Bowing of screen on Sony Trinitron Flatscreen 17" Monitor

Thanks for the feedback Art,

Any idea what it might cost to have a service person look at it?

It is bowed up in the middle about 1/8". I don't know if that is considered alot in the monitor industry but it drives me crazy.

Tmod

Art wrote:

Monitors do not affect people's sanity Youre already crazy. :) And very bored by the sound of it.

NT

meow2222,

At least I don't go replying to a posted question with a answer of 0 content.

Tmod

snipped-for-privacy@care2.com wrote:

Silly me. See I thought the suggestion that you must be very bored to be worrying over a 3mm deflection was a constuctive hint to rethink what you were doing in life, but maybe not.

NT

It's annoying, but most monitor and TV manufacturers do not provide for N-S pincushion correction. I've seen and corrected some quite nasty cases (strangely enough- on Sonys!) by adjusting the up/down position of the yoke with rubber wedges, but this usually affects the top geometry as well, which may or may not be desirable.

Dave

Hi Dave,

Thanks for the reply.

Oddly enough it doesn't really have the bow on the top of the screen.

It seems to all be on the bottom.

So would adjusting the yoke possibly take care of the bottom bowing without affecting the top much?

Tmod

It's possible if the yoke has been badly fitted at the factory, ie, not central and drooping slightly, to lift it a little and affect the bottom with only minimal affect on the top. It depends on the individual case. It's not a job I'd recommend if you're not electronically minded or experienced with CRTs though- there's a real risk of seriously messing up the picture and worse still getting a hefty shock.

Morse

Hi Morse,

Thanks for the info, I am going to try a magnet trick that I was told about but if that doesn't do anything then I will take it into the shop and see what they would charge to fix it up.

Tmod

Are you sure there isn't a setting for it in the menu? Most modern CRT monitors have that. If the setting has no effect there is a fault in the electronics.

He's talking about N/S error James, not E/W error. I've yet to see a consumer monitor with an adjustment for this, user or otherwise, though I haven't looked at very recent monitors. If they have such a setting now then it is good news and long overdue.

It is invariably caused by shoddy yoke/CRT mating or a duff yoke IME. Sometimes it's simple to fix, other times it's a non-starter.

Dave

That's more useful for corner convergence issues or small localised geometry issues. You might improve matters with a few magnets, but lifting the yoke should be tried first IMO as it's often the main cause of the problem and is very easily corrected without extensive fiddling with magnets, which is a bit of a black art.

Dave

Thanks Dave,

I am guessing that I have to cut loose the yoke from the adhesive that is connecting it to the foam pads. Then lift it and glue it back in place.

Is that correct?

I tried attaching magnets at differnet positions but it didn't give the results I was looking for.

I am attaching a link to the image of the yoke.

Tmod

That's usually the case, yes. Sony tend to use soft silicone adhesive rather than rigid epoxy so you might as a preliminary test be able to grasp the widest part of the yoke (taking precautions against shock hazards) and lift it slightly and observe the bottom of the picture for any improvement. If there's a noticeable improvement then you can remove the adhesive and reseat the yoke, using the existing wedges to hold the yoke in its new position. Once everything is spot on, then you can use silicone to fix the yoke, but IME it's not usually necessary as long as the wedges are tight.

A word of warning- if you need to undo the yoke clamp screw for any reason, do not overtighten it or the CRT neck will collapse with possibly dangerous consequences to you. Tighten it gently and only enough to stop the yoke moving under light force.

Once you've removed the silicone you'll find there's quite a range of movement at the wide part of the yoke, and you'll also find that sliding the yoke back slightly along the neck of the CRT will allow more movement, though it's best not to do this. If you absolutely must slide the yoke back slightly to allow for extra up/down movement, take extreme care that no shadows or convergence issues are created in the corners of the picture.

Once you have improved the bowing, you may find the convergence needs tweaking. The magnets may be of some help here.

Morse