On one 465 I worked on, the ceramic resistor network in the HV regulation path developed a cracked lead right at the body. Sometimes it worked, sometimes it didn't. Took me forever to track that down. Might be worth a look.
Paul
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On Fri, Feb 18, 2022 at 12:28:06AM -0800, Jeff Dutky wrote:
Mark,
Thank you for the pointers. I will investigate them all. I was able to get the HV up to -1600 V for a few minutes, which was just long enough to verify that the replacement CRT was working and undamaged. I got to that point by cleaning R1427 with IPA, so it may well be that there is surface contamination providing leakage paths in the HV section. I don¡¯t want to jump to any conclusions, however, since the problem has not been remotely solved.
The investigation may take a while because I¡¯ve got other, more pressing issues that require the bench. I¡¯m happy, however, to have addressed one of the big problems with this scope (the CRT damage) though I guess I just replaced it with the HV fault.
¡ª Jeff Dutky
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Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix/Linux - We don't do windows
