Trapezoidal Raster

[vts1134]

Is a trapezoidal raster ever caused by anything other than a defective yoke? The only reference I can find is in my RCA pict-o-guide and it points to a shorted winding on half of the yoke. I have a set that has an ever so slight trapezoidal raster (taller on the left than the right) and I'm wondering if yoke and or focus coil positioning or something else entirely could be the culprit. I've never seen a shorted half of a yoke (technically half of a half I guess) so I don't have any real world comparison but I would think it would be worse than what I have.

[Eric H]

I would think a short would be much worse than what you have, that really doesn't look too bad to me. If it was in the cabinet and adjusted to fill the mask I doubt it would even be noticeable. geometry on old CRT sets is often somewhat iffy in any case.

[dieseljeep]

Originally Posted by Eric H

I would think a short would be much worse than what you have, that really doesn't look too bad to me. If it was in the cabinet and adjusted to fill the mask I doubt it would even be noticeable. geometry on old CRT sets is often somewhat iffy in any case.

Yoke failure is generally more extreme than that. Also a low high voltage condition.
The picture shown looks rather good.

[zeno]

I dont think its the yoke, every one Ive seen keystoned was
very bad. Look for magnets missing from yoke or if its got
"wings" with magnets bend them a little. Dont think its the centering rings either. May be just the nature of the beast....

73 Zeno

[vts1134]

I kind of figured it probably wasn't a shorted yoke, but thanks for the replies. I'm going to do some more searching before I give up on perfect geometry.