crt heater filiment weld

[Electronic M]

I don't think it is safe to try welding a single heater of a multiple heater CRT at a meaningful weld voltage... On black and white CRTs one could put a capacitor charged to 200V (which would not hold enough charge to burn out the heater once it welded) across the heater pins....But you can't do that on a color CRT since the heaters are wired in parallel, and would discharge the cap the instant it is connected, and a constant HV supply would burn out the two good filaments.

The best thing I can think of is to supply the heaters voltage through a variable DC supply, and slowly increase the heater voltage to around 8-18Vdc (as much as you are comfortable applying*) before hitting the neck. The heaters can only take so much over voltage for so long, and AC strains the heaters more....Also you CAN'T weld WITH AC.
*More is better, but too much will burn out the other heaters.