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  #16  
Old 07-31-2017, 10:09 AM
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Findm-Keepm Findm-Keepm is offline
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Quote:
Originally Posted by mrjukebox160 View Post
Bad CRT. Broken pin in CRT seal.
The area looks external to the CRT - possible conductive white RTV sealant. Sony and others used it for isolation of the focus pin, but the RTV gets dirty with dust over time and the combination of HV and dust leads to problems. Sony had the tech take off the RTV coating between the plastic CRT base and the CRT, and use their part-numbered RTV sealant. We used RTV3145 or GC's Silicone Sealant for Electronics with 100% success.

http://knobsandpots.com/images/TVP0557.pdf

I'd get rid of the White and black sealant in the areas pointed at.
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Last edited by Findm-Keepm; 09-29-2017 at 07:39 PM.
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  #17  
Old 07-31-2017, 02:23 PM
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andy andy is offline
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It's unlikely, but it's possible that another problem such as an internal short in the CRT, or a bad flyback could be causing excessive voltage on that CRT pin. Try running it with the CRT socket unplugged to see if it still arcs on either the socket, or the end of the CRT.
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  #18  
Old 08-01-2017, 08:59 AM
zeno zeno is offline
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Quote:
Originally Posted by andy View Post
It's unlikely, but it's possible that another problem such as an internal short in the CRT, or a bad flyback could be causing excessive voltage on that CRT pin. Try running it with the CRT socket unplugged to see if it still arcs on either the socket, or the end of the CRT.
Exactly..........
Could also be the spark gap in the CRT socket
All pins will have spark gaps almost always built into the socket.
Sometimes they are separate little rectangles with a slice
in them. Usually fail from too much focus voltage ( FBT ).

73 Zeno
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  #19  
Old 08-02-2017, 09:06 PM
CPQ5360 CPQ5360 is offline
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I removed the circuit board from the neck of the TV - no arcing on the socket. No improvement with the board re-seated (in case there was any build-up of oxidation). There is no silicone or anything there that could have become conductive.

Upon observing the CRT again, the arcing appears to be just inside the glass. But I assume that isn't possible without air in the tube, so I'm guessing that the lead has broken just outside the glass, and the CRT is a goner.
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  #20  
Old 08-02-2017, 10:43 PM
centralradio centralradio is offline
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I remember back in the early 1980's I looked at my neighbors 1970's 12 inch Zenith portable was arcing inside the CRT which turned out the CRT went to air.
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  #21  
Old 08-02-2017, 10:44 PM
CPQ5360 CPQ5360 is offline
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Oh interesting. And it was still showing some sort of a picture at the time?
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  #22  
Old 08-04-2017, 06:17 AM
kvflyer kvflyer is offline
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Quote:
Originally Posted by CPQ5360 View Post
Oh interesting. And it was still showing some sort of a picture at the time?
Somehow, I doubt it...
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