Beam-penetration color CRT, Tektronix DAS 912x (was Re: Nice LAB11 brochure.)

Eric Smith spacewar at
Sun May 8 23:33:32 CDT 2016

On Sun, May 8, 2016 at 9:57 AM, Pete Lancashire <pete at> wrote:
> I thought the Tektronix DAS used a custom tri-color crt, where the
> blue phosphor was replaced with yellow.

It is custom, and it is tri-color (red, green, yellow), but it's a
beam penetration CRT that is not a modified version of any normal
color CRT. There is no shadow mask, and it can only draw one color per
field, like the 1951 CBS field-sequential color television, though
that was done with a color wheel while this is done by modulating the
anode voltage (and possibly the deflection drive as well).

More information about the cctalk mailing list