Meck XB-702 restoration

[bandersen]

I tried running the 6AL5 detector lean by adding a 4.7 ohm resistor in parallel with the filament. The results were interesting.

Here's the output of the detector feeding the grid of the video amp. A small amount of ripple is present.


Now here's the signal at the plate. It's amplified (range increase on scope), but the 60Hz was amplified much more than the video.


Now here's the output of the sync separator. Seems the 60Hz is being amplified more than the video at each stage.
Perhaps it's just that the amps have more gain at lower frequencies and even a small amount of ripple out of the detector is too much.