That white cap is the buffer on the plate. A .001 2kv cap. I replaced with a 1600v unit and later put this NOS piece in to see if it made a difference. The centering control has been replaced by a previous person, measures 12 ohms and adjusts smoth on the screen. It looks to be good and both secondaries of the VOT to the centering pot and yoke as well.

there is a gold banded resistorcircuit of the vert multvibrator, 24k R508 and check the 2.7 meg R515. The 24k can make a big diff in vert sweep

After seeing the new pics, the linearity looks pretty decent- it just lacks height. I like the idea of replacing the cap across the vert out primary, that could cause issues. Also make sure the lin and height pots haven't drifted, if you haven't already. You're almost there!

Just a thought, are those TV shows in widescreen? You may be trying to stretch it out too far. Probably not, just thought I'd throw that out there.

This is being fed from a converter box, but the vertical is genuinely underscaned. There should be margin to spare. The 24k resistor is dead on. I did notice I replaced the .036 with a .033 so I added another ,0039 across it but it made no difference at all.

I have noticed on a schematic on boxcarcabin.com the Vert lin. control is connected to B Boost only. I'm using the Sams and the Lin cont is across 405v and Boost. Any thoughts.

Basic power supply volts are good and the lytics have been subd. I tried a different tube earlier from another set with no change.

This would be soooo much easier if I had a test jig.

Took Miniman82's advice and measured the pots.
Even though they have an affect on the screen without showing a dead spot I find the Linearity pot is open near one end!
Now whats the real value? Sams shows 100k which originally I felt was curious being one end is at 400 volts and the other end at almost 1200 volts, a lot of drop for a 1/2 watt pot. The RCA diagram shows 3.5 meg sourcing from B+Boost only. I measure aprox 5 meg before the hidden break. I also believe the replacement will need to have an insulated shaft/ rotor to prevent arc potential.

Who hazards an educated guess as to the value and where to get one. The closest I have is 3.5meg full metal jacket.

By the way I have a couple handfulls of 500k with a switch if anyone needs some. Nylon shaft.

I have one from a junk 16 chassis. My sams for the 15 and 16 show 3.4meg. My control reads 2.7meg. If you want it, PM me your address and i'll send it to you.

PM sent.

I'm now wondering if this could be the issue with other early RCA's and Clones. I came across other posts about vertical height issues or slight fold over without a real solution and was referred to as a "common problem"

Thanks again!

It's not all that uncommon, especially for high hours sets. The pots tend to have a high potential (boost) applied ot them, so they attract crud and grow whiskers faster than other ones on the chassis. And as you found out, being under more stress they fail more often.

CRT glass advise needed
 

While waiting for a part and other shop work to finish I decided to remove the cataract safety glass. On this one there was not a really hot afternoon and when a front moved through the temp droped and sky became overcast. I heared the glass "TICK" and that was it.

I have removed most of the pieces and I'm down to the last pieces near the center. The PVA is thinner at the center and there is less 'give'. I'm using single edge razor blades as shims at this point and the going is painfully slow.
I'm hesitant to use a hair dryer to help heat it up as most of the face of the CRT is now exposed. There are a few observations I've made.

• Separations showing as an arc break off quite soon
• Separations as showing like fingers result as larger chunks
• The closer to the center the more dificult to do anything with the glass.
• This tube checks really good and had a great picture and the next time I do a cataract removal they'l have to be much worse!

I have a spare clear glass from another set to replace it with.

Any advise would be great. I'm sure that I'm not the first to have to overcome this situation.

I am not sure of the problem? did the safty glass break during the removal? is that what you refer to as "tick that was it"

if the glass broke, I would assume you simply over did it with the wedges around the edges of the glass. you need to dig out some of the pva, if its too hard to dig out for space for the wedges then you need to soak in water for a prolonged time.

After digging out the space the wedges (wood closepins) are inserted and tapped in until snug then you let the heat do the work.

as the glass begins to let go esp as the contact point begins to really get small you should release some of the pressure by pulling back on the wedges, should should make the last 2" or so not pop so violently (although I have not had it break at that point it still is scary when it lets go).

Photos...
 

When Ive done this before the wedges get loose as the separation gets closer to the center. I suspect the fail was due to a lone tight wedge when the progres stoped and possibly temperature change came into play. My method is to dig out some pva and gently tap the clothspin wedge until I sense the First tight response after the dull taps of pva intrusion. On a nice hot day the "fingers" appear and travel to the center until the final pop, glass intact.
I have most of the broken material off but the middle section is very slow going and Ive not found a sample even slightly water soluble. or paint thinner, or accetone, or brake cleaner.

The CRT with the fingers was a previous removal on another CRT. The fragment picture is the current project.

Wow... you guys get cold fronts in South Florida??? A co-worker of mine lives in your county... he makes it sound as if it's summer all year long there.

At least you had another glass. I have a few spare glasses that I picked up years ago in case of breaking one. So far, I've had to do cataract surgery three times. I've been fortunate that the cataracts were so bad, the safety glasses came right off with little or no effort.

Better!
 

Back to the project. Full vertical courtesy of a replacement control via MSTATON (THANKS THANKS THANKS) , new spare glass after a miserable removal of the original.

Now time for a complete registration and purity setup and touchup the grey scale tracking. Awaiting for a remote unit that may be a better match and were good to go.

Looks really good.. Great job Dave...

+1! That set has really come a long way from page one of the thread. Excellent work!

That looks great-your persistence really paid off!

Looks awesome, glad that pot worked for you. :)

Great result and a nice picture too! It'll look even better when you're done with the adjustments. :thmbsp:

About done !
 

Well... This by far is the most time spent, on the most problems of any restore I've ever done. Did the final setup last night and registration and gray-scale is looking pretty good.

Wish the remote part was working better. The owner found a proper unit but the freqs are way off (half, about 20kc at best) and dosnt respond to ANY attempt to change it other than the master coil.

very nice setup. :thmbsp:

Wow! I sure don't remember sets looking that good. I remember as a teenager and young adult (pun intended ;)) I cold not wait to get away from round color tubes. I thought that the new rectangular Kinescopes were the "Cat's Arse". Little did I know...

They can make excellent pictures if setup right. it also makes a big difference when feeding the signal directly into the tuner instead of picking it up 50 miles away. Some of the first rectangle color CRT's did not look as good as the roundies IMHO.

Nice setup by the way. I know you spent a lot of time on this set and turned out very nice.

Looking very nice!

The picture looks really great. Congratulations!

The DTV signal has made NTSC look better than ever!

Nice job! I recapped one of this exact same model but it is such a classy looking cabinet I put it in my mom's old house in one of her bedrooms, along with a super-clean Zenith Porthole floor model in her own bedroom. Whenever workman come to her house to fix one thing or another, they are always giving her compliments on her old TVs and asking "Does it work?" I made sure that she is to let them know that yes indeed, they do work, and terrifically. : ) I tend to keep the somewhat more dinged and dented sets at MY house! : )

roundies make as good a picture as any modern crt sets.depending on the crt and thickness of the safety glass.i personally dont care for the glass.there was one set that have a tinted glass that looked like a black matrix crt.i did like that one.your set looks great.i am happy that another great roundie was saved.