Heathkit GR-53A color TV

[Ralph S]

All right, it's time for another report. The set's picture and sound reproduction are working fine with the major exceptions being: The horizontal weave previously described, a tube socket which needs replacement and some buzz in the sound on certain typical over-the-air scenes. The socket change and the sound alignment will come later, but right now I've reached the end of my rope on the hum in the deflection. It shows up in the secondary windings of the yoke and convergence transformer - being a beat between the 59.97 of the vertical deflection and 60 hz, so the movement is rather slow but considerably pronounced. On the primary side there is a .390 v p-p hum at the top of the 40 mfd cap and about .185 v p-p hum on the +390 vdc feed. The hum cannot be seen at the plate of the vert. output tube and on the feed side of the primary winding. BUT get to the secondary winding feeding the vertical yoke and it's very obvious.

I've tried slapping extra 100 mfd capacitance on both the C19 cap to the primary winding and the +390 vdc feed to the green/white lead of the secondary and R42. There is no difference by either of these additions.

What's going on here? Any positive ideas would be appreciated. Check the portion of the schematic below for the area I'm talking about.