Working on First GE Color

[old_coot88]

Originally Posted by old_tv_nut

This refers to a crystal "ringing" circuit. It actually does not oscillate on its own, but has a very high "Q" so that it produces a decaying oscillation that lasts longer than 1 horizontal line when excited by the burst. When this decaying waveform is amplified and clipped, it is sufficient to drive the demodulators.

Son of a gun. Then it doesn't use a 3.58 referance oscillator at all, right?

[NewVista]

Originally Posted by old_coot88

..it doesn't use a 3.58 reference oscillator at all, right?

Yes, in the Wallace Manual you see a Burst-Gate, then a Hi-Q Crystal Tank Circuit, then buffer/clipper-limiter to deliver subcarrier phase-locked to Burst. I knew GE did this in the sixties but, as others have pointed out, Motorola and Admiral also sometimes used this ingenius idea.

[old_coot88]

Originally Posted by NewVista

Yes, in the Wallace Manual you see a Burst-Gate, then a Hi-Q Crystal Tank Circuit, then buffer/clipper-limiter to deliver subcarrier phase-locked to Burst. I knew GE did this in the sixties but, as others have pointed out, Motorola and Admiral also sometimes used this ingenius idea.

Interesting. On a related note, in 1969 we pulled a (then) late model GE into the shop with a really bad color sync problem that couldn't be fixed in the home with tubes. Noticed an NE-2 neon bulb in the burst area of the circuit board and tried replacing that, and it fixed the problem. I don't remember the details of the circuitry as GE was not one of our store's specialty brands. But the NE-2 was involved in the burst gate circuit.
Bill(oc)