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Powertran Cortex

help needed to restore cortex to working condition

help needed to restore cortex to working condition

HI,

I have a cortex that I built in the 1980's.

Its been in the loft for 20 years and I have often thought about trying to get it working.

any help or encouragement would be great.

it has the later Maplin display board and 256k of ram with the ls2001 replacement header and the eproms were reprogrammed for the later disk drive chip ( changed them to a 2764 on a header board)

I do hope to hear from someone that has a working machine.
 
You've probably got the most advanced machine of all of us. Me, & AndyP have working machines in the UK (although we both seem to have slight sync problems in that the leftmost side of the display is a bit hidden) I have a floppy on mine, but the cable's damaged & I'm waiting till I have a few bits to order before getting a (few) replacement IDC sockets. Have a look back through the thread.
I'd be inclined to test the PSU separately (with a dummy load (car bulb or something)) before connecting to the logic board, also do a shorts test on the power conections to the main board. Usual faults for a machine that hasn't been powered up for 20+ years are dried out power supply electrolytics (ripply outputs & occasionally a minor explosion), Tantalum capacitors on the PCBs shorted out (shorts the power supply & can burn tracks off the pcb, sometimes there's one on the reset, which stops the machine resetting), oxidised I/C sockets (cured by removing & reseating chips), damaged memory (caused by cosmic rays!), and dirty/oxidised keyboard contacts.
We'd love a dump of the roms, & if these quick notes go over your head, we're happy to help further!
 
right then....all i need to do is get the workshop sorted out and explain that I am hiding in the loft trying to ressurect a machine hedden there for 20 years of marriage...should be easy !

seriously I will try to test the PSU and check out the machine, last I tried it just sat there but the voltages were fine, might head for the reset switch and see if the cap has gone short ! probably be a few weeks beofre I get a chance but great to hear that I do not have the last one.
 
There are links above to the whtech archive which has software, schematics & reprints of the original ETI articles etc. I can't be bothered going back through 23 pages though!
I've done a proper loft conversion now, there's no way that the CDC 14" disk drives would go up a ladder, I was worried about the stairs with 2 blokes and over a hundredweight of drive between us. Next house has to have a semi-basement, so I can get to use the (about 1/4 ton of) band-printer.
 
Excellent! We seem to have found another Cortex user :) Welcome!

I've been pretty busy of late, but I will try to get the games Andy sent me up onto WHT this weekend.
 
when I first built mine it had the display too far to the left...

are you on a RGB set up or the modulator ?
 
Mine hasn't got a composite/rgb output (it has a hole in the case for a din socket, but nowhere on the board (or the schematic even!)for it to connect to) purely a modulated output.
you say "when you first built it the display was too far to the left", did you correct this? it looks like it could be firmware correctable.
 
It's a long time ago but I remember taking the video connection from the input of the modulator and using this for composite to a TV...I think I used a couple of transistor stages to buffer it and drive it.

Some where i thnk i have the user group news letter with the "official" RGB interface and maybe even a copper diagram for the board...Will have a look next weekend.
 
Anyone still here? ;-)

Stumbled across this: the display being too far to the left - a design fault with the European VDP it seems. See:

<http://spatula-city.org/~im14u2c/vdp-99xx/e3/1982_TI_Europe_Proposal_for_9929A_Improvements_(inc._External_Video).pdf>

Section 3.1, para 2, on page 6 of the PDF.

(Many of the docs at <http://spatula-city.org/~im14u2c/vdp-99xx/> make interesting reading.

Stuart.
 
We are still alive, just even more busy than before.
very interesting - so there's nothing to be done except attack the chip with a dremel & an ion beam!
Thanks stuart.
 
74ls2001

74ls2001

I have been gifted with a nearly-complete copy of the preliminary data sheet for the 74LS2001 which I am in the midst of turning into a fully-functional document (much like I did for the Forth and BASIC manuals). There will be a few missing words here and there as the copy I received was missing a narrow strip at the end of each line of text. Sometimes it is easy to reconstruct a line, but there are instances where there is no clue as to what the missing text was.

One major advantage: the timing diagrams and the pin out are complete, so with what we already knew and the contents of this document, it should be possible to code a replacement for it.
 
Marinchip M9900

Marinchip M9900

Ksarul said:
TMS9995, one of your earlier comments reminded me of something I haven't thought of in ages. Marinchip Systems also built a TMS9900 board for the S-100 bus. I was looking for one of those for a long time but never did encounter anyone who'd ever heard of it or them. Thanks for the reminder. . .one more vintage 9900-family system for me to track down. :)
Click to expand...

I have a Marinchip M9900 S100 box - It's a huge Integrand chassis with M9900, 64k/128k RAM and two DS/DD 8 inch floppies. There's even the original manual somewhere. There are boxes and boxes of floppies for it. This is the machine used for the port of MDEX to the Powertran Cortex. There's also a Cortex and a Scandinavian industrial version of the Cortex. MDEX's big brother NOS was ported to this as far as I remember.

These machines all worked when last powered up. If someone wants them - just ask.

Stephen
 
spelc said:
I have a Marinchip M9900 S100 box - It's a huge Integrand chassis with M9900, 64k/128k RAM and two DS/DD 8 inch floppies. There's even the original manual somewhere. There are boxes and boxes of floppies for it. This is the machine used for the port of MDEX to the Powertran Cortex. There's also a Cortex and a Scandinavian industrial version of the Cortex. MDEX's big brother NOS was ported to this as far as I remember.

These machines all worked when last powered up. If someone wants them - just ask.

Stephen
Click to expand...

Er yes, I'd love to get my hands on that gear! I believe I remember you (along with Richard Roberts) from MPE?
 
Stuart said:
I'd love the Cortex ... and live in Southampton. ;-)

Stuart.
Click to expand...

Fine by me. I have two already :) More interested in the other stuff. If I find it doesn't have a lot more to contribute to the Cortex 'preservation project', I'll give it to Ksarul since he has a real TI fetish...

I'm hoping to have some news regarding building the Cortex ROM from source very soon...
 
tms9995 said:
Fine by me. I have two already :) More interested in the other stuff. If I find it doesn't have a lot more to contribute to the Cortex 'preservation project', I'll give it to Ksarul since he has a real TI fetish...
Click to expand...

I'll take the 'industrial' Cortex as well if there are no other takers. I know another chap in the UK who will probably bite my arm off to get it and put it to good use.

Stuart.
 
spelc said:
I have a Marinchip M9900 S100 box
Click to expand...

I'm running seriously short on space but..... Wasn't that the original Autocad machine? If Ksarul can't take it, and you're not TOO far away, and you want it gone, then can you put me on the list please!
 
tms9995 said:
I'm hoping to have some news regarding building the Cortex ROM from source very soon...
Click to expand...

If you're rebuilding the code, what do you make of this? VDPDSR module, page 10, last line in the 'TEXT MODE' block - JHE FTMODE. Shouldn't that be a JL REMCUR jump (to the following block) followed by a BLWP @FTMODE since FTMODE comprises a WP pointer and PC pointer? [I'm working on porting the code across to my TM990 9900-based system so have been looking quite closely at it.]

Stuart.

(tms9995 - also sent you a PM)
 
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