tty and video displays

[Brent Hilpert]

On 2020-Dec-15, at 11:15 AM, Jules Richardson via cctalk wrote:
> On 12/14/20 10:06 PM, Brent Hilpert via cctalk wrote:
>>> (It's definitely -12V, not -5V? I'm just thinking that the -12V noted
>>> on your schematic is quite close the the 15V rating on the cap -
>>> although that could explain why my later setup got caps rated to 35V,
>>> too)
>> I don't remember whether I traced it or measured it, but I'm fairy
>> confident, Vgg = -12 is pretty common for GI MOS ICs. I'll try to
>> remember to double-check it when I have the unit opened again.
> 
> Thanks! I guess I can try it first on -5V too and see if the encoder outputs do anything, and if not give -12V a go. If it works, I like the charge pump idea - I'd probably ultimately give it its own case and use it externally, so saving a wire is handy.


Just double-checked by measurement, yes, it is -12V.