V-ramp with hole

Doing vector scan with tektronix 465b.
Patching H ramp in x, V ramp in y, camera luma in z.
Problem : there s “hole” in V ramp

i ve change cable, invert the x and y. always the same pb.
i ve checked the v ramp on the oscilloscope. there s hole

on the crt it looks normal

i m lost… thks for help


That’s either a problem with the z signal, or theres a nonlinearity in the ramp. Put your score in to normal mode and view just the ramp in the scope. If it’s just a normal ramp it’s something up with z. Does the blank area scroll or is it stable

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You can’t have a hole in an oscilloscope trace, but it can move very quickly from one value to another, like a square wave, although hard to see its still a solid line. So if there appears to be a hole is withe because the signal jumps very quickly from one value to another or because the z is going down to a low value at that part


it s not comming from the z input. on the second pictures i ve plugged only the y input.
Yes it s scrolling, slowly but it s scrolling

Ok, can you take a picture of just the y signal in a normal scope mode, not xy mode? That will help show how the signal is distorting

ok. i will this week end. thx

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