One thing you can do, in XY mode, is sweep the horizontal and then the vertical centering rapidly back and forth.? With input shorted to eliminate as much interference, you *might* get an idea of the waveshape.
Another option is to take a function generator, put it on triangle, and then use it as a fake horizontal sawtooth.? If your function generator does ramps, so much the better.? It will eliminate the internal sweep generators from contention.
Another option is to disconnect the vertical and horizontal plates if possible, (it may drift because of static buildup), but that eliminates pretty much the entire vertical and horizontal chain.
Reconnect and figure out what's coming from where.
In the vertical and horizontal amplifiers, generally shorting the two complementary signal rails is not only reasonable, but eliminates the contribution from previous stages.
Just thoughts, though.
Harvey
Failing that, perhaps you should blame the local FM stations, as has been indicated in other threads.
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On 2/27/2021 7:18 PM, alan.bain@... wrote:
I have a 2465 with a very similar sounding focus problem. In X-Y mode I cannot get completely down to a point only a short horizontal line (using astig & focus controls and focus if fully ccw so output of 0V from control pot) and I'm sure I shouldn't be working at the end of travel of the focus. I cannot also get a short vertical line!
The focus output is producing between -108 and -180V and supply rails look good (have replaced a few caps).
There is a not very obvious DC restorer circuit in the grid side which had a very slowly rising voltage out of an LF353 which does appear to work as per the diagram in the manual, but part of me wonders if this could be a bad CRT since
