Tube Television Tennis

Two of them now!

It's a little wonky but I haven't filtered the B+ supplies from the various sections. The two objects are completely independent but I wired the controls together to see how well they track each other. So far the left one (the original) is slower than the right one. This is because of small differences in the components used, including the tubes. 

I measured the current consumed on the B+ rail. At 82V it drew 44mA. That's about 3.6W. Remember however the voltage regulator dissipates power and so do the filaments on the tubes. There's about 100V across the regulation tube so it's throwing out  4.4W and getting quite hot. In fact the tube I was using (a 6GV8 triode/pentode) was getting a little too hot so I wired in a separate pentode (6CM5, a common Australian horizontal output tube) in place of it, keeping the triode in circuit.

The filaments draw 3.75A, excluding the regulator filaments which have their own supply. The voltage is 8.2V, higher than what I'd like it to be. The transformer has taps on it for different line voltages. That makes the power consumed by the filaments 30.75W, and the overall consumption about 38.75W. Given the television chassis the mains transformer was taken out of would have taken more than 100W, I'm quietly confident the transformer won't let out any magic smoke in a hurry.

Of course, having everything attached to a chassis of some sort is much easier than mucking about with loose components. Here are some pictures:

The three tubes to the left generate horizontal and vertical sync signals and amplify the video signal. The four to the right generate an object on the screen, which can be positioned with the two pots to the right of the chassis.

There will be four objects in total: Two paddles, the ball and the playing field. The ball is logically compared to the playing field; if it falls outside the field vertically, its vertical direction is changed. If it hits a horizontal edge a point is awarded to the other player. If the ball hits a paddle, the horizontal direction of the ball is changed. The spaces that haven't been completely drilled out will be used for game logic (bistable flip-flops etc). I didn't drill them out because my drill battery went flat...

I scrounged enough working valves (barely) to get vertical sync and positioning working, just while I wait for things to come through the post. The valve count has risen to seven. This is just to prove to myself the idea will work in some way. Getting a decent picture out of the diode logic that connects everything is tricky, as can be seen by the vertical line that follows the paddle. There was much fiddling with resistor values.

So far I've got a vertical line on the screen. I've only got a few valves of the right type so I'm limited with what I can do so far. I've got 20 old Remington Rand tubes in the post (type 2033's, similar to the 6J6) so I'll make a chassis and add things to it when they turn up.

Here's a video of my as-always messy setup: