Philco Debutante issues

[Zsuttle]

Hi all,
I recently finished restoring a Philco Debutante, which included replacing all of the resistors, electrolytics, networks, and all other mica, wax, and bumblebee caps. A few questions.

Someone was running the set with a 6AX4 instead of a 6DA4 as the damper, I know it's not a direct replacement, how compatible are the two? I replaced it, with a 6DA4, just to have it short out while I was adjusting the Horizontal. Not sure if it was a bad tube, or if it was the TV that killed it. It tests as shorted on every function on my TV7. New tube restored the HV.

Also, I recoated the flyback as it was missing half of the tar. Used the sensor safe sealant that everyone suggests. Worked great, but now it's buzzing with the new damper. Didn't see any arcing in the HV cage, any thoughts?

Lastly, the V lin pot was broken, but I found a 3kohm NOS philco pot, and replaced it while shunting it with 3k resistor to get the 1.5k required.