Hi all,
After plugging in a jigsaw / vacuum cleaner into the same outlet as my oscilloscope, things were never the same.
My oscilloscope now has a chopped line on it's display.
It seems to be that the CRT only lights up at 60 Hz (or some harmonic of it).This problem becomes more obvious the higher the time/div. If I measure high frequency signals, this isn't very noticeable.
When I put the oscilloscope on line trigger, the dotted line stabilizes.
It seems that my Horizontal circuit works fine (I can change time/div and it works properly)
It seems that my Vertical circuit works fine (I can change amplitude and it works properly)
I don't have much experience with CRT displays, so I'm asking for help.
Here is the schematic to my scope, I have been looking at V-222 sections
https://xdevs.com/doc/Hitachi/Hitachi_V212_Oscilloscope_Service_Manual-Hitachi_V212_Service_Manual.pdfHas anyone had a similar problem before?
Where should I start probing to debug?I think my heater/filament circuit may be at fault? Or maybe it is my Horizontal circuit? Perhaps some rectifier is not working properly so I get this 60 Hz choppiness?
Please see attached images