problem centering oscilloscope horizontal axis

[luthierwnc]

Hi Guys,

Got a stumper. I'm checking a new build and my scope is misbehaving. The waveform is only showing on the first half of the first grid on the left-hand side. There is enough of it to see that it is showing the sine wave but there isn't a horizontal adjustment on the front of the device. It reminds me of an old TV where you could move the picture side-to-side with the horizontal knob. Well, this one is slammed all the way to one side. It is a Hitachi V212 20mh oldie and has always been a little temperamental. Still, I'm not in the mood to replace it right now.

Anybody seen this before? Thanks, Skip

[Enzo]

Next to your fine sweep red knob, don;t I see a horizontal "position" control? That is your centering.

Your deflection is like a push pull amp circuit, it needs two sides working together. If one side quits, the other side will grab the trace, or if one side hangs up, the good side cannot pull hard enough to keep it sentered. I'd say your H deflection circuit has an issue.

[luthierwnc]

Thanks Enzo, sh