Quote:
Originally Posted by UberVacTuber
The ion trap is causing the shadowing. When I move it to a point where I get the maximum brightness, that's when the shadow is the worst. When I move the trap to a position that completely eliminates the shadow, the picture dims a fair amount. Are you saying that this is indicative of a high-voltage issue?
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Nope! Now, I've put my foot in my mouth, as I misunderstood your discription.
Reduced sweep at high brightness is often associated with incorrect high voltage regulation, although blooming is a more common result. Any power tube drawing higher current than it should could shift the focus coil current or cut your width by pulling down the "B" voltage. This failure mode usually leaves the edges more-or-less straight when the image reduces, not curved like the neck of your tube.
Lets first tackle the neck shadow issue.
Generally (curved) neck shadow issues are yoke/focus coil/ion trap issues.
First adjust the ion trap for maximum brightness and refocus.
Is your focus adjustment at the end of it's range as that may be a clue?
With ion trap in the new brightest position, try repositioning the yoke and focus coil to reduce the curved shadow. (Mark both exact positions prior to moving and do the yoke first.)
If this helps, then tweak the ion trap again for max brightness.
These adjustments sometimes shift when the set is transported, or sometimes have been shifted by a prior repairman to fix an unrelated problem.
Quote:
Originally Posted by UberVacTuber
Originally I had too much width and the control had no effect. It turns out the damper resistor had failed and once replaced, the raster was the correct size and the controls then had good range. All the tubes in the cage check out good.
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Are you talking about the multi-tapped 50 watt R435 on the Ryder schematic?
If not which one?
Since you recapped, did you replace the .5mfd off of your width control with a .47mfd? It is a small change, but it could have pushed the width coil beyond its limit.
Have you adjusted the horizontal drive?
Jas.