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Chuck Williams
Chuck Williams, Technician
Category: TV
Satisfied Customers: 3810
Experience:  Over 25 years of experience servicing AV electronics to component level, ISF and THX Cert.
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TV picture flashes on and off. Problem began gradually; stopping

Resolved Question:

TV picture flashes on and off. Problem began gradually; stopping after the TV had been on for about 5 min. Time for picture to stabilize gradually increased. Now is present constantly and on all channels. Problem exists when receiving through cable box as well as when playing a DVD. Need to know if repair is economically advisable or if it is time to upgrade to HDTV.
Submitted: 6 years ago.
Category: TV
Expert:  Chuck Williams replied 6 years ago.



What's the model number of the TV? It will begin witha "K".



Customer: replied 6 years ago.

Model Number is: KV-32S42

Serial Number is:(NNN) NNN-NNNN/p>

Expert:  Chuck Williams replied 6 years ago.
OK, I think what you may have is your picture tube is right on the edge of working with the set's AKB, or auto cathode balance. All Sony tube TV's use AKB.


AKB is a circuit that attempts to compensate for aging of the picture tube (among other things), and if the tube isn't conducting enough (due to age), it will intermittently blank the screen or, in sever cases, not allow the picture to come on at all.


But if you are comfortable taking the back off of the set and making a minor adjustment, you can probably restore the picture for a while longer.


Take the back off, turn the set on to a blank channel (receiving snow). You will see a large gizmo with a thick red wire coming out of it going up to the glass on the picture tube. That's the high voltage (a.k.a. flyback) transformer.


On this transformer will be a small knob labeled "Screen." If I'm right, if you turn this control ever-so-slightly counterclockwise, the screen will blank off immediately. But if you turn it just a bit clockwise, it may fix your problem. Don't go too far with this control, just enough to make it work.


Try that, let me know if you have any other questions, and thanks for using JustAnswer!



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