After a lot of testing, I can give some more insight on my problem, and I sincerely need your opinion of experts on the matter. I have replaced and tested with a working U950, a nos and tested complete a9 board and I have checked all the DI and ROI lines from pots to U950, the problem doesn't change. The AC waveform is clamped at the low end by the vz out from intensity pot and U950 vz out but grid bias even if dc restorer works in spec can't completely turn off the crt. It only works if I lower the value of one of the DC restorer resistors out of spec: r1992 is marked on the schematic as a 240k but in reality is a 390k from later 2465 serial numbers on to 2465b (you can see this on material list), if I use a 240k resistor instead of the 390k everything works fine and the crt completely dims off and I can complete cal08 with no problems. Still this is not in spec for a 2465a. It seems a crt problem at this point, have you ever seen anything like this? It seems like a leak between g1 and cathode. Can you give some advice? Should I replace the crt?
Thanks in advance
