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[NO LONGER FOR SALE] : 20" CRT Tube - working but perished convergence rings


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  • [QLD] - [NO LONGER FOR SALE] : 20" CRT Tube - working but perished convergence rings

    Central Brisbane area.

    This is such a bitter pill to swallow after such a high yesterday getting it in and working but it's my fault and will cost me. It's only money after all I guess.

    Just one day after installing a CRT in my cabinet (with as new Chinese chassis - literally looks like never been used before out of a box) I have a picture tube with convergence issues and perished (literally crumbling) convergence rings. The tube when I picked it up has amazing image quality/brightness but being an idiot I decided I could adjust the red/blue convergence rings and make it perfect. The ring tabs you use to adjust literally snapped off immediately upon movement.

    So anyway, the tube is working but now with a bigger convergence issue (this image is from when it was minor - the blue is now much worse offset). I can't even attempt to adjust it (yes I'm an idiot)
    CRT_Tube.JPG Picture.jpg
    Issues3.jpg IMG_6168.JPG

    The earth wire connector also has been broken at some point (got it like this) but still make the secure connection to neck board.
    Issues2.jpg Samsung.JPG

    Is it worth anything to anyone who can fix it? I don't think I can move forward with another CRT, my confidence in them is shot completely now unless I can get back on the horse with another tube before I sell the chassis and transformer. I literally spent $400 getting it all the parts together (Tube, Chassis, Transformer)and I'm about to give it away for next to nothing a day later.

    I'd really like to recoup 'something' for it. I also bought a brand new not used (that I can tell) degaussing wand.

    MAKE ANY OFFER for any of it you think you would like, you'll be surprised at what I'll take just to recoup something.
    Last edited by gsuttor; 24 February 2021, 09:29 AM.

  • #2
    Hey mate, just so you know for the future, that image displayed in your photo is totally fine for an arcade monitor.

    It's close to impossible to get a perfect image on an arcade monitor, especially when using a donor tube and wei-ya chassis. While that image was not amazing, it is well within acceptable ranges for arcade tubes. I can guarantee you that the monitors you played on when you were a kid were usually worse. Australia got a bum deal with arcade monitors, as most of what we got was Kortek, which were pure shit. Go to Japan and see the best Nanaos in action and they ran rings around the B-grade shit we got here.

    When I first got into arcades and CRTs, I spent months trying to tweak my monitors perfectly before I realised that it was kind of pointless. Every tube I have, and I mean every one, even the best Mitsubishi paired with the best Nanao chassis has red/blue convergence issues in the corners. Some of them are minor, some more noticeable, but all there.


    • #3
      Very true!

      - All CRTs were manufactured in the Northern Hemisphere and optimised to negate the effects of the Earths magnetic field, as it is there.

      In the Southern Hemisphere the Earths magnetic field is aligned differently (I think the vertical component is reversed, if I remember the theory correctly) and when the tubes arrived here they were all wrong.

      Readjusting the purity and static convergence (centre of screen) does help but the dynamic convergence (corners) is built into the design of the guns in the neck of a Precision Inline CRT and can't be changed.

      The compromise is to adjust the convergence for the best overall match, maybe a bit one way in the centre, the other way in the corners. Even the broadcast grade CRTs were never perfect.

      We do forget how crap the old TVs were compared to our HD LCDs, but that's a good enough reason to keep a few of the old ones running, for me anyway. Regards, John
      more from John's Retro Workshop -


      • #4
        i wouldn't be selling just a matter of finding another set of convergence rings which shouldn't be too difficult..


        • #5
          I'm burnt guys, and a complete idiot for thinking I could tweak a simple ring to make things perfect. The offer stands for anyone who is in Brisbane and would like a cheap tube +chassis +transformer set. It would cost me another couple of hundred in labour by a guy in Brisbane who can replace the rings but nope... the LCD + converter, as far from perfection it was, worked.
          I'm honestly completely deflated about the whole experience.

          Is $100 too much for the 'as new' Chinese chassis + transformer and munted CRT convergence? Make me an offer.

          I'm clueless at this stuff, a real freaking idiot noob out of his depth.


          • #6
            Clueless? absolutely not. Rygar World Champion, pretty impressive imo, whichever display you prefer to use is fine. All the best, regards, John
            more from John's Retro Workshop -


            • #7
              Hit up zanderzone and see if he can help you out with a good 20 inch tube and chassis. He probably has the largest monitor stash in Brisbane and is a stand-up bloke.

              Don't give up on the crt. If you want to see how good rygar can look and play on a nice CRT, I am happy to show you on one of my GroovyMAME cabs. Maybe you will play it on CRT and you will end up being perfectly happy with your LCD.


              • #8
                Originally posted by namastepat View Post
                Don't give up on the crt. If you want to see how good rygar can look and play on a nice CRT, I am happy to show you on one of my GroovyMAME cabs. Maybe you will play it on CRT and you will end up being perfectly happy with your LCD.
                I was playing on the CRT and loved it, there is something in the way the CRT converts the low res graphics that somehow make it look hires and much cleaner than the pixel-y LCD, when in alignment and focus. Stupidly I thought I could maybe get the top and bottom in alignment and as crisp, it's not until everything went wrong with the crumbling rings that I read up on it, and that only the central area of the tube is usually aligned/focused perfectly and the out edges can be slightly off.


                • #9
                  im selling this. $160 to you


                  • #10
                    Mate, grab the convergence/purity rings off another similar tube and use them on your CRT! You don't have to replace the whole yoke, leave that alone, just change the rings. Use some WD40 to loosen them up, and take a bit more care when adjusting next time.

                    I keep a couple of sets of old rings somewhere just in case.


                    • #11
                      Originally posted by sparkaruss View Post
                      Thanks for the offer but I won't be spending more money on CRT's. At this point I'm going to hold onto it and try to find the replacement convergence rings.

                      Barring that happening within the next few months I'll probably put it up again for sale without all the story and fanfare I've created here (sorry about that).
                      Just a plain super-cheap sale or giveaway if it comes to that. I'd love to see it working well and someone getting use out of it.


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