Powertran Cortex

[Jim Hearne]

At the moment,
Expansion Ram card, Parallel port card (+ joysticks), sound card (+joysticks), hard disk controller, i'm sure there are others I've forgotten.

Jim

[mnbvcxz]

Where can I find these expansions, are they designed for any particular system, like the Cortex?

[Stuart]

I think the E-Bus motherboard is probably for the MPE 9995 cards and not a cortex so maybe it should go with those.
I don't think it would work with the cortex without mods, and i'll have the PP95 for testing my 74ls2001 on until I make an e-bus expansion for the cortex.

Jim

No problems, I'll transfer the backplane from your box to the other Jim's box.

To use an E-bus card with the Cortex, presumably as a minimum you'll need a gender changer/extension cable as both the Cortex and the cards have male connectors?

[Jim Hearne]

Where can I find these expansions, are they designed for any particular system, like the Cortex?

They are all for the Cortex really, and the PP95 (industrial Cortex) and MPE 9995 boards we have been talking about recently.
E-Bus was a Texas Instruments bus so it's probably on some of there other systems from the time but personally I don't know.
Most of the publicly published boards were in ETI magazine or the users group magazines, Stuart now has some more that have been donated by Stephen from MPE , a company that made expansion cards for the Cortex when it was current.
Have a look at Dave H's (TMS9995 here), the magazine articles and user group magazines are there http://www.powertrancortex.com/

Jim

[Jim Hearne]

No problems, I'll transfer the backplane from your box to the other Jim's box.

To use an E-bus card with the Cortex, presumably as a minimum you'll need a gender changer/extension cable as both the Cortex and the cards have male connectors?

I've not actually fitted the E-Bus connector to my board yet as I was never quite sure what gender or width it was.
I'd had the idea you could plug a single E-Bus card directly into the Cortex but I guess not.
(Actually, I've checked back now in the ETI parallel port article and it says that you can fit a female connector to the motherboard if you wish to let you plug an E-Bus card in directly).

You can get IDC versions (for ribbon cable) of the DIN 41612 connectors so I can use a couple of those to make an extension to a backplane.
I might already have something I can use for that, I've a few passive backplanes for DIN 41612 connector cards in a box somewhere, though I can't remember if they are A+B or A+C.

Jim

[Stuart]

The Mk 1 Cortex from MPE is now alive again, after some TLC:

-- Strip down and clean.
-- Replaced shorted tantalum cap in the power supply which blew a pair of the diodes.
-- Replaced the ICs which had been scavenged years ago for other projects.
-- Replaced 22 TTL ICs which had rusty legs.
-- Mounted the TMS9902s and TMS9929 on DIL headers as the legs were corroded and brittle.
-- Seven of the eight CPU DRAMs are dead.

The PCB has a couple of mods on the back around the video circuit, which might possibly be to improve the display? There are photos below, if someone wants to work out exactly where in the circuit the connections are. The diode is a 1N4148, and the resistor is 100 Ohms.

http://stuartconnerdownloads.me.uk/~...f/DSCF0287.JPG
http://stuartconnerdownloads.me.uk/~...f/DSCF0289.JPG
http://stuartconnerdownloads.me.uk/~...f/DSCF0290.JPG

Stuart.

[Jim Hearne]

The ex MPE PP95 system which I collected from Stuart is now residing in my workshop awaiting a full refurb.
I've also got 125 5.25" disks of MPE software which I'm archiving using Dave's PC comm util (www.powertrancortex.com) software to upload disc images to the PC.
Progress has been slowed by a couple of Wabash brand disks which decided to shed there oxide coating onto the drive heads, and either that or the cleaning afterwards has put the drive out of alignment.
I picked up another drive today.
Disks as I image them will be uploaded here: http://www.quantums.info/cortex/MPE%20Disks/
There is an Excel format spreadsheet in that directory that I will update as I progress.
If anybody has any requests please let me know, otherwise I will steer clear of the unbranded ones to start with, probably doing all the Dsyan ones first as I've had no trouble with them so far.

Jim

[Jim Hearne]

Hi All,
Some more disk images on http://www.quantums.info/cortex/MPE%20Disks/ and the index updated with a few more disks that have issues, I will be going back to those at the end.

Jim

[Jim Hearne]

Hi,
I've just spotted that the non 5V end of R26 (1K pullup on modulator input) doesn't actually connect to anywhere except a unused pad on the board.
Unless it was there for use with another type of modulator that fitted the other holes ?

I tried connecting it on my board but it didn't seem to make much difference to the picture.
The TV out on mine has started getting worse, it's now difficult to find a combination of colours that doesn't cause the picture to loose sync,
I'm convinced it's some problem with the dc restoration clamp circuit but several scope sessions haven't found anything wrong.

Jim

[JEH]

Have you modified your sync circuit as in http://www.quantums.info/cortex/Cort...Feb%201986.pdf ?

Or are you using the video circuitry from http://www.quantums.info/cortex/Cort...Feb%201986.pdf - I can't find the 1k R26 in either circuit (well, the former has a 27k R26 between Q2 and the FF clock).

OK, found R26 1k pullup in my printed CortexII schematics. Have you tried adjusting R37? It seems to be the voltage switched to Q5 by the sync pulse.