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  #16  
Old 10-08-2017, 09:56 AM
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Quote:
Originally Posted by zeno View Post
The HV cups were high failure rate on these & the 16"
cousin. Would get pin holes. Also filament windings would
arc. Fire it up with the door opened to see where its arcing.

Disassembly:
First discharge the HV several times. If the tube wont
budge it may be rusted in. Remove the separate plastic
part of the socket ( pull up) then the 2 screws holding in the socket
then the cup. Clean up & fix the arc.
Remember that all the HV & wiring is sitting as apx 22KV so
any rewire needs high breakdown wire.

73 Zeno
LFOD !
So, just to make sure, I should be able to pull out the tube without unscrewing anything?

Also, any special procedure for removing the cap thing on top of the tube? Is it attached by metal hooks like the anode cap or do I just pop it off?

Last edited by Freon; 10-08-2017 at 10:11 AM.
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  #17  
Old 10-08-2017, 10:52 AM
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HV rect Tube top cap should just lift off.

Tube should just pull out of the socket...If it is very stubborn try rocking it in a circular motion while pulling up with low to moderate force.
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  #18  
Old 10-10-2017, 02:16 PM
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I'm finally gonna be able to take that cup out and clean it, then I'll work up the courage to turn it on with the cover off and see what happens. I held off because I couldn't find an alligator clip lead to discharge the CRT, so I had to order a new one. Better than dying.

Since the original power cord is attached to the cabinet and I don't want to rip it out, can I use a standard two-prong power cord, you know, this one? It does fit, but I can only assume.
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  #19  
Old 10-10-2017, 06:38 PM
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You can use the new cord provided it fits the pins properly and isn't an intermittent connection. On the other hand, the original cord is usually attached to the back in such a way that you can remove it and use it as a "cheater" cord (without the back). "Cheater" refers to defeating the safety aspect of forcing the the power to be disconnected when you remove the back. Important for the average customer, but just a nuisance for the service tech who knows what they're doing.
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  #20  
Old 10-10-2017, 06:44 PM
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Well, Electronic M and Zeno were right on the money. The cup's got two holes on the bottom of it (but just one in practice as you'll see), and someone obviously attempted a repair.
More electrical tape under cup
One of the holes filled with black goop
Bottom of cup
Not only that, but one of the screws holding the cup to chassis is missing.
Doesn't seem like something a tech would do. I'd almost guess an enthusiast tinkered with this one not too long ago, and perhaps decided it was beyond saving... Or, more than likely, the second hole is fresh and unrepaired.
Looks like I'm gonna have to figure out how to use silicone... Or anywhere I can just buy a new one...?

Last edited by Freon; 10-10-2017 at 07:00 PM.
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  #21  
Old 10-10-2017, 07:13 PM
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Oh crap. I just broke in half the little rubber spacer where the anode cap for the horiz. output tube comes out of the HV cage... Gonna guess that was for grounding the wire? I was gonna take off the cage and clean around the area a little more, I dunno what I was thinking! I thought the two halves would snap back together, but nope. Maybe just superglue will fix it, but wouldn't it burn up if it decided to arc here?

I hope I'm freaking out over nothing but... there's so many uncertainties with these sets, especially when you're a beginner...

Last edited by Freon; 10-10-2017 at 08:04 PM.
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  #22  
Old 10-11-2017, 07:07 AM
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It's just a little rubber grommet to keep the wire from rubbing against the metal. It's not going to arc without it. Those things always break and deteriorate from age. Don't worry about it - the insulation on the wire is what's really important, that thing was just there to protect the insulation. When you do get it all back together, you can wrap something else around the wire - like a cut scrap of insulation from larger wire - to protect that rubbing point and tuck it in there and secure with zip ties.

-Ian
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  #23  
Old 10-11-2017, 11:00 AM
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Some hardware stores stock equivalent grommets...If you wish you can buy one unsolder the lead and thread it through the new one then resolder.

Those burn holes on the bottom: best to drill them out till there is no black (conductive carbon tracking) left, then fill the hole with RTV silicone. (you can buy a small tube that does not require a caulk gun at an auto parts store.) Make sure the patch is flush with the underside bottom of the cup so it will mount properly to the chassis. It does not matter if the patch domes up inside the cup. Let the silicone cure before applying power again.
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  #24  
Old 10-11-2017, 01:05 PM
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Alright, good to know... It turned out the HV cage was held to the bottom by an bent metal tab that wouldn't budge, so I gave up. Didn't look like much to clean other than the flyback plastic case which still has some gunk on it.

On the other hand, I DID find and purchase a NOS replacement cup (Workman HVS-14) which ended up being cheaper than buying a drill + silicone. And I'll get one more screw to hold the cup in at ACE Hardware, assuming the NOS cup doesn't come with screws.
Almost done, then! Let's hope this will be the fix...

Last edited by Freon; 10-11-2017 at 01:22 PM.
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  #25  
Old 10-14-2017, 03:07 PM
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HAHAHAHHAHA! YEEESS!!! IT'S ALIIIIIIIIVE!!!!!




Album link!

AAAAAAaahhhh I'm so freaking overjoyed! I can't believe it! Thank you, THANK YOU Videokarma!!!! One more American crafted master work of engineering saved from destruction!
All tubes seem to be lighting up, even that damaged looking 6U10.

Now, a quick glance of those pics will tell you there's still work to be done. Most obviously, it's incredibly blurry. (I know this is a low voltage focus set, but it's really an abnormal level.) There's a slight purple tint (that clears up a bit the longer it's on) and retrace lines are visible. A TON of pot adjustments are in order. I'll take the opportunity to ask, what is the general procedure for re-adjusting a set like this? What should I do first and last? Will the SAMS Photofact 1067-2 (which I can't find anywhere) be of any help here?

Here's a quick quiet video of my baby in action. The screen has a tendency to wobble like Jello, and there is a slow horizontal wave of sorts moving from the bottom to top. That could be almost anything, but aged capacitors are likely. I am using my Sega Genesis as a makeshift pattern generator with a custom ROM, by the way.

Quick update: I'm already seeing picture improvement just by leaving the set on. No more Jello wobble. The retrace lines are coming in and out and it's getting gradually sharper. Mr. Zenith appears to still be waking up from his long slumber.

Last edited by Freon; 10-14-2017 at 03:52 PM.
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  #26  
Old 10-14-2017, 03:50 PM
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First off reduce brightness till the blacks are not lighting the screen or are to the minimum amount perceptible. The dimmer the pic settings the longer the CRT eill live and often the better the focus. Second adjust the fine tuning knob (outer ring of the VHF channel knob for best compromise of detail, sound and color). Some sets you need to push in and turn the knob to engage the gearing....The fine tune should go from static to monochrome pic to normal pic to pic with color squigelies back to statis through it's range...If you can't hit static in both directions then something is wrong. lack of correct fine tune can look like a focus issue...

If it is a focus issue look at the focus adjustments available and see if changing them will have an effect. IIRC this one adjusts focus by swapping which terminal the focus wire goes to. Focus can change with HV level if good focus not achievable, suspect wrong HV setting.


The set may benefit from Grayscale, purity and convergence adjustments. (all searchable here, and should be covered in sam's too). Get focus, sweep size, centering and linearity right before messing with purity or convergence (they interact).
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  #27  
Old 10-14-2017, 04:29 PM
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Fine tuning works as intended. I got rid of the purple tint by turning up green G2.

I cannot get it to show total blackness, i.e. the picture is washed out and hence the retrace lines. I probably need to bring the master G2 down. Which, on this set, is just the HV level control, right? The picture is MUCH sharper during the first few seconds of screen on time, then blurrifies shortly after, so I think it's HV related. Too high? I wish I had a high-voltage probe, but I will have to eyeball it...
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  #28  
Old 10-14-2017, 04:32 PM
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The master HV control has nothing to do with the G2...If you don't have an HV probe don't touch it.

There is a brightness range pot wired to the brightness pot that you may wish to adjust.
The greyscale adjustment may also be worth doing (and a better move) to shift brightness level/remove tint from monochrome picture. To do greyscale with no signal input, turn brightness to min, flip service switch to service position (vertical will collapse), turn all G2 controls to min quickly (screen should be totally dark*), turn red up until line just becomes visible increase green till the two mix in proportion to give pure yellow, turn blue up to get pure white, flip service switch to 'normal' turn brightness up for normal picture, with monochrome image check that blacks are not tinted and whites are not tinted, if black is tinted start again, if black is good but white is tinted tweak individual colors of video drive controls, and recheck. When monochrome is not tinted your done with greyscale.

*If one or more guns won't extinguish turn sub bright and or video drive for that color down till it will at min G2 setting.


If only a portion of the screen is tinted on what should be an all white screen, or an all red, all blue or all green screen your sets purity is off and or the shadow mask is magnetized. Demagnetize (degauss) it and preform the purity adjustment proceedure.
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Last edited by Electronic M; 10-14-2017 at 04:48 PM.
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  #29  
Old 10-14-2017, 04:34 PM
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Got it. That could've been bad. Well other than that I don't see any master G2 control, only the individual color ones.

Last edited by Freon; 10-14-2017 at 04:38 PM.
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  #30  
Old 10-14-2017, 04:50 PM
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I edited above.
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