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Old 14th Apr 2019, 6:08 pm   #163
SiriusHardware
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Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,482
Default Re: MK14 schematic revisions

Yes, the PE VDU was a much more sensible beast than SOC's own effort. I've never seen one.

For the SOC VDU, be aware that one of the ICs on that - the character generator IC - is quite a specialised IC and may be hard to find now. It was actually an option which did not automatically come with the VDU kit, you had to pay extra for it. It still sort of works without it, but only in dot-matrix (graphics / pixel) mode. If you want to use it in its text / character output mode you'll need the character generator IC.

If Slothie manages to track the VDU connections to the rear edge -and- removes the images from 0200-07FF (a big ask) then there is the possibility to place a 'ram pack' in between the MK14 and the original SOC VDU, or just by itself to give the machine a respectable extra 1.5K of RAM.

Unfortunately the butchery required to my issue II board to get rid of the images in that range would not only be too great now, it was too much for me to consider then and I never did it.

Even when hooking the VDU into the MK14 in the manner intended there were a few required changed such as track cuts and a change to a 4Mhz crystal, so it was quite a destructive process. Mine still bears the scars, even though I have modified it back to near original state, except for the keypad of course.

..I remember those stick-on IC diagrams, a good idea I thought but of course you always ran out of the common ones pretty quickly.
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