#16
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Looks like an E-081/82/83 chassis....great sets.
Focus problems could be focus pot, CRT or tripler. Do you have an HV probe?
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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! |
#17
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Well I found the focus adjustment, put the cover back on, and it wasn't 5 seconds before the brightness went out the window. I did not adjust a single thing while the back was off the TV. Brightness and contrast have no effect.
No HV probe here. Last edited by TUD1; 08-07-2016 at 10:24 PM. |
#18
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I moved the TV around a bit and got the brightness to come back, then I adjusted the focus. The focus is maxed out and it's still fuzzy, but it's better.
About three minutes later and the brightness is dead again. Last edited by TUD1; 08-07-2016 at 10:24 PM. |
#19
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Quote:
You need a schematic, and either an oscilloscope, or a purpose made TV test pattern generator with a variable level video output to trouble shoot that.
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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 |
#20
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I would try playing with the setup switch (maybe the one at the bottom, back of chassis.)
As I recall, the 74 Sylvania I have had a similar intermittent. Right off the top of my head I can't remember the fix, but it was something easy like that.
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Bryan |
Audiokarma |
#21
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bryan is right.those sets had problems with the service switch.the brightness would fade leaving you a black screen.deoxit and that should take care of that issue.this sets takes a 523 tripler.wouldnt be a bad thing to replace this too.pretty good sets.
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#22
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That makes perfect sense. When I took it apart, I accidentally hit that switch when I put the cover back on. I'll try that.
The service switch was the problem, and now the brightness is back. The focus is still way off, even with the control maxed out. Before the focus went haywire, the control was only halfway and the picture was near perfect. I was informed that I should clean the focus pin on the CRT if it's corroded, so I'll do that tomorrow. Last edited by TUD1; 12-22-2015 at 10:48 PM. |
#23
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Yes, check the focus pin. If this is good, check the focus control and the parts associated with it. If this is good, the focus divider inside the tripler is likely bad (triplers were a common failure in these).
Regarding the chassis number, that one looks more like an E21; but, I'm pretty sure the ones in those hospital sets were E08 and I know they were a 3-board modular chassis, with a delta gun CRT.
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http://www.youtube.com/user/radiotvphononut |
#24
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Thanks for the info. Here is a picture of the TV in the very small amount of time that the converter box and the TV were working perfectly.
Last edited by TUD1; 08-07-2016 at 10:24 PM. |
#25
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Pulled this TV back out today, since I thought it would look cool on the cart I got yesterday. This set, having an inline gun, has razor sharp focus and outstanding colors. I put it up back in 2015 because it has a slight problem with the color demodulator IC. On faces, the color will sort of "roll" from pinkinsh to yellowish. I haven't noticed the problem anywhere other than on faces. Found a newspaper ad from 1974 with this model on it. I didn't really believe that it was a 74 with that inline tube, but I'm pretty sure it is now.
__________________
"If you wish to make an apple pie from scratch, you must first invent the universe." -Carl Sagan |
Audiokarma |
#26
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I think it's just an inherent trait of Sylvanias of that era. My '79 delta Superset must have had the best picture of any of my sets until the tripler blew. That was replaced, but then a solder pad fell off the focus control and I'm still trying to track one down, sigh.
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#27
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Based on what I've seen and heard, Sylvania was slightly ahead of all the others on their phosphor formulation. I've seen some 60's Sylvania sets give a super bright, super vivid picture. I think it may have had something to do with Sylvania being a big light-bulb manufacturer. Maybe they had lots of experience in phosphor development from working with fluorescent and mercury vapor lamps. I have a rebuilt Sylvania Color Bright tube, and as you can see, even it gives a very impressive picture. Here it is in my RCA CTC-40.
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#28
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That is a nice looking set.
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#29
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Thanks, I thought so too. That's why I went and dug it back out of storage. It looks really nice on that cart, too. Just wish I could find a new demodulator IC.
__________________
"If you wish to make an apple pie from scratch, you must first invent the universe." -Carl Sagan |
#30
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Quote:
Dont remember which IC but one of the IC's went disco by the mid 80's. Pissed off quite a few customers & us too. Trouble was those sets held up real good. The E08 as good as Zeniths but the Super Set 19" modular chassis suffered bad CRT's just like the consoles. When new the pix was spectacular. We mined the junk sets for the IC's but never had enuf........ 73 Zeno LFOD ! |
Audiokarma |
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