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Thread Tools | Display Modes |
#16
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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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Brian USN RET (Avionics / Cal) CET- Consumer Repair and Avionics ('88) "Capacitor Cosmetologist since '79" When fuses go to work, they quit! Last edited by Findm-Keepm; 09-29-2017 at 06:39 PM. |
#17
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Last edited by andy; 11-18-2021 at 05:04 PM. |
#18
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Quote:
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 LFOD ! |
#19
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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. |
#20
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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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Audiokarma |
#21
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Oh interesting. And it was still showing some sort of a picture at the time?
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#22
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Somehow, I doubt it...
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