tty and video displays

[Jules Richardson]

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.

cheers

Jules