#16
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So the brightness control that's supposed to be 100k ohms is now about 800k, any idea where to find a replacement as it is also connected to the vert. hold and vert. linearity pots?
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#17
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Well, I tested the CRT, which produced good emissions after a long warm up from it's 50 year nap. The HV section is producing the needed 10kv for the annode, but still no raster nor indication of life. Any ideas?
Thanks, Zach |
#18
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Does it have an Ion trap on the neck of the tube? It might need adjusted.
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#19
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Quote:
20180512_195134.jpg 20180512_195138.jpg |
#20
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What is the crt number?
jr |
Audiokarma |
#21
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#22
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The tube does require an ion trap:
https://frank.pocnet.net/sheets/201/1/14NP4.pdf I have never seen one that looks like the one you pictured... guess it can't hurt to try it. jr |
#23
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It requires a single field trap and that's a double. Still might work enough to give you something, you could also try removing one of the magnets from that trap.
It's theoretically possible to damage a tube by running it with a misadjusted trap, keep the brightness control turned down about halfway while experimenting with the trap. If you get a raster adjust the trap for the maximum brightness and focus. |
#24
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Great News! After finding an ion trap suitable for the TV, I hesitantly powered the set on and hooked up my DAC hoping for the best. After adjusting the raster for maximum brightness, I then proceeded to mess with all the controls and received this picture.
20180512_215104.jpg Thanks for everyone's help with this, this has been a fun first TV repair. Now to just fix the sound problems, Vertical Compression, and reverse the yoke Thanks all, Zach |
#25
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Quick question, the image appears to be shifted downwards, making it difficult to see the bottom text, and a black bar at the top. I've checked all the resistors in the vertical Linearity circuit, replaced two but still no solution. The raster fills the screen, but TV programs do not. Any ideas where this could be stemming from?
20180514_162032.jpg (The rest of the screen is fine, my camera picks it up weird. Picture is also upside down) |
Audiokarma |
#26
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Does the yoke have positioning tabs at the rear like those shown in the Marconi TV thread? ( shiny tabs @ 11 o clock and 9 o clock position on the rear of the yoke).
http://www.videokarma.org/attachment...7&d=1526186137 Rotate the two tabs together to change position... change the distance between the two tabs to adjust the strength of the position magnet. jr |
#27
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Have you heard of Letterbox movies/TV shows? All newer HD shows are 16x9 aspect ratio and most sources convert them to 4x3 aspect ratio by letterboxing the content...It is a fact of life when trying to fit a rectangular show into a square hole these days.
__________________
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 |
#28
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Quote:
Quote:
Thanks all, Zach |
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