Hullo Designers and fixers !
Returning to logic design after decades of absence, I want to present an Or-gate function at the Keyboard socket of the Personal computor (IBM Design but one of 100's of manufacturers). Easy, i thought = just insert a diode type 1n916 and the Or function can be realised -- you might think.
But it doesn't work and scoping it, I am 90 % sure its because such an Or-gate needs a pull down resistor.
However, I do not know the exact type of logic used, inside this now highly compacted "Black Box" called a PC !
I was just going to inset a 100,000 ohm resistor, when i realised if i got that wrong, I could blow up the front end of which ever PC I was using !
and unlike our early days in Computing (the noble 50's and 60's) when we would actually take equipement to pieces, find the blown transistor and replace it, I would have to throw my computor away or only drive it from the Mouse ! ? !
So all i can be sure of, is that my resistor would go to deck, that is Nought volts, but reading your locid discussions, I estimate someone could given me an "exact" figure for such a resistor and save me from ruining several fully working computors..
