Another RCA CT-100 discovery B8001599

[dtvmcdonald]

Originally Posted by Penthode

What is appalling about the Q Channel response? It is suppose to cut off at 500kHz.

On my set both the white original coil ... which measured OK at low frequencies ... and a NOS 6 mH coil had a high frequency 3 dB point about 200 kHZ and it was way way down at 500 kHz.

I tried changing the 22 pF cap to ground to 10 pF and that upped the 3 dB frequency but resulted in a visible and actually irritating timing mismatch: the Q was too early. I experimented and found that the best overall was about a 3.3 mH peaking coil and an 18 pF plate to ground cap. This has the transition a bit early and a bit of orange line at the green to violet transition but the brightness error is about at the right spot.

In my personal opinion they really needed just a bit shorter delays for Y and I.

The only problem is the very rare violet to green transition. Green to violet is OK as is either violet or green to or from gray. See the I-Q only test pattern. IF you turn off the color entirely on this pattern you see only
the white and black areas ... the rest is constant gray.

http://www.videokarma.org/attachment...1&d=1659728707

http://www.videokarma.org/attachment...1&d=1659728096