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Powertran Cortex

galexa said:
Hi all
I have just skimmed this long and ancient thread. Although I've searched for info on the Cortex before I recently realised that adding powertran to the search made things much better. My interest being that I built one from the kit and ETI instructions back when it was released.

So finding @tms9995 's website and reading the user group newsletters, I was reminded that, like @planetming above, that I also won a prize for a bit of software. I placed second with GDesign, a sprite designer, which I wrote mainly to help with programming the graphics for Mighty Muncher, a Pacman ripoff that I also wrote with my brother-in-law.

I also submitted a hack for making the 'bell' output more 'musical'. This was a bit of a shock to me as I'd completely forgotten about it and now couldn't even imagine how I did it!

In trying to search the user group PDFs I realised they hadn't been OCR'd so I've done that. They won't be perfect but it does make searching easier and if anyone wants them I'm happy to upload them somewhere.

Thanks for triggering the memories.

Gary
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Welcome to the current iteration of the world of the Cortex, Gary. OCR versions of the newsletters are a very good idea. We just need to get them up onto the new somewhere (the Powertran Cortex website would definitely be a good place to start. . .).
 
Ksarul said:
Welcome to the current iteration of the world of the Cortex, Gary. OCR versions of the newsletters are a very good idea. We just need to get them up onto the new somewhere (the Powertran Cortex website would definitely be a good place to start. . .).
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Presumably you mean http://powertrancortex.com/ ?
That's where I downloaded most of them and why I tagged @tms9995 so that would make sense to me but no reply to the tag so far. I also got the 'missing' ones from the FTP site (mentioned earlier in this thread). The zip of all 21 OCR'd is 108MB so too big to attach here. I'll give it a few days and if nobody can give me somewhere to upload I'll stick it on googledrive or something, temporarily, and post a link here.

Thanks for the welcomes!

Gary
 
Hi All,

I have recently got into electronics & retro computing in a big way, and in doing so, I've ended up retracing the path my father took 30+ years ago. Refurbishing and reverse engineering computers from before my time is immensely rewarding to me, but finding documentation is often the hardest part.
I've spent ages searching for the user group newsletters, and I've of course found powertrancortex.com and ftp.whtech.com, but they're both missing issues #1, #5, and #8. I'm hoping one of you in this thread has a copy of them.
In particular, I would really like to find a copy of UGN #1, because that's the one that features the 'Bulletproof RAM' mod which was created by my father. It would mean so so much to me to be able to read his submission from all those years ago.

-Alan
 
Vimlopop said:
Hi All,

I have recently got into electronics & retro computing in a big way, and in doing so, I've ended up retracing the path my father took 30+ years ago. Refurbishing and reverse engineering computers from before my time is immensely rewarding to me, but finding documentation is often the hardest part.
I've spent ages searching for the user group newsletters, and I've of course found powertrancortex.com and ftp.whtech.com, but they're both missing issues #1, #5, and #8. I'm hoping one of you in this thread has a copy of them.
In particular, I would really like to find a copy of UGN #1, because that's the one that features the 'Bulletproof RAM' mod which was created by my father. It would mean so so much to me to be able to read his submission from all those years ago.

-Alan
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I have them from issue 1 to 21.
#1, 5 & 8 attached.

Jim
 

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Vimlopop said:
Jim, I cannot thank you enough for those! You don't know how much this means to me. I wish you all the best.

And, Thanks for the warm welcome everyone!
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No problem, I can't take credit for scanning them, i got them from somebody else.
I'm surprised there isn't a full set on the net still.
I've got a fully expanded Cortex 2 which i built from a unbuilt kit in 2011 and i've got a PP95 which is a industrial version of the Cortex which needs a full restoration one day.
I did your Dads Bullet proof RAM mod to my Cortex.
 
It’s been a long time coming…..

I had a cortex back at the beginning and found it a fun toy….so anyway on eBay a couple of years ago I sourced a spare cortex that was advertised as not working.

To cut to chase it’s been in the loft for a while as I was working but now find retirement has left me with a fancy of playing with it.

Powers on ok, PSU voltages at 12.01 v , -11.8 vote and 4.75 volts capacitors seem ok but will probably change them soon anyway ( or go for a SM PSU.

I don’t have a tv to feed it UHF so taking the modulator feed in signal ( with an 10k resister to pull up to the 5v line.and passing it to a vga converter is the plan.

So the main board is neat and tidy but some of the chips have very dirty legs, it lacks the ebus chips but that should not be a problem.

What I am seeing is it flashes the mem led very briefly( just a flicker - if I recall correctly it should be about a half second while it loads the rooms ) and the Basic led is constantly on. No idle light flashing at all.

My first thought was it might be the caps on the reset buttons but that all checks out ok, I can logic probe the signals to the cpu etc as reset goes low when I push the buttons.

I then double checked the chips against the parts list ( you never know ) but all chips checkout.

I think I am in for some long trouble shooting sessions, it seems to just be sitting doing nothing, have run as many chips as I can through a chip tester and they all report as good logic.

Any thoughts or tips from someone else that’s done a rebuild ?
 
First thought is 4.75V is only *** JUST *** on the edge of TTL acceptable, and that was when the devices were new 30 odd years ago...

I would look to get the +5V rail closer to +5V...

Of course, it could be what you are using to read the voltage with, or where/how you are reading the voltage at.

Dave
 
daver2 said:
First thought is 4.75V is only *** JUST *** on the edge of TTL acceptable, and that was when the devices were new 30 odd years ago...

I would look to get the +5V rail closer to +5V...

Of course, it could be what you are using to read the voltage with, or where/how you are reading the voltage at.

Dave
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Using a handheld digital volt meter and taking the voltage across the power connector, checked with a second meter and that give 4.9 volts so I think the power rails are ok.

I am not certain what it’s actually doing - suspecting that the video side may not be working with the video to vga converter I am at the moment just looking for the 4 lights to diagnose what it’s trying to do.

it’s a long time since I booted one of these up.

Of the 4 lights on the panel I can’t remember what should normally be lit up once the rooms have loaded. I think I remember the idle light is normally flashing and the other lights would be off - what I am seeing is the map light flashes very briefly and the "Basic" light is on all the time ( even when i do a reset/break ) - the basic light feels like it is stuck on ( BUT - can someone with a working system let me know what the lights would do on a normal start up )
 
I don’t have one, but obvious first steps are,
Reset on cpu pin 22,
Check the clock is working on the cpu pin 3,
Take a look at the ram, if you can put it in a chip tester. For most things of this vintage (spectrums, c64, coco’s) it’s usually the ram…
 
I popped a reply in here to David, but it's been moved into its own thread.
Here
Probably best as this one is getting a bit long now :)
 
This may be of interest to those that want to try the disk drive system with the 2797 chip....manual for CDOS 2 and the back page gives you the boot code to be burnt into the roms to allow it to work.
 

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