Fix rotation on CRTs?

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eliteshmupper
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Fix rotation on CRTs?

Post by eliteshmupper »

Hi, I have a few CRTs with this issue, presumably due to shipping. I'm not entirely sure if the whole tube is slightly out of whack or if it's something with the yoke, but the symptom is always the same, the image appears to be rotated to some degree, sometimes clockwise, sometimes counterclockwise. No way to do anything about it in the service menu. Is there any good guide for fixing this problem?
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BazookaBen
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Re: Fix rotation on CRTs?

Post by BazookaBen »

A picture would help
accaris
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Re: Fix rotation on CRTs?

Post by accaris »

Some late-model Trinitrons have a rotation option in the service menu called TROT.

Most of the time, the only fix is to open the back, slightly loosen the screw holding the yoke to the tube neck, and manually rotate the yoke yourself.
Exidna
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Re: Fix rotation on CRTs?

Post by Exidna »

If you're seeing the same thing on multiple CRTs, it's probably due to earth's magnetic field than shipping damage.
A number of late-model CRTs - not just trinitrons - had options to correct for this.
gray117
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Re: Fix rotation on CRTs?

Post by gray117 »

+ just to check - you're definitely talking about (the typically hidden on consumer sets) service menu and not the regular adjustment menu?

Specific crt models in question? (perhaps someone has some specific advice/experience).

Large metal girders/construction elements can also distort magnetic fields in a similar manner (though tend to be a wavey effect in relation to a bar length) - though as others noted rotation likely to be due to location/earths magnetic field. Most screens should have corrections for this very reason (manufacture in one place, ship to all over the world).
eliteshmupper
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Re: Fix rotation on CRTs?

Post by eliteshmupper »

As far as examples go, here is a light case of it on a Sony KV-14LT1E. http://i.imgur.com/JE9tK37.jpg Sorry in advance to everyone who has the same issue on their CRT and was oblivious to it until now :) This is a 2000 model and there is no option for rotation in the service menu, but I have also seen worse cases on PVMs and early 90s Trinitrons without service menu. I don't care about the other geometry imperfections with CRTs, but this one really sticks out to me.
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BazookaBen
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Re: Fix rotation on CRTs?

Post by BazookaBen »

eliteshmupper wrote:As far as examples go, here is a light case of it on a Sony KV-14LT1E. http://i.imgur.com/JE9tK37.jpg Sorry in advance to everyone who has the same issue on their CRT and was oblivious to it until now :) This is a 2000 model and there is no option for rotation in the service menu, but I have also seen worse cases on PVMs and early 90s Trinitrons without service menu. I don't care about the other geometry imperfections with CRTs, but this one really sticks out to me.
My Hi-scan trinitron actually had a rotation option in the user menu, not service menu.
gray117
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Re: Fix rotation on CRTs?

Post by gray117 »

It may require a different button combinations, but I don't think I've seen a 90s trinitron without a service menu. Some early ones I think can be accessed by both holding both volume buttons (on the set not on the remote ... or was that both program buttons ... one of the two :)

Service manual annoyingly enough suggests the 21 inch could adjust rotation from regular menu... there's some other references to rotations but not sure if it's what we're after. You might be out of luck with rotations on the 14" model unless you manually adjust.

http://j.mdownload1.free.fr/Schemas/Son ... 14LT1x.pdf
accaris
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Re: Fix rotation on CRTs?

Post by accaris »

BazookaBen wrote:
eliteshmupper wrote:As far as examples go, here is a light case of it on a Sony KV-14LT1E. http://i.imgur.com/JE9tK37.jpg Sorry in advance to everyone who has the same issue on their CRT and was oblivious to it until now :) This is a 2000 model and there is no option for rotation in the service menu, but I have also seen worse cases on PVMs and early 90s Trinitrons without service menu. I don't care about the other geometry imperfections with CRTs, but this one really sticks out to me.
My Hi-scan trinitron actually had a rotation option in the user menu, not service menu.
A lot of late model Trinitrons have this, but it rotates in big chunks... for very fine rotation, the service menu setting called "TROT" can let you rotate at fractions of degrees.
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Restart_Point
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Re: Fix rotation on CRTs?

Post by Restart_Point »

On a tangent, my Trinitron's image rotates slightly when I put it in the desired position in my room. It's ridiculous and annoying but true. Don't think it's because of any metal furniture or other devices, can only guess it's metal or power cabling in the walls or something. When I plug it in a different room in the house it goes straight again. I'm just thankful I worked this out before i tried messing with the deflection yoke, which I was considering.
Dochartaigh
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Re: Fix rotation on CRTs?

Post by Dochartaigh »

On PVM's, unless you have a higher end model like a 20L5, 20M4, etc. you'll have to manually rotate the yoke. Even their 14" variants of those higher-end models don't have this in the service menu if my memory serves. REALLY annoying when a $400 MSRP Consumer TV has the option to rotate in a menu but the $1,800+ PVM doesn't...

And this is the single most common tweak I have to do to PVM's when they come in - like a good 60% of them need it done.
jd213
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Re: Fix rotation on CRTs?

Post by jd213 »

Dochartaigh wrote:On PVM's, unless you have a higher end model like a 20L5
My 20L5 has a slight rotation problem, but I was never able to find a menu setting that rotated the picture, even in the service menu.
Namingway_PL
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Re: Fix rotation on CRTs?

Post by Namingway_PL »

I had this issue in one of my PVM's due to shipping . PVM monitors don't have the rotation setting, I fixed it by slightly rotatating the yoke.
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LEGENOARYNINLIA
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Re: Fix rotation on CRTs?

Post by LEGENOARYNINLIA »

gray117 wrote: Large metal girders/construction elements can also distort magnetic fields in a similar manner (though tend to be a wavey effect in relation to a bar length) - though as others noted rotation likely to be due to location/earths magnetic field. Most screens should have corrections for this very reason (manufacture in one place, ship to all over the world).
I had this problem because of a small Ikea table lamp once.
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ChuChu Flamingo
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Re: Fix rotation on CRTs?

Post by ChuChu Flamingo »

I assume you do this while the crt is powered on when adjusting yoke.
Dochartaigh
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Re: Fix rotation on CRTs?

Post by Dochartaigh »

jd213 wrote: My 20L5 has a slight rotation problem, but I was never able to find a menu setting that rotated the picture, even in the service menu.
I tried to find my notes for this (and failed), but I believe it's called landing (only have my 14L5 out now otherwise I would double-check). It only rotates it a little bit, FYI.


ChuChu Flamingo wrote:I assume you do this while the crt is powered on when adjusting yoke.
Yes. In a nutshell, loosen the clamp screw near the guns (some models have two), and I always wear rubber gloves just in case, and GENTLY muscle it (rotate) to one side. Some funny sounds can occur as the epoxy or whatever they use breaks loose, and you can loose a rubber shim if it's ancient and the glue it totally gone, but that's about it. Tighten the screw back and it should be good (just got done doing this to like 6x PVM's last week).
thebigcheese
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Re: Fix rotation on CRTs?

Post by thebigcheese »

Does anyone happen to have pictures of the process? I would like to rotate the yoke on my PVM to fix the rotation and it seems pretty simple, but I just don't want to mess it up and I've not had much luck finding exactly what to look for.

Edit: j/k, this video explains it all and it looks super, super easy: https://www.youtube.com/watch?time_cont ... zdZZbI1BzU.
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mikejmoffitt
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Re: Fix rotation on CRTs?

Post by mikejmoffitt »

Landing affects purity.
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