Running a color chassis on the bench

[RetroHacker]

Quick question - for testing, I should be able to run a CTC-15 chassis on the bench without a yoke or picture tube, provided I pull the horizontal output tube - correct? I've heard some say that I need to also pull the horizontal oscillator, but I'm not sure. Do I need to add a resistor load to compensate for the missing tubes - if so, where? Also, don't some sets have a jumper in the yoke to kill the HV when the yoke is unplugged?

And I would imagine that the same would also apply to black and white sets - correct?

Thanks!

-Ian

[wa2ise]

Don't know about that chassis specifically, but many sets use the boosted B+ from the horizontal for other circuits, and the color demod circuits usually expect a horizontal timing pulse from the horizontal circuits. So it can find the color burst reference signal.

[kx250rider]

You're MUCH better off to get (or make up) a set of extend-O-cables to run the chassis while still hooked up, or get a good test jig with adaptors for your set.

Charles

[stromberg6]

Some earlier chassis (CTC-4,5,7 etc) specify that a load resistor of suitable resistance and wattage be used to properly "load" the power supply when working on the chassis without the horizontal section being connected to the yoke, CRT, and other components. Haven't worked on a 15. Maybe there is a similar method outlined in the service literature. Just pulling the HO tube might cause the B+ to rise to levels dangerous to other circuits.
Maybe someone else can offer a more thorough explanation. Good luck with the 15!
Kevin

[Steve McVoy]

Also, AGC probably won't work without the yoke.