Vertical hold the picture flickers, or jumps, periodically

Vertical jumping may have a vertical hold issue, horizontal may have a horizontal hold issue. Most older tv sets will have some knobs or adjustable screws for vertical and horizontal hold. Turn your set on and check for these knobs on the back of your set and adjust until your picture is in as well as you can get it

change your device cables or try to put at a pc to check if isworking your pc

Make a fist with ur hand and bang on the tv bazel frame.The tv picture flickers back or bounces back to a normal picture.The tv have a vertical or a horizontal hold ics have coldsoldering joints and requiring resoldering.If u bang on the tv bazel frame picture don't flickers back or bounces back to a normal picture.The tv have a vertical or a horizontal hold ics are dead require changes those ics chips.If u don't have all the tools.Can't do a basic soldering work or able to changes those ics chips.Shop around for tv shops for estamate and repairing prices for repairing.

When Posting, its a good idea to always give the make and model number.
But it appears you have a vertical deflection problem.
being that is works for a while consistantly I am to believe it is just bad solder around the vertical IC.
If you give the model number I will assist you as to what the vertical ic is. :)

well sounds like vertical issue take to tv shop vertical ic or bad caps

The vertical output IC has failed/Power to the vertical IC is out/ or there is bad solder on the pins of the vertical output IC.

i have the same problem?

My Wesinghouse 27" lcd hdtv jumps and vertical hold is out of control after being on 15 mins. The cable company checked the connection and it is clean. We did not damage the tv. It has been doing this since we got it. We did not get a service contract. Sometimes the screen goes black with a small rolling picture on top. Help me please. Can the maufacter still help us?
we lost all the papers when we moved.

Maybe sync separator transistor is faulty

If this set uses a picture tube then your problem may be in the vertical deflection circuit. Also an unstable power supply will cause this problem. Stargazer