Other uses for old TVs

[Rob]

David,

That sounds like a very nifty display idea! I did something similar to a 14" B&W Sparton chassis that I had when I was in grade 8. I rotated the yoke on the CRT so that the vertical sawtooth became the horizontal timebase. I mounted an outboard yoke to satisfy the requirement of the horizontal output circuit to have an inductor to still operate and provide HV for the CRT, and used the newly disconnected horizontal windings of the yoke on the CRT to provide vertical sweep. I used the loudspeaker pre-amp as the vertical deflection amplifier (6AV6?) and ran an input jack to the high side of the set's volume control, disconnecting the feed from the FM detector. The output of the audio transformer was disconnected from the speaker and hooked to the H. windings of the yoke. Voila... big screen audio oscilloscope! You sure are right about the trace being bright! I never did burn any phosphor though. I was playing guitar in a garage band at the time (also built my own tube guitar amp, P-P 6L6's) and we used my o-scope on the set when we were playing as a visual effect along with our home-made rotating disc stobelight.

I had ideas about doing along the same lines with a color TV chassis and having a whole bank of 6SN7 based multivibrators (which I was fascinated with at the time and breadboarding) as pattern generators to mix into the input and brightness circuits, but never got beyond the drawing stage. It was impossible for me to come up with a color TV chassis at that time of my life 1968'ish. People were buying their first color TV's in my Vancouver neighborhood in 1968, not throwing them away. Canada went to limited color broadcasting (testing) in 1966 and some networks, notably the CBC adopted it in 1967.

Rob