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  #46  
Old 01-31-2016, 09:27 AM
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Another restoration that looks awesome! What's next on the restoration bench? Possibly a porthole or a remote set?
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  #47  
Old 01-31-2016, 11:06 AM
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Nope. A Stromberg Carlson 21 inch tabletop I'm restoring for a client. I'll be starting a new thread soon.
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  #48  
Old 01-31-2016, 03:44 PM
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Excellent restoration, Bob. I'm surprised they didn't recess that tube socket 1/4" or so below the chassis.
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  #49  
Old 01-31-2016, 03:51 PM
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Yeah that would have been a simple solution. Perhaps I could drill out the rivets and recess it
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  #50  
Old 01-31-2016, 05:34 PM
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Quote:
Originally Posted by Electronic M View Post
If you put your finger in the middle of a 20KV arc and you are not connected to either supply pole you will feel more pain from the plasma burn than the shock (as I know first hand).
Tom, I'm sure you realize that with the Zenith color safety cap failures, it was because the high voltage would soar insainly high, at which point the HV could arc "through" the CRT neck glass to the yoke or convergence poles. But that's not the same thing that happens with sparks between adjacent dag islands or a grounding strap on the outside surface of a b&w CRT.

Last edited by Kevin Kuehn; 01-31-2016 at 09:41 PM. Reason: still don't know how to spell through some days
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  #51  
Old 01-31-2016, 09:03 PM
old_coot88 old_coot88 is offline
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Quote:
Originally Posted by Kevin Kuehn View Post
...But that's not the same thing that happens with sparks between adjacent dag islands or a grounding strap on the outside surface of a b&w CRT.
Right. The arcky sparkies you'd get there would be more akin to rubbin' a cat's fur vigorously. But it will generate hash that'll sure play hobb with sync.
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  #52  
Old 01-31-2016, 09:46 PM
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Quote:
Originally Posted by Kevin Kuehn View Post
Tom, I'm sure you realize that with the Zenith color safety cap failures, it was because the high voltage would soar insainly high, at which point the HV could arc "through" the CRT neck glass to the yoke or convergence poles. But that's not the same thing that happens with sparks between adjacent dag islands or a grounding strap on the outside surface of a b&w CRT.
I have a set with bad safety caps and it appears to arc over the surface of the glass, and not through it.

The other example I gave of a poor arcing ground strap connection was a surface arc too and that surface arc DID cause an implosion.
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  #53  
Old 06-23-2017, 09:47 PM
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I noticed the aquadag coating on the CRT bell was flaking off (there is a large bare spot where the coating should be, even though most of the rest of the dag is still on the tube). I'd replace the tube, as it could be very weak--especially if the TV was made in the 1950s and was used a lot by its former owner(s). There could be high-voltage issues as well if the dag coating (or any part thereof) is missing, including arcing or even no raster. Because the dag is one part of a large HV capacitor in all CRT TVs, it is very important that the coating is intact over the entire surface of the tube bell.

Edit: I just looked at some other posts in this thread and found that Bob had recoated the CRT bell, thereby restoring the tube to normal, or at least as close to normal as one can come with a 1950s-era CRT. I was not aware (until just now) that flaking aquadag could be replaced, but I learned something tonight when I saw the references to Slip-Plate and the other compound mentioned.

BTW, the picture on the newly-recoated CRT looks good from here. Bob said there were still some issues with the image the tube produces, but from what I can see, the picture is pretty darn good. I would think defects in the raster, etc. would show up more prominently on a crosshatch pattern than on a standard program picture anyway.
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Last edited by Jeffhs; 06-23-2017 at 09:59 PM.
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  #54  
Old 06-24-2017, 10:18 AM
dieseljeep dieseljeep is offline
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Quote:
Originally Posted by Jeffhs View Post
I noticed the aquadag coating on the CRT bell was flaking off (there is a large bare spot where the coating should be, even though most of the rest of the dag is still on the tube). I'd replace the tube, as it could be very weak--especially if the TV was made in the 1950s and was used a lot by its former owner(s). There could be high-voltage issues as well if the dag coating (or any part thereof) is missing, including arcing or even no raster. Because the dag is one part of a large HV capacitor in all CRT TVs, it is very important that the coating is intact over the entire surface of the tube bell.

Edit: I just looked at some other posts in this thread and found that Bob had recoated the CRT bell, thereby restoring the tube to normal, or at least as close to normal as one can come with a 1950s-era CRT. I was not aware (until just now) that flaking aquadag could be replaced, but I learned something tonight when I saw the references to Slip-Plate and the other compound mentioned.

BTW, the picture on the newly-recoated CRT looks good from here. Bob said there were still some issues with the image the tube produces, but from what I can see, the picture is pretty darn good. I would think defects in the raster, etc. would show up more prominently on a crosshatch pattern than on a standard program picture anyway.
Entries #25&31 show a different CRT, than the original one. It was one Bob had that tested good, but the a-dag coating was flaking off.
I had read somewhere that Warwick aquired Pacific Mercury sometime in the 50's. They were building the Thomas organ there as well.
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