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#1
01-24-2016, 10:20 PM
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RCA 21-S-510N Restoration Thread- Update
I'm putting this here for any questions I have in restoring this television, if you haven't seen my original post go here:
http://videokarma.org/showthread.php?t=266154 This being my first TV restoration I have some questions the first one is pretty basic? Can one adjust the focus coil and ion trap while the TV is turned on? I'm not sure as I wouldn't want to be exposed to the anode voltage. Also In the schematic there is a 600V 0.0012 uF paper capacitor near the horizontal oscillator tube which demands a 5% tolerance, not being able to substitute another value the only 0.0012 uF capacitor I could find that wasn't a ceramic disc was rated at 1600V. My antique radio experience says that this is ok but I just wanted to be sure. Last edited by Hcompton79; 01-31-2016 at 05:24 PM. Reason: New info 
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#2
01-24-2016, 11:56 PM
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Focus coil and ion trap adjustment with the set on is sort of mandatory to do it right. It is possible to be zapped any time a TV is on (and sometimes when it's off) if you are careless. Always work with one hand in your pocket when the set is on (it almost guarantees protection from harmful levels of electric shock).
If the CRT is metal cone don't get your hand closer than 3", beware of yoke and H output tube cap voltages while servicing those can be nastier than HV....I've personally been hit by HV and yoke voltage, and found the yoke triggered my reflexes much more violently. Voltage rating of a cap is the maximum they will take before blowing up, shorting out etc. It's always fine to select a higher voltage cap. Tolerance rating of a cap applies only to the Capacitance (in farads or micro farads) not voltage.
__________________
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
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#3
01-31-2016, 05:23 PM
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Update:
I replaced all of the paper and electrolytic capacitors and while I now have wonderful sound, I've lost the raster. I noticed that the HV rectifier was not running, so I did some checks to make sure the flyback wasn't shorted out and it wasn't. So I pulled the horizontal output tube cap off and used an insulated screwdriver grounded to chassis to try and draw a spark off the cap which I could not do, I believe this means no RF is going to this tube, correct? what should I do now?
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#4
01-31-2016, 05:27 PM
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Also, I noticed a slight blue-violet glow in some of the tubes, is this normal?
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#5
01-31-2016, 08:36 PM
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Quote:
The HV supply circuit is protected by the 4/10 amp fuse, the only one in the set. If the horiz output tube isn't getting drive, the tube will red-plate. 
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#6
01-31-2016, 10:30 PM
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Ah ha! I found the problem , I accidentally wired a 0.01 uF capacitor across the wrong leads of the horizontal output tube, we now have HV. However, the screen now lacks a full raster only the middle of the screen shows a raster and the audio has dropped out.
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#7
02-01-2016, 10:09 AM
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Quote:
First, you have to determine, what does the set do? I worked on the very same set, about six months ago. There was a laundry-list of problems. First, the volume-contrast control was bashed in. Remove the control and reassemble. Was lucky it could be repaired. Try the set again and naturally the horizontal frequency was way off, but you could tune in an image, that was a way off and reasonable sound. Then the vertical circuit needed recapping. I worked on these sets when they were faily new. The same problems as today, sixty years later.
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Linear Mode
