Expert: Cleggsan - 2/4/2009

Question
QUESTION: Zenith is picture tube HD and works fine - except the video goes completely blank intermittently (every few days). If I give the TV a soft wack in the side or back of the cabinet the picture comes back and is fine until then next time it goes out in a few days.  Should I get it repaired or buy a new TV?

ANSWER: Does the audio remain working when the picture goes out?  Does the raster remain on or does the screen go totally dark?  (Raster is 525 lines upon which the video is modulated to give the images that you see as the picture).

If the raster goes away when you lose video it is most likely an intermittency in the high voltage area.  

The video drop out may be caused by a poor connection somewhere in the set. You may be able to keep it working by just moving the set or putting a little creative torque on the chassis.  You can do this by putting a magazine or something under one corner or another and whacking the set until you find the magic touch.

It is often very difficult to find these kinds of intermittent connections - even for a trained technician. The cost of repair would depend on how many hours of labor was to be required in tracking down the gremlin;  could be a few or a few hundred dollars.  I would try to keep it going with the above mentioned methods first.  The set is old enough that any expensive repair may not be a worthy investment.

Let me know if there is more to the story.
C




---------- FOLLOW-UP ----------

QUESTION: Dear Mr. C,
In answer to your questions... 1) the audio works fine when the picture goes out; 2) the screen goes totally dark.
Not much more to the story.  TV is working fine since I gave it a wack yesterday - but who knows for how long.  I'm mystified.

Many thanks for your help!

Answer
It is the nature of intermittent connections. If you can find that magic whack and get it working then I suggest you just leave it that way.  It may go for months without any attention as long as you don't move it or bump it and knock the loose connection again.....


C