This set is proving to be a bit of a challenge, but I'm getting there.
First, I did some voltage checking and found none in the vertical output circuit or brightness control. Turns out I forgot to install a 1.5K resistor.
That got me a raster, but no video or sound.
Next, I fired up a B&K 1077 and injected a signal into the first IF stage. That got me sound and a very unstable, off-center picture.
More investigating turned up a dirty 12AU7 sync tube socket, a bad 6J6 and 6AG5 in the tuner.
That got a me a stable picture, good sound and a decent picture.
Just one major issue remaining. The brightness control has a strange effect in the picture. The screen is dark for the 1st half on travel. Then a narrow window of visible picture. Then it blooms out of focus and gets dim.
Seems like the grid bias voltage must be off, but they check out OK. Might also be the 10BP4 CRT. I recall it tested good back when I started this project, but I'll test it again. I'll try swapping it out with a known good one too.
