> Also disk I/O and RS-232 are bit-banged. You could easily slow that down as well. The big problem is really the CRT (and possibly other ICs in the computer

> Also disk I/O and RS-232 are bit-banged. You could easily slow that down as well. The big problem is really the CRT (and possibly other ICs in the computer that don't like the extreme slowdown). As noted below, if you went through the arduous process of replacing and retuning components to be able to slow the beam down, your phosphor coating is still too fast, and probably doesn't like having the beam passing only slowly over it. (You thought regular burn-in was bad!) However, replace the CRT with something else, like an LCD with some extra buffering circuit, and it could work. Yes, the color burst will be at a much lower frequency as well, but just demodulate color at this lower frequency, then.