View Single Post
Old 22nd Apr 2018, 11:02 am   #19
SiriusHardware
Dekatron
 
Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,485
Default Re: MK14 schematic revisions

By 'nicer' keyswitches I didn't mean 'more authentic' as in dome switches, I meant 'nicer to use', like the high-end full travel 'Cherry' type used in the older computer keyboards. Those modern tact-switches tend to have a rather 'hard' and unyielding feel, with limited travel. If you take one apart you'll find it is just a self contained dome switch.

If you did want to try making the keypad more authentic by using dome switches, some of the hard work has already been done for you as one of the other individuals making replica PCBs has gone so far as to have some keypad overlays similar to those used on 'dome switch' MK14s made. (This was already discussed in other recent threads regarding the MK14, so I refer you to those).

Pretty much all of us here are incurable hoarders, so we all share in your triumph over finding that bit of cable. You've gone to a lot of trouble to keep the machine reasonably authentic by using hard to get RAM when it might have been easier to use a slightly later, larger 8-bit wide SRAM, so perhaps you should also install your display on ribbon cable to keep it looking original.

Back in the day, we often used to put our MK14s in enclosures and for that reason it was common, some time after the machine had been built, for the display to be removed and extended on wires / ribbon cable to a more ideal location on the enclosure. Mine went through several phases of being installed in various enclosures until about ten years ago, when I decided to revert it back as far as possible to its original self contained single-board format. The only component still mounted off the board (and on a heatsink) is the regulator. A fully populated MK14 typically draws (from 5V) around 0.5A, nearly half of which is taken by the PROMs containing the operating system.
SiriusHardware is offline