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#1
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I think the CRT lost vacuum.
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#2
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God---We hope not!
The best way to check that is to remove the horiz output tube and observe the CRT neck, to check the status of the heaters of each gun. If the CRT went to air, all three heaters would be burnt out. The set uses an all glass CRT, 21FB or 21FJ. |
#3
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Quote:
__________________
Tom C. Zenith: The quality stays in EVEN after the name falls off! What I want. --> http://www.videokarma.org/showpost.p...62&postcount=4 |
#4
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Quote:
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#5
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In some cases where the CRT has gone to air, the heaters still have continuity but will not glow because thery're immersed in a heat-conductive fluid (air). But the whole neck gets real hot real quick due to heat conduction.
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Audiokarma |
#6
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The heaters are glowing just fine in the CRT. The tube is a 2007 Hawkeye rebuild with low hours on it. The set was working just fine until this happened. I really think it is an HV problem. I will need to pull the chassis to troubleshoot it properly. I did look at the HV rectifier socket and cup. There appears to be no damage to either. The 1500 ohm resistor across the HV rectifier socket is pretty cooked. It measures 2K and looks like a ferrite bead. The body is black and none of the color bands are visible. The inside of the HV cage is fairly clean as I cleaned everything when I restored the set eleven years ago. This set has performed well while I have had it nothing beats that Zenith color and build quality. For now I will have to put my 1956 RCA 8" B&W set on top of it until I can get it fixed.
__________________
Just look at those channels whiz on by. - Fred Sanford |
#7
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My first principle of trouble shooting: fix the obvious things first. If a new resistor fixes it, you are done. If a new resistor cooks also, it will lead you to the real problem. Good luck!
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#8
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If the CRT lost vacuum you will see a blue purple glow in the neck of the tube.
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#9
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That burned resistor on the 3AT2 socket was a common problem, even when those sets were relatively new.
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