Hitachi V-1565 scope in X-Y mode, X axis problem

[NightMoth]

Hello all

I'm trying to draw some geometric figures on my Hitachi V-1565 scope in X-Y mode,
and I always get figures shrinked along X axis.

For rhombus expected X = 2V, but real is 1.2V



For square expected X = 3.8V, but real is 1.1V



Y seems always OK.

div for two channels are the same, other settings according to user manual.


Am I wrong with my expectations for figures sizes? or it is problem with my scope?

[BrokenYugo]

Photo angle makes it hard to tell but it looks like the inner knobs of the volts/div knobs are not in the same position, both should be clicked into the "Cal" position if you expect the graticule to read out correctly.

[NightMoth]

Photo angle makes it hard to tell but it looks like the inner knobs of the volts/div knobs are not in the same position, both should be clicked into the "Cal" position if you expect the graticule to read out correctly.

Thank you for reply! I re-checked inner knobs, both in the "Cal" position... it looks like it is indeed bug in my scope, maybe because it is too old

[GLouie]

What happens if you choose channel 1 for Y axis and channel 2 for X axis?

[NightMoth]

What happens if you choose channel 1 for Y axis and channel 2 for X axis?

Thank you for reply

Your suggestion led me to find where is the cause of my problem.

When I was changing Ch1 to Ch2 for X axis by switching "Trigger source" knob, I found that physicaly applying some force to the knob in clockwise direction AFTER it set into selected position, makes Image on the screen to be correct.

 
If I stop ap[lying extra force, image on the screen become shrinked again.


This works for Ch2 and for Ch1 position as well.

As for me, now it looks like there is hardware problem in "Trigger source" knob.

[GLouie]

Yes, you seem to have dirty switches. The easiest thing to try is to simply exercise the switches by turning them through their positions many times.

It is much harder to disassemble the scope and attempt to get a switch cleaner fluid into the switch. I have not done this on my V665, so do not know how difficult this is.