Chromacolor II Color Screen Shifting

[DavGoodlin]

Originally Posted by Jon1967us

What’s the best way to clean a spark gap?

Use any electronic connector cleaner. Just get the plastic cover off the CRT socket and try tha.

Do measure the K-G1-G2 voltages and post them. Make note of changes during warm up scene changes, etc.

[zeno]

its probably a hotel set. Even looks like one. Usually there is a tag on the back
that says " no labor warranty". Model number will also reflect it MOST
of the time. IIRC E & F line sets only had coax on varactor tuner models.
Since its an E line it would have come with plug in IC's & transistors.
Pull & clean the 4 transistors on the 9-89. Do the same with the 2 IC's
on the 9-86. You can do a little pushing to see if it acts up.
Since it seems to only happen with signal I bet its on the 9-86.

73 Zeno

[Jon1967us]

Originally Posted by DavGoodlin

Use any electronic connector cleaner. Just get the plastic cover off the CRT socket and try tha.

Do measure the K-G1-G2 voltages and post them. Make note of changes during warm up scene changes, etc.

Voltage measurements: all cathodes, as specified on schematic - from 145-155v. When brightness and contrast to a lesser degree, were turned down, K voltages go up and screen was tinted green, even if that G1 is turned all the way down.

Got as far as measuring Green G1 and only got 33v. Noticed the pin was bent, and with contact wiggled loosely. The pin indeed was broken internally and bent. Bending the pin straight and inserting as far as possible seems to have made contact internally with the G1 lead.

The green cast seems to have been removed by this action, now that I can put appropriate voltage on green G1. Color doesn't shift around. Will monitor for now and see how things go.

In video capture I show greyscale and color saturation. I do vary the tint a little at one point to show the range. https://www.youtube.com/watch?v=oGT3...l=Silvertone58