I`m repairing an old Hung Chang 5502 scope, it had some problems, arcs, just the half of the screen was displayed, focus and intesity don`t work, etc. I have repaired everything but I can`t make work the focus and intensity. I don`t understand how this part work, the intensity voltage comes from the left side of the schematic but this is coupled with caps so how the DC can pass through the caps to change the grid voltage??? ???
how many volts should vary the grid 4 and 5??
There is something that commonly fails in these circuits?
what test can I do to narrow the problem?
here is the full image
http://www.twin-x.com/groupdiy/albums/userpics/File0019.JPG
any Help is welcome, I have had this oscilloscope for months on my desk :-\
Rafael
how many volts should vary the grid 4 and 5??
There is something that commonly fails in these circuits?
what test can I do to narrow the problem?
here is the full image
http://www.twin-x.com/groupdiy/albums/userpics/File0019.JPG
any Help is welcome, I have had this oscilloscope for months on my desk :-\
Rafael