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Old 23rd Apr 2018, 1:15 am   #21
SiriusHardware
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Join Date: Aug 2011
Location: Newcastle, Tyne and Wear, UK.
Posts: 11,482
Default Re: MK14 schematic revisions

I have to admit that sounds fantastically reasonable. Last time I looked at the possibility of having a PCB made in low quantities the cost was easily up into three figures.

This CAD package you've used to produce your project, is that freeware or commercial software, and for what OS(es) is it available?

Unfortunately I can't easily measure the key spacing on my MK14 as the replacement keypad is mounted millimetres above the main PCB and the wiring from it is tack-soldered onto appropriate points on the original keypad tracks and all hidden carefully underneath the keypad - which makes it difficult to remove the keypad far enough to perform measurements. (See attached image #1 - note the fairly haphazard alignment of some of the key legends, which were laid down using rub-down transfers and sealed in place with clear varnish).

I did this sometime early on in the life of the MK14. The keypad is not built on a PCB, but on ordinary stripboard / veroboard. To disguise that and make it look a bit nicer I placed a sheet of black modeller's 'plasticard' over the top of it and cut it to the same size before drilling holes to allow the pins of the switches to pass through it.

For the (as yet incomplete) Karen-O PIC14 emulator I used the same method of lettering the keytops but made a slightly better job of it (image #2), as I'm now older and rather more more patient.

As it happens the keyswitches I found for that emulator are nicer, with a better action than those currently fitted on the MK14 so I may consider swapping the keyswitches over to the keypad on the actual MK14 at some point.
Attached Thumbnails
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