Tek T912 Intensity?


manfromtrane <ccramb@...>
 

Dear Group,
I am needing some advise on a T912 scope. I got it from an auction on
Ebay. It appears to be brand new. It had the usual problem of the
capacitor 478 shorted which drops the +120. After correcting that I
was able to get a display. The next item is that the traces are a
little wider than needed and the background of the screen has green
glow. Not as bright as when you turn on the storage but the same
contrast behind traces. I have checked all the power supplies, Astig
is funtioning, Focus is functioning and down the circuit from the
intensity and Z axis appear to be giving the right voltage and wave
forms. The high voltage supply or the CRT is making a high pitch
sound when I turn the intensity up. It quiets down when I turn it
down. If I turn the intensity clear down I should not have any trace
display but that is not the case. It dims but is still very visible.
I am thinking that High voltage must be in a runaway and is too high
and isn't being reduced enough to back off the display. I don't have
access to HV probe so that is a problem I know. Could this be a CRT
problem or something outside of it? Any help would be greatly
appreciated.

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