Quote:
Originally Posted by Kevin Kuehn
Try this:
1. Place a 47k resistor between pin 11(cathode) of the CRT and ground.
2. Connect a .05uf, 630v cap from pin 3 and 4(plate) of the 6K6 vertical output
to pin 11(cathode) of the CRT.
Basically you need a positive going vert deflection pulse at the CRT cathode in order to blank the picture during vertical retrace.
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Tried it, not much change, yet.
as I am suspecting, this is mainly due to the diff in the test CRT ( 8YP4) and the one the set was made for, 12LP4.
And once I do have something built to put this into and mount it safely, the lines should be gone ( I hope )
Typical operation...
12LP4
Anode voltage. 11Kv
Grid #2 voltage 250v
max circuit value,
Grid #1 circuit resistance, 1.5 max meg.
8YP4
Anode voltage. 16Kv
Grid #2 voltage 400v
Grid #1 circuit resistance, 1.5 max meg.
https://frank.pocnet.net/sheets/049/1/12LP4.pdf
https://frank.pocnet.net/sheets/049/8/8YP4.pdf
The video smearing, as someone pointed out, is most likely peaking coils, but I'm STILL WAITING on the 3 that were sent from Canada on 4/15, ( 2 @ 120 uh , 1 @ 93 uh ), I wonder if they will ever show up now...