanks,

Jim
 
mnbvcxz said:
The Cortex 2 was the same board in a different case.
Click to expand...

I can confirm this. I had/have a 'Cortex 1' (actually two of them) and I built from kit form a Cortex II for my friend back in the day. It was re-boxed to look like a BBC Model A/B. I think it was at the tail end of its market influence so Powertran just tried to jazz it up a little.
 
Jim Hearne said:
So i did open them.
Heres a scan of the top of the main board, i can do the other side and other boards if people are interested.
The original scan is at 600dpi / 7.5 meg

Appears to be the same rev as the ETI boards though for some reason it doesn't have an issue number where the ETI drawing shows one.

View attachment 6477

Jim
Click to expand...

Can you do the other side as well please? It might be useful to have and you are the one who can make it happen!
 
Some pictures of what i've just bought from the same guy selling the PCB's on Ebay.
Apart from a few missing TTL and RAM chips it's a complete basic Cortex 2 kit.
Who'd have thought a unbuilt kit would turn up after almost 30 years !
cortex 1-s.jpgcortex2-s.JPGcortex3-s.JPG
 
Well that's going to make construction a lot easier:D
If he had advertised an almost complete kit. he might have got a lot more money for it, I don't think I could get the TI chips now ( unless he has more kits!), which is why I did not bid on the PCB's.
Although if anyone is DESPERATE, they should enter tms9995 into the ebay search function, and they will see a company offering this chip for about £140, which seems a bit excessive to me.
Best of luck with your build.

I did buy a pair of tms9900 cpu's, it might be interesting to benchmark the cortex and a machine built with a 9900 and 16 bit memory to see which is faster.
 
Indeed, thought it's missing the TMS9909 floppy disc controller and i will want to put floppy drives on it.

I did have a quick look around the net before i bought the boards and it did seem that most of the chips are available with reasonably sensible prices from the US or China etc.
I also work in electronics and might be able to pull in a favour from some of our suppliers to locate other parts.
But now i've got the complete kit thats not quite such a problem.

I see there was a piggy back board that solved the problem of the rare TMS9909 FDC chips, need to look into that more.
The TMS9902 serial port chip seems to have been used in the TI99/4A and i should be able to get one of those quite cheap.

Has anybody got the missing Cortex user group mags ?

My intention is to creat a web page(s) covering the build if people are interested.

Thanks all,

Jim
 
Chips.

Chips.

Managed to get hold of a couple of TMX9909 FDC (pre production TMS9909) chips so that will save messing around with the floppy daughter board.
Also found the TMS9911 and 74LS612

Just got to wait for them to get here from various parts of the world.

Anybody else noticed that theres a IC14a (Nand gate) on the circuits but not trace of it on the board or parts list.
I guess this was one of the late changes.
I'll buzz out the bare board and see whats actually there instead, maybe they found a spare gate from another package.

Jim
 
Jim Hearne said:
Managed to get hold of a couple of TMX9909 FDC (pre production TMS9909) chips so that will save messing around with the floppy daughter board.
Also found the TMS9911 and 74LS612

Just got to wait for them to get here from various parts of the world.

Anybody else noticed that theres a IC14a (Nand gate) on the circuits but not trace of it on the board or parts list.
I guess this was one of the late changes.
I'll buzz out the bare board and see whats actually there instead, maybe they found a spare gate from another package.

Jim
Click to expand...

Gotta say, Jim, you seem pretty resourceful! As I said before, good luck with the build and getting it all together.
 
Website now up...

Website now up...

Hi Guys,

After much encouragement in the early days, I went ahead and pushed for my goal to encapsulate everything on a dedicated website: powertrancortex.com. The site, as of tonight, is where I envisioned it to be.

I had two goals. Firstly, I wanted it to be easily accessible, rather than having to trawl through all these posts to find a links to the FTP site etc. Secondly, I was encouraged to extend the the existing material by adding all the disks I had in my possession along with tools to make use of them on a real Cortex.

It has taken more or less all my spare time in the last 8 months to do this but it's all now available. I went through close to 100 disks to consolidate them into clean 'release' disks so that they were uncluttered and usable. I developed utilities so that anyone who has a Cortex with a TMS9909 Disk Interface can make use of them (Jim Hearne, looks like you showed up at just the right time!). Alternatively, everything works with my Cortex Emulator (many changes since the one that's on the FTP site).

Please check it all out and give relevant feedback so that I can make corrections as needed.

Evidently, my wife has a very long list for me...

Enjoy!
 
PCB Scans.

PCB Scans.

Hi All,
I've now scanned all the Cortex PCB's at 600dpi
They are on my web site here http://www.quantums.info/cortex/cortex pcb scans 600dpi.zip
They are about 18 meg !
Please feel free to upload them to other sites and the ftp for backup purposes.

They aren't totally perfect as the boards were too big for the scanner so i had to scan in 2 halves and then join them together.
But they are fine for following track layouts.

Jim
 
mnbvcxz said:
I did buy a pair of tms9900 cpu's, it might be interesting to benchmark the cortex and a machine built with a 9900 and 16 bit memory to see which is faster.
Click to expand...

The Cortex, with its TMS9995 processor, is significantly faster than the 9900 (~twice the 'power') because the 9995 does instruction prefetch.
 
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