I'm new to all this. CRT warping/geometry issues: see photos. Easy fix?

[telecommand]

My House of the Dead III cabinet is almost perfect, except the monitor has these warping/geometry issues. Top-right and bottom-left appear to be "squished":

Can this be fixed easily? I live in Auckland NZ and don't have access to anyone who can repair CRTs (that I know of)... I'm willing to repair it myself if it's straightforward.

The game wasn't booting when I bought it, which I've since fixed. But because of that I'm unsure if the monitor was like this with the previous owner or if I bumped something while transporting it home...

Any help would be greatly appreciated!

 

[kikaso]

This is a convergence issue which can be adjusted with convergence strips. More information in this video.

Here’s a post by @GeeDee on how you can make your own convergence strips.

 

[stj]

or adjust the rings on the neck.

 

[kikaso]

or adjust the rings on the neck.

That too! Here’s another video, (I am a visual learner).

 

[telecommand]

Thanks for the links and tips! Just need to drive up the courage to give it a go. Also find a way to see the monitor while adjusting (a series of mirrors I guess!)

What parts are safe to touch? I'm terrified of shocking myself...

 

[nem]

Maybe it's the pic, but looks like it's slightly rotated too. Turn the deflection yoke to fix that.

Static convergence doesn't look too bad, so then it's just a case of sliding convergence strips under the yoke.

 

[kikaso]

Thanks for the links and tips! Just need to drive up the courage to give it a go. Also find a way to see the monitor while adjusting (a series of mirrors I guess!)

What parts are safe to touch? I'm terrified of shocking myself...

A mirror is the way to go.

You should stay away from the anode cap (attached photo) and always make sure you’re not grounding yourself while working on a live chassis and monitor. Keep one hand in your pocket and refrain from touching the deflection board and you should be fine.

 

[hatmoose]

hello fellow kiwi! I’m also based in AKL, sweet machine you have there!

Looks like some Geometry and some corner convergence.

The CRTs in some of those dedicated cabs are enormous (29 inches or larger) and the bigger the tube the more funky the geometry and corner convergence become. So this is a really common thing.

For a big tube your picture is not “Bad” - In fact it’s pretty good. I would strongly consider leaving it alone. But If you are determined to work on it I would address the issues seperately.

For the geometry you will need to attach magnets to the back of the tube to straighten out the lines. For a big tube this is an enormously painstaking process. Check out the number of magnets required to get good geometry on this massive 40” sony at 3:55

Once you’ve got the geometry good you can start on the corner convergence (also called dynamic convergence). For that we poke little strips of cardboard with tiny weak magnets under the yolk. Those convergence strips very slightly adjust the beam landing in the corners so they all hit the same phosphor at the same time.

So yeah,
Geometry with magnets on tube
Corner (dynamic) convergence with convergence strips

You might also want to take a look at the yolk alignment too, the picture looks slightly twisted clockwise to me, once you start messing with the yolk be prepared for a LONG process to retune geometry and convergence :-/

 

[telecommand]

hello fellow kiwi! I’m also based in AKL, sweet machine you have there!

Looks like some Geometry and some corner convergence.

The CRTs in some of those dedicated cabs are enormous (29 inches or larger) and the bigger the tube the more funky the geometry and corner convergence become. So this is a really common thing.

For a big tube your picture is not “Bad” - In fact it’s pretty good. I would strongly consider leaving it alone. But If you are determined to work on it I would address the issues seperately.

For the geometry you will need to attach magnets to the back of the tube to straighten out the lines. For a big tube this is an enormously painstaking process. Check out the number of magnets required to get good geometry on this massive 40” sony at 3:55

Once you’ve got the geometry good you can start on the corner convergence (also called dynamic convergence). For that we poke little strips of cardboard with tiny weak magnets under the yolk. Those convergence strips very slightly adjust the beam landing in the corners so they all hit the same phosphor at the same time.

So yeah,
Geometry with magnets on tube
Corner (dynamic) convergence with convergence strips

You might also want to take a look at the yolk alignment too, the picture looks slightly twisted clockwise to me, once you start messing with the yolk be prepared for a LONG process to retune geometry and convergence :-/

Thanks fellow kiwi! I wish there was someone in AKL who could do this for me You are right in that it's not that bad in the grand scheme of things. It's just the only thing that I consider "wrong" with this cabinet now so feel like I should address it at some point. The good thing is you don't notice it too much while actually playing the game. I will attempt to fix at some point!

 

[hatmoose]

Thanks fellow kiwi! I wish there was someone in AKL who could do this for me

I did consider offering; then I realised that there is probably 6-8 hours work in the thing, and it would all need to be done on site, and it was 50/50 it I would improve the situation, or just make it worse.

There are a few kiwis lurking on the boards, as soon as this covid bulls*t is done I've been thinking about organising some kind of meetup/beers. That Save Ferris place on Symonds st would have been great, but sadly also closed now due to covid. But yeah - will see about organising something when it's possible

 

[telecommand]

I did consider offering; then I realised that there is probably 6-8 hours work in the thing, and it would all need to be done on site, and it was 50/50 it I would improve the situation, or just make it worse.

There are a few kiwis lurking on the boards, as soon as this covid bulls*t is done I've been thinking about organising some kind of meetup/beers. That Save Ferris place on Symonds st would have been great, but sadly also closed now due to covid. But yeah - will see about organising something when it's possible

I would of course compensate you for your time if you end up considering again

Count me in for a meet up if it ever eventuates! COVID has wrecked any chance nowadays.

 

[stj]

"covid" didnt do anything - politicians did.
just saying.

 

[hatmoose]

"covid" didnt do anything - politicians did.
just saying.

100% with you on that - I dont want to get all political in this group - but this whole covid thing has really shown the limits of our system of government. Humans are social animals, but in very large numbers humans are... awful

 

[stj]

benime dislikes facts.

 

[Mukuro_W]

I hope you have already fixed your crt but it is clearly the yoke which is not well centered in place , you have to slightly rotate the yoke without touch the rings. To do this you have to loosen the retainer clip for first then move the yoke, the most important, you need a mirror in front of the rube and you will finish in a few seconds.