"Cook" 10BP4 Sencore CR70

[Kevin Kuehn]

Since you're able to adjust it into the good range with 7 volts on the filament, I would not be messing around risking a rejuvenation. As miniman suggested, those CR-70's can have flaky filament supplies. I'd try putting your volt meter directly across the filament pins on the tube under test and see if you're actually getting 6.3v with the tester loaded. The real test is getting that CRT into a restored TV chassis. As long as it produces a good watchable picture, that's what really counts.