Sony KV2101 Reactivation

[Tomcomm]

My next TV reactivation will be this 21in Sony trinatron, chassis # SCC-100D. I've got it's schematic dated 1976. It's my first non-roundi, bought new and uses a 570DB22 CRT.The all wood cabinet is in excellent condition so I want to get it operational. This strange crt has only an 8 pin socket with common G1s, G2s and G4s with R-Y, G-Y and B-Y video cathode driven! The 3 guns are arranged in line horizontal. Heaters are driven from a tap on the horizontal output transformer.

The red and blue screens are plenty bright but the green is invisible with the nominal 4.8vrms heater voltage. I am now running the heaters off a variac and fil xformer. At 6.3vrms, the green screen is barely visible and at 6.8vrms
the green comes up to a very wimpy level, totally no good for color bars. The heater filaments appear slightly less bright than my other color crts. I run my 25in Magnavox at 8vrms with a booster, is this trinatron rated at 6.3vrms like other crts? Can it go to 8vrms and expect some lifetime?? Can trinatrons be rejuvenated, if so what is the procedure?

This Sony 570DB22 is listed new for $400 on Video Display Corp, so I've got to find a used one, maybe from a 21in Sony computer monitor, any suggestions?