On 6/20/2021 12:48 AM, adesilva_1999 via groups.io wrote:
I found the hard way that the Time base/horizontal module was the culprit. It has done some sort of damage on the interface board.
I was able to source another 465M which had a different problem on the display. It was fuzzy and was not a straight line but some funny shape which is hard to explain. Anyway, I got it knowing that it had a working main board and HV parts. Thinking that the funny display was due to the time base, I moved the time base module from my first scope to this second unit which was a bad decision as it started doing the same thing-blowing the fuse!
I was able to find yet another main board and a time base module. These two, along with the vertical module and the power supply (transformer and the heat sink etc.) from my first scope worked like a charm. I had a known good CRT to go with it and the trace looks very clean and well defined now.
Now there is another question for anyone who can help. Why would the trace blank for a split second every now and then?
Thanks for any ideas.
Might just be dirty focus or intensity pots.
Try just running them back and forth many! times with the power off.