COSMAC Elf switch panel using PCBs

Brent Hilpert hilpert at
Sat Apr 23 19:46:06 CDT 2016

I think you two are talking different versions of the Elf: Eric is talking specifically about the Elf 2000 whose circuit design has been modified considerably from the original version Dwight appears to be referring to.

For my part, when I refurbished a period homebrew implementation (someone's high school project) I relabeled the switches to indicate all 4 of the functional states of the 2 switches rather than the somewhat inexplicable "LOAD" and "RUN".

On 2016-Apr-23, at 4:09 PM, dwight wrote:

> Lf it were mine to make, it would be a spring return
> momentary SPDT. NC would be ground and NO would be +5V,
> as per the schematic.
> I'm not sure what the manual says about it.
> It is debounced with a jam latch, as per schematic.
> Tinker Dwight
> ________________________________________
> From: cctalk <cctalk-bounces at> on behalf of Eric Smith <spacewar at>
> On Sat, Apr 23, 2016 at 11:28 AM, dwight <dkelvey at> wrote:
>> I looked at the schematic pdf and it looks right.
>> The ground lead is the NC.
> It's an SPDT toggle. Neither the NC or NO pin of the switch should be
> tied to ground; it's the common pin that's grounded. So for a toggle
> switch, which side is NC and which is NO?
> Anyhow, apparently if I'd read it more carefully, it is explained in the manual.

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