Thank goodness for newly manufactured versions of vintage CT-100 parts.
The last of my three RCA vertical convergence transformers (part number 1104314-1) failed. One is used in a CTC-2, the CT-100 chassis. It is mounted on the rear of the high-voltage cage.
I performed a full convergence on the set four days ago, and the newly manufactured vertical convergence transformer is doing a fine job. The procedure improved convergence dramatically and, while not absolutely perfect of course, I am very pleased with the overall 15GP22 image.
Here are the two minor gremlins: On the far right of the screen the three beams diverge: blue sloping downward and green up. On the top of the screen there is a linear displacement of the red beam that puts it below the properly converged blue and green beams. After you move back about four feet from the screen, these pesky anomalies are unseen with normal eyesight -- if/when program content exposes the flaw.
A minor inconvenience is the weather. This 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.
With the remnants of a hurricane passing through here recently, there's been a lot of rain -- the grass is so green it looks fake. So what better time to again check H-V under these extended high-humidity conditions.
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, there was some mild audible 'frying' and then the H-V settled at a slightly low 17.5 kV, but in a few minutes it was back up to 19.5 kV.
I believe the culprit is leakage from the flange; last year after restoration I had to remove and clean the CRT and rubber insulator that wraps around the flange to arrest the same frying/leakage.
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 this satisfactory alignment.