Sony KV32S42 with spot in upper left corner

[pac.attack76]

Sony KV32S42 has a 1 to 2 inch spot in the upper left corner that is discolored. Automatic degausser doesn't remove it and when moving the tv to other areas of the room, it slightly moves. Is there a way to correct this?

[old_tv_nut]

I don't know for sure, but some large color CRTs used purity trimming magnets glued to the back of the tube. If that's the case here, one may have fallen off.

Anyone here with more direct familiarity with this set?

[zeno]

Originally Posted by old_tv_nut

I don't know for sure, but some large color CRTs used purity trimming magnets glued to the back of the tube. If that's the case here, one may have fallen off.

Anyone here with more direct familiarity with this set?

Ditto
Sonys usually have little discs or discs glued to plastic sticks then
taped to the bell. They do fall off. You should have a pure blank
raster & a R, G or B color only. Put them in place & move around to
find the sweet spot.
If it comes back or cant be cured its usually the shadow mask broke
loose. Very common when the set gets dropped.
BTW when you junk a set save a few magnets.

73 Zeno

[pac.attack76]

I do have a few I saved. Ill pull the back today and check. I remember having a dead Sony wega some years back I revived with a couple ic replacements only to find it severely discolored from someone dropping it. The cabinet was cracked as well. Mask had shifted. At least this one doesn't have any cosmetic damage.

[pac.attack76]

Did they ever put any magnets behind the shield? This thing has a huge steel shield cover on the back. Or were they usually just around the yoke area? I do see 3.

[JohnCT]

Yes, there can be magnets behind the shield for trimming. The magnets have a larger effect closer to the yoke, but sometimes adding them closer to the mounting ears can improve the purity.

If the shadow mask is warped or broken free as Zeno points out, you can usually *fudge* this, but you will have to do this while the TV is pointing in the same compass direction as where it will be used. If you ever relocate the TV to a different wall, you will have to remove your magnets and reconfigure for the new direction.

Be aware that the trim magnets will also affect the geometry and edge convergence to some degree, so it always comes down to "robbing Peter to pay Paul".

John

[pac.attack76]

Can the mask be damaged without any damage to the case. I can't find any cracks or marks indicating an impact. I also couldn't find any lose magnets inside. Ill keep trying. Its real small, in the corner.

[zeno]

Usialy if you bang on the set you will see it. As a rule its very messed up.

[JohnCT]

Originally Posted by pac.attack76

Can the mask be damaged without any damage to the case. I can't find any cracks or marks indicating an impact. I also couldn't find any lose magnets inside. Ill keep trying. Its real small, in the corner.

Certainly. The Trinitron was by far the most susceptible to warped/dislodged shadow masks and it didn't take a lot. Just falling on its face would be enough, something that was common because CRT TVs are so damned front heavy.

I've also seen a Sony mask damaged by a manual degaussing coil.

But as premium a product as Sony was, we got by far the most complaints about geometric distortion or convergence errors from Sony. Even the low end RCAs had the pre-yammed yokes (zero adjustments available) and those things were all virtually perfect, every freaking one. In other words, yours might have fallen in the realm of "normal" back then.

Can you post a pic of it?

John

[JohnCT]

Originally Posted by zeno

Usialy if you bang on the set you will see it. As a rule its very messed up.

Yes! If the shadow mask has broken loose, tapping on the TV will show a fluttering in the area of concern for a few seconds. I forgot about that.

John

[pac.attack76]

Yes, ill get a pic in a few. I've never had a Sony with good geometry. Any other set was always perfect to me. I got it to look a little better. Moving it to a different position in the room caused a little spot in the bottom left corner as well.

[pac.attack76]

Pics as it is now.

[old_tv_nut]

I would try a manual degauss first, and then if that doesn't help, a magnet.

[JohnCT]

Originally Posted by old_tv_nut

I would try a manual degauss first, and then if that doesn't help, a magnet.

I seem to recall a bulletin from Sony not to manually degauss certain models. I don't think it would do any harm with most degaussers but somewhere I have one that has a powdered iron core (damned thing weighs like 5lbs). That thing could slow traffic...

John

[pac.attack76]

Originally Posted by JohnCT

I seem to recall a bulletin from Sony not to manually degauss certain models. I don't think it would do any harm with most degaussers but somewhere I have one that has a powdered iron core (damned thing weighs like 5lbs). That thing could slow traffic...

John