LK201 emulation

Peter Coghlan cctalk at
Mon May 18 08:09:44 CDT 2020

Paul Koning wrote:
> Gentlepeople,
> I've been having problems with broken LK201s, so as a workaround I created
> an adapter that connects to a standard PC USB keyboard and makes it look
> like an LK201.  It's based on an Arduino (specifically, Adafruit Trinket M0,
> an amazingly tiny yet powerful small microprocessor).
> It's working at this point, though it needs a few small software tweaks to
> make it complete.  I'm going to turn my breadboard into something slightly
> more polished.
> Question to the list: is this something that would be of interest to others?
> If yes, I can make the design available.  Perhaps the PCB layout and parts
> list.  I don't think I want to get into building units for others, though.

I also find myself with several flakey LK201s.

To be honest, I wouldn't be interested in replacing them with PC keyboards.
I'd prefer to get my LK201s back in action.

If the issues are in the keyswitches or the flexi-print stuff connecting them
to the electronics, it looks like it will be nearly impossible to do anything
with them.
However, if it turns out that the issues are in the electronics part of the
keyboard and they are not easily repairable for one reason or another, I may
be interested in a drop in replacement for the original electronics.

I've opened up one of mine just now and extracted the PCB.  There are eight
10 microfarad axial electrolytic capacitors on it.  Each of them has some green
salty corrosion deposits on one or both of their leads while the leads on the
other components are bright and shiney.  If I had spares available, I would
try replacing these components and see if it makes a difference.  I unsoldered
them anyway in case they cause damage to the PCB.  Most of them measured ok
on the capacitance range on my multimeter but one of them reads only 3.5

Peter Coghlan.

>	paul

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