Problem Tube swap lightshow - worth continuing?

[deadendthrills]

I've been attempting a tube swap from an MS2930 to a fresh Panasonic (Philips) tube, and after an initial period where the convergence was (of course) way off, a buzzing is now coming from the monitor and I've been treated to this psychedelia. The circular nature of it around the screen edges has me thinking it's yoke-related but I've no idea tbh. Wondering whether to just quit now or persevere.

 

[gunblade]

did you swap the yoke?

 

[deadendthrills]

Yes.

 

[gunblade]

i would remove video signal and turn up screen pot so you can see a raster

 

[M K L]

The original Toshiba tube on the 2930 (A68KZN...) is different in that it has a high voltage divider in the neck connected to ground through pin 4 and R332. On the new tube pin 4 is not used but it might be internally connected to another pin. Lift one end of R332 and see if it makes a difference.