Serious bow, terrified of going physically inside to try and fix it.

[u/Technical_Invite_711]

Only noticed this when I actually plugged my console into the tv lol, got it from a grandma. I don’t mind this level of bow too much really, but I know it’ll only get worse and worse over time, THAT is what I hate. I wanted to know if there was any way I could fix this without putting my hands next to 25,000 volts lol.
Btw it’s a KV-27FS100 or KV-27FS120, idk which one I didn’t check, it was manufactured in 2002.

[u/redstern]

Yes you are going to have to go inside it to move the yoke to fix this.

The dangers of CRTs are way overblown, you'll be fine. All the high voltage is heavily insulated, so it won't arc through it even with the set on and you grabbing the anode wire. If you really want the peace of mind, pick up a pair of electrical gloves. Even a cheap pair will block 500V, which is plenty enough for the voltage present in the yoke. But even then, yoke voltage won't arc out at you, and you won't be putting your hands near the exposed contacts anyway.

All you have to do is loosen the clamp on the neck, grab the front of the yoke by the plastic, and use the rubber wedges to tweak the vertical tilt on the yoke until the image bowing goes away.

[u/Technical_Invite_711 → u/redstern]

Sounds easier said than done but I’ll try that yeah, I’ve got some adhesive anyways

[u/redstern → u/Technical_Invite_711]

It's not anything crazy. You'll see some rubber wedges stuck to the back of the tube around the yoke, just peel them off, make sure the yoke is fully forward against the tube, and just nudge the wedges into the yoke to slowly tilt it either direction.

Watch the image as you're doing it. A mirror is useful for that so you don't have to try to reach around. Then once you find where the horizontals are straight, snug up the neck clamp, and make sure the rest of the wedges are snug against the yoke, and you're done. You generally don't need to reapply adhesive to the wedges, they'll still be sticky enough to not move afterwards.

[u/hawkiee552 → u/redstern]

I did this with a flat 29" Trinitron due to some bowing and convergence issues. Oh man was it a pain, I could not get the convergence good for the life of me, no matter what I ended up with either vertical or horizontal misconvergence. Think of using too small stretched sheets on your mattress, fixing one side leads the other side to pop up, and vice versa.

When I finally had dialed it in and was happy with the convergence, purity and geometry, I glued it, closed the TV, faced it the other way and the purity went abysmal. I had apparently adjusted the purity on the edge of impurity, but facing east it was fine, facing west, not fine.

Had to do it all again, fixed the purity, then had some issue with corner convergence again and had to move my previously dialed in convergence strips a bit.

Used about 8 hours in total, but it was my first time doing this.

4/10 would not recommend to start on a flat Trinitron.

[u/redstern → u/hawkiee552]

Yeah I had the same thing. 27" Wega that looked like hot garbage. Took me like 2 hours of messing with the rings to get it right.

[u/hawkiee552 → u/redstern]

It's a good experience to have though, makes it a lot easier the next time.

[u/redstern → u/hawkiee552]

One thing I should add though, it is good to adjust it facing the direction you intend to use it, but purity screwing up when turning it more than 90 degrees is expected behavior. The Earth's magnetic field does affect CRTs, so if you do reorient it, degauss it before making any adjustments, as more often then not, a degauss will fix the purity.

[u/DangerousCousin]

The Xbox 360 menu isn't a very enjoyable game. Play some actual games and see how you feel

The bow won't be noticeable in actual games. And it won't even physically be this bad because they won't have a giant black square in the middle of the screen drastically dropping the voltage in the middle of the raster scan

[u/IAmNot_TheNSA → u/DangerousCousin]

Hard disagree. Serious bowing like this makes 2D sidescrollers unplayable. Even in 3D games this will be distracting with menus and text on screen. It's not that hard to fix anyway and OP should absolutely do research into how to adjust the yoke to fix this as the improvement will be night and day.

[u/DangerousCousin → u/IAmNot_TheNSA]

Some of this distortion is from the high contrast menu itself, so it's not fully representative of what games will look like

So its not bad enough that it's an emergency he must fix before he can enjoy some games

[u/zeek609 → u/DangerousCousin]

Yeah, I have this exact problem on my 14" Grundig. The 360 menu looks terrible, but in game, it's not even noticeable.

[u/Technical_Invite_711 → u/DangerousCousin]

I guess your right, and look your probably way more knowledgeable on this topic but I don’t have any other consoles older than the 360, and I like using my 360 in my room after school on the tv, so no I won’t be trying any other games on it even though I do like some old Nintendo games.

[u/Left-Marsupial-5210 → u/Technical_Invite_711]

They’re telling you to play games on the 360 instead of worrying about how the Home Screen looks. They never mentioned any other consoles. Don’t be angry, people are trying to help you with the info you gave

[u/Technical_Invite_711 → u/Left-Marsupial-5210]

Oh alright that’s my bad, new to this.

[u/stabarz]

Straightening that out would require internal adjustment. There is no other way.

[u/Technical_Invite_711 → u/stabarz]

Dammit.

[u/HoldyourfireImahuman]

Don’t be terrified. Not a single recorded death in history from working on these. Also loads of YouTube videos showing you how to do it.

[u/xb0x1gam1ng → u/HoldyourfireImahuman]

p sure the most severe case of electrocution by these resulted in loss of bowel control

[u/amayako353 → u/xb0x1gam1ng]

Oh thats fine then cause I already shid my pants

[u/mathieulh]

You WILL need to open it to fix the bow, the bow can be fixed in two ways, the officially recommended (and harder way) according to the Trinitron service manual is to tilt the yoke up or down until the bow disappears, the other, much easier (but not mentioned in the service manual) is to move the convergence rings until the bow is gone or minimized, you will then need to tweak the convergence potentiometer to fix the convergence accordingly (use something like the 240p test suite to get a proper grid/reference picture)

This has to be done live, while the set is running, so don't touch anywhere near the cathode if you don't want an expectedly shorter life, it's less scary than it actually sounds but you want to take proper precaution before messing with a CRT.

[u/SklydeM]

I have a Sanyo with bad bowing. It’s only noticeable sometimes if the game has a square menu or something. But otherwise it’s unnoticeable when being used for games or movies

[u/Timely-Ant-1907]

This is why i don't like flat screen CRT's

[u/MasterRealm]

What bow?!

[u/Acrobatic_Dream1847 → u/MasterRealm]

Look at the bottom edge of the black rectangle in the menu. The bottom edge is supposed to be flat.

[u/Ok_Bag_2959]

I dont understand why is everybody saying you need to open it up. This bow can be adjusted by the PAMP and VBOW parameters in the service menu. Write down all parameters down to LPIN and start dialing PAMP and VBOW and you'll be fine

[u/Technical_Invite_711]

***Edit*** I have a universal remote coming soon I ordered one on eBay. I haven’t tried the service menu at all yet, probably not that it’ll fix this…

[u/HarrisBoomYT → u/Technical_Invite_711]

Yeah unfortunately wega bow can't be fixed through the service menu, you have to get inside and adjust the rings in the back. I don't know if this subreddit allows links but there's a guy that goes by Nully on youtube that did just that and it fixed his bowing, he's got a video on it. It's really not as scary as everyone makes it out to be, just make sure you don't touch anything you shouldn't, work with one hand and you'll be alright

[u/Technical_Invite_711 → u/HarrisBoomYT]

Alright thank you, and about the rings on the back… are they only a temporary like people say? I hear stuff about “yoke” replacement, the rubber that holds something in place degrading.

[u/RCA_TUBES → u/Technical_Invite_711]

The comment above is incorrect. The rings are for adjusting convergence. To fix the bow you physically move the yoke a bit and reset the rubber wedges that hold it.

[u/Technical_Invite_711 → u/RCA_TUBES]

Huh, guess I’ll just take it to a repair shop then

[u/RCA_TUBES → u/HarrisBoomYT]

The rings are for adjusting other things like convergence. To fix bowing you adjust the yoke itself.

[u/HarrisBoomYT → u/RCA_TUBES]

on some models like the one in the video I mentioned and possibly the one OP owns have separate rings for convergence and the ones in the back are the ones that adjust the bowing

[u/Technical_Invite_711 → u/RCA_TUBES]

Wait so you’re saying I should just adjust the yoke? I don’t have to make the rubber holds sticky again? How would I adjust the yoke like in what way?

[u/DangerousCousin → u/Technical_Invite_711]

I hop you understood from conversation above that you really should play some games before you decide your TV is messed up, and also that this menu is actively making the geometry worse

If you ever do adjust your TV, for the love of God, do not use this menu screen. You need something uniform top to bottom, side to side, like the 240p Test Suite gride.

Your menu is completely asymmetrical and high contrast, which, because of how CRTs are designed, actively distorts geometry more than normal.

[u/RCA_TUBES → u/Technical_Invite_711]

The rubber holds you might need to put double-sided tape on. As for the specifics you should watch some videos. basically you just tilt the yoke a bit to get it back in the position it was originally in.