Not Quite Sure What To Call This

[vts1134]

Originally Posted by DaveWM

Maybe just a weak CRT that the cutoff is not that sharp.

I have another 10BP4 that doesn't give me as good a picture as this one. It displays the symptom as well.

Originally Posted by DaveWM

would be interesting to see if you could see it on a scope. Need a fixed image of course and then look at each line of data (horz scan rate) compare the composite video to the output of the detector,then trace thru to the CRT grids (or cathode if that is how it goes).

I'll give this a shot, but I am still extremely green with scope interpretation.

Originally Posted by old_coot88

The problem is almost certainly in the video chain. Have you checked the peaking coils for continuity? Looks to be eight of 'em sprinkled from the detector and the CRT.
If they're all good, injecting with your B&K point by point thru the video chain (attenuating as necessary) oughta spot the problem.

The coils are all good.
Unfortunately I don't 100% trust my B&K at the moment. I think it needs some servicing of it's own for a few reasons. It's quite a shame as this is precisely what it is good for. That will be my next project on the bench.

Originally Posted by old_coot88

That sounds almost like the control is cruddy/scratchy. If you have an analog ohmeter, check to see if it runs smoothly from stop to stop without drop-outs or jumpiness.

That 's what I thought also, but it ramps smooth as silk from 0 to 10k.

I think I'm going to go resistor hunting in my video section and see what I can find.