Rants of a 1970's Era Repairman

[old_coot88]

Originally Posted by holmesuser01

...I have fond memories of Sylvania tube chassis with lots of overheated resistors in the Y circuitry,...

Ha. Did you get any of those hybrid Sylvanias with the 2-watt collector load resistors on the two demod transistors? The resistors were carbon comp, and ran pretty hot to begin with. Over time their phenolic casing would carbonize, creating a low resistance shunt that would run hotter and hotter till one of the transistors would pop and the other was about ready to pop. We replaced each resistor with two 2-watters in series, doubling the wattage rating (and of course replaced both transistors).

[holmesuser01]

Sorry for the long delay in replying to you...

I rarely got a hybrid Sylvania set, but one that I did get to keep, was a 19" with no color. The B/W image was perfect, though. I never got into it enough to fix it. Eventually used the CRT in another set.

I never saw any hint of color in anything we viewed on this set. Too bad, as it was a nice looking set.

[old_coot88]

Originally Posted by holmesuser01

...I rarely got a hybrid Sylvania set, but one that I did get to keep, was a 19" with no color. The B/W image was perfect, though...

I never saw any hint of color in anything we viewed on this set.

That's exactly the symptom you'd get if both demod transistors were popped. If only one was popped (the usual condition), you'd get really weird color with half the chroma information missing.