more on the philco roundie
 

Got this one a while ago, still acting up on the blue. wiggle the B-Y tube around and the blue comes on stronger (like the drive is changing).

tried tapping around on the PCB, tried messing with the drive controls, that one tube seems to be the culprit, but could just be transfering the movement thru the board. the chroma board is quite large so not well supported. It seems to be a low time set.

I did check the CRT pins, the G1 voltage seems to be the problem, I metered the voltage on the cathode and the G2 when the problem shows up, they are rock solid.

G1 comes off the plate of the CRT thru a resistor/cap so I will have to pull the chassis out and get it under a strong light. I dont think its a tube socket, but I guess it could be. Not a problem as I have some spare sockets that I can use. I am hoping I will just see a cold solder joint. I may end up replacing the resistor/cap just to be sure. Of couse the plate voltage of the B-Y tube could very well just be variing in response to the tube conducting differently so I really need to look all around that tube. I did check the pin sockets, did not seem bad, but that does not really mean anything.