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-   Early Color Television (http://www.videokarma.org/forumdisplay.php?f=36)
-   -   CTC 10 HV affected by brightness (http://www.videokarma.org/showthread.php?t=276297)

zeno 03-06-2024 10:39 AM

A few things. First this set will never be bright ! Thats normal, most watched them with little or no room lighting. Trying to make it brite will cause trouble.
Ignore the color problem for now, turn it off & make it a good B&W for now.
Do a set-up next by the book. G-2's, kine bias, HV, hoz efficiency etc.

TUBES. Dont assume NOS are new & good. Many shops saved weak ones
as test tubes. Find a dealer that looks at them first. Dont trust tube
checkers ! They dont run the tubes under normal conditions.

enuf fer now
73 Zeno:smoke:
LFOD !

Username1 03-06-2024 11:03 PM

.

So you said that when you turn up the brightness as the picture blooms it jumps around.
Does it begin to loose horiz. hold? (this was a few pages back) Or does it seem to loose
Vert. & Horiz. hold?? Anyway, This blooming is a symptom of a bad HV Rectifier tube,
So I hope you have more than one 3A3, and you can try more than one......
Same for Horiz. Output tube..... I guess you have by now got a schematic from
Early Television website.... Can you check the voltages at the power supply 360V
Source, 250V Source, 270V Source both when brightness is up, and when the
screen is dark, and report voltages under both conditions. Also, V12 6DQ5 Horiz
output tube, Can you report voltage at pin 1-5 G1 should be -40V &
Pins 4-8 Should be 130V, Also 6CG7 Horiz Osc. Can you report
voltage at pin 6, Should be 140V. Report these voltages at both
High Brightness, & Blanked or Dark Screen.... Also, the color
killer should not have any effect on weak color......

Did you replace all the capacitors in this tv?

This morning, I'm thinking your statement "it jumps around" did not
mean the picture jumps around, or the tv itself jumps around, but
it means the HV jumps around as things change on the screen..
Yes, this sounds more like it..... But I'm still interested in
the other points about voltage readings....

Thanks, & Good Morning!



.

Electronic M 03-07-2024 08:55 PM

If it's a sync jump it could be that AGC is set incorrectly and the change in brightness/contrast may be overloading the sync separator.


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