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  #31  
Old 02-17-2017, 10:15 AM
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Yep, ringing in the horizontal yoke. Check the 56pF cap or 1K resistor hidden in the yoke.
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  #32  
Old 02-17-2017, 10:49 AM
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To avoid a possible wild goose chase, it might be worthwhile to ascertain that the bars are deflection-based, and not in the video chain. Shunt the CRT control grid to ground with a cap, which kills the video. If the bars are unaffected, they are in the deflection system. Cap value not critical, anywhere from .047 - .1 or so.
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  #33  
Old 02-17-2017, 11:30 AM
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Originally Posted by vts1134 View Post
Since this is the second time that's been mentioned, I trust my method for restuffing is such that most can't tell that I've done anything (which is half of the goal in a restoration).
What! You mean you didn't wipe all that crusty old wax off so they look like shinny NOS? How dare you.
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  #34  
Old 02-17-2017, 03:42 PM
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Originally Posted by bandersen View Post
Yep, ringing in the horizontal yoke. Check the 56pF cap or 1K resistor hidden in the yoke.
Could either of those parts also be the cause of my raster being off-center to the left and my horizontal centering control being pretty much non-functioning?


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Originally Posted by old_coot88 View Post
To avoid a possible wild goose chase, it might be worthwhile to ascertain that the bars are deflection-based, and not in the video chain. Shunt the CRT control grid to ground with a cap, which kills the video. If the bars are unaffected, they are in the deflection system. Cap value not critical, anywhere from .047 - .1 or so.
I'll give that a try tonight.
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  #35  
Old 02-17-2017, 04:28 PM
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Originally Posted by vts1134 View Post
Could either of those parts also be the cause of my raster being off-center to the left and my horizontal centering control being pretty much non-functioning?
I don't think so. The centering control works by adjusting a DC bias current through the horizontal yoke winding. Check the voltage across the centering control and see if the voltage on the wiper changes as you adjust it.
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  #36  
Old 02-19-2017, 08:21 PM
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Progress report. The horizontal centering control is broken. It stops at around 10ohm and it's supposed to be a 20 ohm control. Does anyone have a 20ohm control w/center tap and a short thumb screw shaft?



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  #37  
Old 02-19-2017, 08:32 PM
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Might be able to jump a 20 Ohm across it's terminals for a temp patch.
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  #38  
Old 02-19-2017, 09:01 PM
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Regarding the horizontal ringing, after shunting the crt control grid to ground to confirm the issue was not in the video, I replaced the 56pf capacitor in the yoke and while the black bars didn't completely disappear, they seemed to be less noticeable. Is it possible the cause can be coming from more than one place?

I also replaced the 6SN7 in the vertical oscillator and the vertical collapse didn't return after that. I'm going to keep an eye on it though as it went away and returned before.
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  #39  
Old 02-19-2017, 09:40 PM
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stuff can work together to make horizontal ringing.
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  #40  
Old 02-20-2017, 01:40 AM
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Originally Posted by vts1134 View Post
I'll take that as a very nice compliment. All of those capacitors are retuffed original shells. Since this is the second time that's been mentioned, I trust my method for restuffing is such that most can't tell that I've done anything (which is half of the goal in a restoration). The only modern capacitors that are visible in the set are the ones associated with the video amplifier/inverter that I added. I figured since that is a modern addition then it should have visible modern capacitors.
Nice!
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