Nice clean new-looking seleniums there, and may I add a nice clean chassis overall! Are those seleniums new? I've never had to change any on a CTC-2. On the subject of reproduced CT-100 stuff, has anyone made focus and convergence pots? I've had a couple of them with open convergence pots, and one with an arcing focus pot.

Charles

Those selenium diodes are there for looks only; while I have not had a pair fail either, for safety they were replaced electrically with a couple of 1N4005’s.

As you know, the failure of a vertical convergence transformer is particularly insidious because a common failure mode causes a chain reaction that burns out the focus pot. Too much focus current is drawn if the secondary shorts to ground; the 1X2B focus rectifier plate goes cherry, and the pot can literally blister on the outside and melt internally.

While its design voltage rating is unknown to me, the focus pot is the center of a three-element voltage divider with nearly 4 kV at the wiper. While I haven’t had to do it yet, I’ve seen an ordinary linear taper pot successfully substituted for the original one. Personally, if I have to do that someday, I’ll make sure there’s an insulated knob on the shaft before I adjust it. :yes:

I had a pleasant surprise when the chassis came out of the cabinet. Notice in the picture the hue control -- the variable cap on the end of the center shaft of the three running back from the front panel. It's in the dead-center position. Exactly where it was after aligning the chrome AFC a year ago.

UPDATE to "The value of remanufacturing vintage parts..."
 

Finally got to perform a full convergence on the set two days ago, and the newly manufactured vertical convergence transformer is doing a fine job. The procedure improved convergence to the point where the overall 15GP22 image -- to use the vernacular of the streets -- looks sharp as a gnat's ass. :D

A minor inconvenience is the weather. Yesterday is the second time in recent history that a spell of humid weather affected the high voltage. Not certain where the damn humidity planted the unwanted load, but it's highly unlikely that the new transformer is a factor. The last time this happened was a week after replacing the transformer. A three-week hiatus with no power applied to the set brought it back: the high voltage recovered after the weather turned dry.

Re the low H-V problem...
 

What with the remnants of the hurricane passing through here recently, there's been so much rain the grass is so green it looks fake. So what better time to again check H-V under extended high-humidity conditions.

Last night I did it a little differently. With a 115-Vac line I pulled open the H-V lead then applied power. The H-V swung right up to 21 kV (about right for a CT-100 unloaded H-V supply) and stayed there.

Plugged the CRT back in and powered up again. Sure enough, after some mild frying the H-V settled at a slightly low 17.5 kV, but in a few minutes was back up to 19.5 kV.

I believe in my case the culprit is leakage from the flange; last year after restoration I had to remove and cleane the CRT and rubber insulator around the flange to arrest the same frying/leakage.

If you have to you have to. But not looking forward to pulling the CRT for another cleaning. Not so much for the work involved, but I don't like potentially messing up a satisfactory alignment. :thumbsdn:

I have run into humidity problems BIGTIME while working on TVs along the coast here in CA. That ocean humidity not only is wet, it's corrosive. It leaves a sticky white film on everything. The best solution, which I have done many times for customers, is to put a computer fan blowing across a small light bulb inside the cabinet 24 hrs/day. It works! The Mitsubishi big screens get very unhappy in the ocean breeze, and the arcing almost always gouges a channel in the glass from the anode holes to the nearest ground, ruining the CRTs :thumbsdn:

In the case of a CT-100, you could turn the bulb & fan on the day before you plan to run the set.

Charles

How close o the ocean are you? Or to rephrase the question, how far from the ocean do you have to be in Southern California before this isn't a problem?

David

The light bulb/Fan trick basically raises the temp high enough to reduce condensate from forming on surfaces inside the TV. Another approach would be to place a tray of silica gel or drierite (CaSO4) inside the set for a day or so.

I'm 5 miles for the Ocean in San Diego. Even at this distance I'm careful about exposed high voltage anodes outside when the humidity > 60%. Of course, warm humid days and cool nights often leaves the air saturated causing dew to form on cooler surfaces - hence the possibility of arcing.

Humidity and what to do next...
 

For three days now the set has been working w/o H-V problems, but if/when it happens to lose adequate H-V due to weather/humidity again, I'll remount the CRT without the mu metal shield and H-V insulating wrap. Should help pinpoint just where the short is taking place.

Two or three times a year I get to climb up on the roof after a major storm and reorient my $10 antenna towards NYC again, like yesterday. See photo.

My humidity problem comes from the lake across the street, which runs three blocks down to the Atlantic ocean, which is of course the real culprit.

Hey Pete,

Certainly looks like state of the art equipment. I hope you're not using a $10.00 ladder to get up there. My brother swore he would kill me the next time I climbed on the roof to fool with an antenna. So either way there is risk involved.
Be careful.

-Steve D.

You're right Steve, we seasoned guys have to step smart.

As Pierre Salinger quipped years ago, when quizzed by a reporter who asked if he were safe skating on a frozen pond:" I may be plucky, but I'm not stupid."

Actually, I had to crop the bejesus out of that cell picture to get it to load up into AudioKarma's guts (my access to Photoshop is temporarily down).

The full frame shows a flat roof. Plus there's an easy-access hatch from the third floor ceiling, with a built-in wall ladder. My son was up there too to keep an eye on the old man. :yes:

[Fodder for conspiracy theory threads. Much later, Salinger, press secretary to presidents Kennedy and Johnson, got into hot water in '96 for publicly arguing that it was not a 'spark' in a fuel tank that brought down TWA flight 800... ]