EMI Shielding on Model F?

[msiegel]

I'm curious why the entire inside of the case is sprayed with black EMI shielding paint... was it just easier to manufacture that way?

The Model F switch assembly is a sandwich between two grounded steel plates, so *it* should already be well shielded, right?

By comparison, the Model M has no EMI shielding at all, if I'm remembering correctly.
:)

[ak_nala]

IIRC, back in the good ol' days, when personal computers were new and shiny (and mostly Apple, Atari and Commodore :-), the original FCC regs for home computer equipment mandated that there be no, nada, zilch emissions of any kind from the case. This resulted in some truly impressive over-engineering in computer cases and keyboards (which have there own processors inside, after all) with mega-shielding throughout.

These regs were relaxed after a few years (late mid-80s, IIRC) to where it simply had to not emit anything that might interfere with signals or other electronics and had to absorb anything it received without re-emitting it, which also helped in making things cheaper.

[keyb_gr]

Incidentally, PS/2 systems apparently had very low radiation levels, which made them popular with hams for packet radio and other such applications.

[msiegel]

IIRC, back in the good ol' days, when personal computers were new and shiny (and mostly Apple, Atari and Commodore :-), the original FCC regs for home computer equipment mandated that there be no, nada, zilch emissions of any kind from the case. This resulted in some truly impressive over-engineering in computer cases and keyboards (which have there own processors inside, after all) with mega-shielding throughout.

These regs were relaxed after a few years (late mid-80s, IIRC) to where it simply had to not emit anything that might interfere with signals or other electronics and had to absorb anything it received without re-emitting it, which also helped in making things cheaper.

ahh, that makes sense