General Electric 15CL100

[Tom9589]

I would be interested to hear your thoughts about GE making the Hue/Tint control a rear panel screwdriver adjust control. Is the tint stable enough that you don't need to adjust it often? Is the crystal ringing oscillator circuit that stable?

[dieseljeep]

Originally Posted by Tom9589

I would be interested to hear your thoughts about GE making the Hue/Tint control a rear panel screwdriver adjust control. Is the tint stable enough that you don't need to adjust it often? Is the crystal ringing oscillator circuit that stable?

The PortaColor has the same type circuit.
The only GE that didn't use it was a IIRC the CA model, RCA semi-clone. If that the one I'm thinking about, the original GE service manual shows the color board as RCA design, including their artwork.
The 1957 GE color set, IIRC 21CL500 with the "L" shaped chassis and three 5U4's had a compression trimmer tint control as part of the front operating controls. That one also used the Victoreen HV regulator.

[old_tv_nut]

Originally Posted by Tom9589

I would be interested to hear your thoughts about GE making the Hue/Tint control a rear panel screwdriver adjust control. Is the tint stable enough that you don't need to adjust it often? Is the crystal ringing oscillator circuit that stable?

This has been discussed elsewhere on VK, but the summary is that either PLL or ringing circuits can be designed to do an equivalent job. The GE circuits do not show any noticeable deficit in performance.

The practical reasons why the hue control should have been on the front are variations in burst phase from the broadcaster and the fact that people with normal color discrimination can have a difference in sensitivity to the red and green NTSC primaries (up to +/- 20% worst case according to an early RCA paper).