I did some probing and found the 410V derived from the 420V boost was only around 350V. I measure R78 and it was high - about 8K.
I replaced that and got full height even though the 410V line was still low at 380V with 8V P-P of ripple.
Unfortunately, while I was adjusting various controls the picture starting breaking up. Then I completely lost the video and sound. I still have a good raster and all the controls respond.
I've already checked the tubes and replaced a weak 3CB6. The 5J6 is a little weak too, but I couldn't find a replacement so I tried a 6J6. That didn't make any difference.
I'll fire up my 1077B and try injecting signals at various points in the RF/IF stages. I hope it's something simple.
