Ours has a strange problem. The top 2" of the picture show what seems to be the two scans of the interlace are out of sync or something. When the screen is blank/black (playing just music through the TV), that area has every second line slightly lighter. When viewing a show, that area still has individual lines visible, and sometimes appears to contain an upside down part of complete image overlayed/interlaced with the normal image.

I used to even fix TV's, but that was about twenty years ago and it's all gone rusty, and I never had such a problem before. I don't want to spend too much time tinkering, because it's my mom's set, and she will worry about me making something worse or breaking it properly, so I was hoping to find an electronics enthusiast that might grok what is happening and know where I should look.


closed as off topic by Leon Heller, Olin Lathrop, Nick Alexeev, Brian Carlton, Dave Tweed Apr 29 '13 at 3:43

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  • \$\begingroup\$ What is the make and model number of the set? How old is it? \$\endgroup\$ – Dave Tweed Apr 28 '13 at 20:40
  • \$\begingroup\$ It sounds like the vertical retrace has gotten "slow" for some reason, and the video is unblanking before the beam has completely reached the top. But it would be pointless to speculate how this might be happening without some clue about the type of technology we're dealing with here. \$\endgroup\$ – Dave Tweed Apr 28 '13 at 20:43
  • \$\begingroup\$ I was thinking electrolytic cap, but a picture would be helpful. \$\endgroup\$ – jippie Apr 28 '13 at 20:54
  • \$\begingroup\$ @jippie It seems you are correct. Alfred Centauri has provided an exact picture in his answer below. \$\endgroup\$ – ProfK Apr 29 '13 at 6:29

sometimes appears to contain an upside down part of complete image overlayed/interlaced with the normal image.

As I recall, from my previous life as a TV repairman, that's called vertical foldover.

enter image description here

Chances are good that the problem is due to a failed or failing electrolytic capacitor as in, for example, here.

  • \$\begingroup\$ Your picture shows exactly what I am seeing, and @jippie also suggested a failed cap in his comment on the question. \$\endgroup\$ – ProfK Apr 29 '13 at 6:31

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