#46
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Sometimes that can be fixed. I had a zenith color port set that arced through the bottom of the cup. My solution was to drill out the carbon arcing path then use Permatex gray silicone to fill in the hole...It worked well and was almost a free repair.
__________________
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 |
#47
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This cup though was toast. I cleaned it with every solvent but carbon is deeply incorporated into the plastic over a lot of it.
We do have a cause of death here- severe arcing over the insulator cup blackened the whole bottom of the cage and overloaded the flyback system. Last edited by Hagstar; 11-07-2016 at 05:36 PM. |
#48
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I find fixing vintage stuff there are these days that seem like weeks waiting for parts to come. This thing wanted to wake up but the old HV cup is like poison- catnip for anything that wants to arc.
I need the parts to come soon before I lose momentum. My CTC4 was on the bench a year like this. |
#49
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Quote:
RTV3145 is the best for HV applications - it's electronic grade, self wets, and cures in 6 hours or less. Navy avionics owes it's success to RTV3145 - it solved many arcing problems in F-14 (AWG9) radar power supplies, sealed chaff buckets, and I used it to cure arcing in a Conrac monitor used in the CATIIID bench that troubleshot modules. Great stuff.
__________________
Brian USN RET (Avionics / Cal) CET- Consumer Repair and Avionics ('88) "Capacitor Cosmetologist since '79" When fuses go to work, they quit! |
#50
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+2 a similar repair is still holding in a 16" Zenith color portable. There was a full metal cap behind the HV rect cup, drilled out the pinhole the arc made and plugged and coated the cup bottom with black RTV.
__________________
"When resistors increase in value, they're worthless" -Dave G |
Audiokarma |
#51
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In this case though the entire cup is baked to a light brown color with spider webs of carbon deep in the plastic. Discharge paths cover most of the area around it in the cage.
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#52
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#53
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That's awesome news! Congrat's!
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#54
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Sweet! Looks like it is only an evening of adjustments away from a good picture.
__________________
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 |
#55
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Nice!
__________________
My TV page and YouTube channel Kyocera R-661, Yamaha RX-V2200 National Panasonic SA-5800 Sansui 1000a, 1000, SAX-200, 5050, 9090DB, 881, SR-636, SC-3000, AT-20 Pioneer SX-939, ER-420, SM-B201 Motorola SK77W-2Z tube console McIntosh MC2205, C26 |
Audiokarma |
#56
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It looks like the set was fired up in a basement or garage with the copious dust I removed on it plus some moisture from a quick warm up. It had some latex paint rings characteristic of a Garage Period. My TV mentor Keith Park killed a TV once powering it up as a kid in the garage- an arc from the anode hit the cold glass.....boom.
John H. |
#57
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Odd symptom- high voltage takes 90 sec to appear at all, then over next minute or so builds but only to 21 kv. I am replacing 3.8 and 1000 ohm resistors under rectifier.
Interesting to note this was built at the factory with a rebuilt CRT. Philco got a lot of flak for this as I recall. Last edited by Hagstar; 11-19-2016 at 06:03 PM. |
#58
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Fixed high voltage issues. Just rough convergence so far but finally an okay picture My next puzzle is that the AGC doesn't work though the pot seems to measure and function normally. Only just the right fairly weak signal makes an image, it overloads at the drop of a hat.
https://www.youtube.com/watch?v=Uj-wk-OtwzE John H. Last edited by Hagstar; 11-22-2016 at 09:53 PM. |
#59
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Thankful today for this forum- our little corner of the world for our bizarre specialty.
Does anyone know WHY Philco put over 100 volts on the early transistors in my set- in a signal chain where such voltages are dangerous and not needed it seems? |
#60
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Clues appreciated on the add warmup problem here- see video notes- https://www.youtube.com/watch?v=rLD2...ature=youtu.be
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Audiokarma |
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