Tektronix 2465B scope trace modulation   Behoben Solved
Channel: Rolf Bucher
Date: 2018-11-13

Der entscheidend Hinweis kam von Chuck Harris aus dem TekScopes Forum.



-------------------------------------------------------I would bet that what you are seeing is the EHT oscillator's AC bleeding through into the CRT's cathode/control grid circuit.

The first place I would go is to the A9 HV section, and verify that C1972 is a nice low ESR 100uf capacitor.
The -15V supply goes into a lot of areas, including the Z-axis hybrid.  If that capacitor is bad, you will get a lot of 50ish KHz ripple on the -15V line.

You can test C1972 in place by using your Rigol scope, and measuring between P191 pin 8 and chassis ground, and looking at the 50KHz ripple.  There will be some, but it should be millivolts, not volts.
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Genau mit dem Ersatz diese Kondensators war das Problem behoben. Ohne die Hilfe von unzähligen Forumsbeiträgen wäre diese Löung nie möglich gewesen.
Chuck Harris, Tom Gardner, Roger Evans, Ásgeirsson, Sigurður (Siggi) und viele andere mehr. Für diese Unterstützung, besten Dank