Re: Tektronix 2465A noise on readout


Tom Lee
 

Great job, Gregor! Persistence wins again. Glad you restored that nice scope!

-- Cheers,
Tom

--
Prof. Thomas H. Lee
Allen Ctr., Rm. 205
350 Jane Stanford Way
Stanford University
Stanford, CA 94305-4070
http://www-smirc.stanford.edu

On 10/12/2020 13:52, Gregor via groups.io wrote:
I fixed it! Now it's working fine.
And of course, I'll tell you how.
After the last test, I was pretty confident that the problem lies in the HV power supply. So I continued searching for the error there. After carefully probing around in the HV supply, I found that the focus voltage (measured on C1813) had a big ripple on it. Here is the image of the voltage on C1813: https://groups.io/g/TekScopes/photo/254966/1
Then I desoldered C1813 and checked it, and I found that it was definitely broken.
Image of desoldered C1813: https://groups.io/g/TekScopes/photo/254966/2
I replaced it as you can see in the following picture: https://groups.io/g/TekScopes/photo/254966/4
And look at the next picture: https://groups.io/g/TekScopes/photo/254966/3

Now it has a perfectly sharp trace and readouts without any noise! I am super happy now :). So finally I can enjoy my 2465A.
Its always a great feeling getting something to work again.
And of course, thanks for all of your suggestions and support! I appreciate it very much :)

-Gregor



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