In this thread we tube and yoke swap monitors

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    • In this thread we tube and yoke swap monitors

      A general thread for uncommon monitors. Common monitors should probably get their own threads, like this

      Alright School Me Please - Nanao MS2930/31/33 Tube Swap

      Anyway, we're heading into the twilight years of finding CRT tubes out in the wild. I've been monitoring the local craigslist for CRT TVs for years, and pickings have gone slimmer every year. Now's the time to act if you still want a burn free tube for your arcade cab.

      Today's project is a Hantarex Polo 25" (59cm) 25kHz monitor out of a Sega Rally upright. Here it is:



      Sega Rally has a pretty terrible attract screen for burn in. They really didn't think that one through. You have a credit text and counter, the manufacturer and date, and a high score board that's like 50% of the time visible on the screen. A linked cab will mix it up with a '2 Player Racing' text. Inevitably after years of operation the tube will look like this:



      Yikes.

      The original Hantarex tube is a Philips A59EAK552X44. From what I've understood Philips tubes are paired with their yokes. You can't put a Philips yoke on another brand of tube and you can't put another brand of yoke on a Philips tube. So I need a Philips tube. Measuring the original yoke with the BSIDE ESR02 Pro I get 0.37mH for the horizontal and 6.06mH for the vertical. Cross referencing that with the deflection yoke data on consumer TV's found here I can see there's a TV set (A59ESF002X42) that could work (although the horizontal is 15% off), but I bet the chance of finding one will be slim to none. So instead I'm going to look for a compatible tube and swap the yoke. Notice how there is no yoke ring set on these. I think there's a single ring on these that has been permanently magnetized with all the necessary corrections. That means if purity and and static convergence are off with the donor tube, there's no way to fix it.

      Here are our candidates for the tube swap:




      Philips TVs will (always?) have a Philips tube inside of them, but the Samsung was a lucky discovery. Samsung also make their own tubes, but inside this Samsung CX-5937AN was a Philips A59EAK71X01 tube. I will henceforth refer to these tubes as Samsung (left) and Philips (right).

      Eyeballing the Samsung tube it was a perfect match. Exact same size and curvature, and the yoke looked exactly the same (only looked, the horizontal inductance was way off). The model numbers are different, but I'm going to put that down to manufacturing date, the factory it was built in and the different yoke. This bodes well. Here are the two tubes stripped:



      I plunked the original yoke from the Hantarex on the 'Samsung' tube. Original dag wire and degauss coil were also swapped. It's just way easier than putting new connectors on the 'Samsung' ones. Connected the tube to the chassis and the whole shebang to the cab. Turned on the cab and



      it looks great! I didn't even need to mess with the picture controls at all! I was expecting the geometry to be off, but it's absolutely fine. I had my doubts, but it's a complete success.
    • Inspired by this, surely the other tube could work as well? The Philips TV (25PT5321) has a slightly newer tube (A59ESF002X11). The size and curvature are again exactly the same. The dog ears are at the correct depth. However, it is slightly different looking (notice the wider metal band) and the yoke is different. Similar, but different. Both tubes stripped with their yokes:



      Original Hantarex yoke was dropped on the Philips tube. Again, I wanted to keep the original dag wire and degauss coil. This created a problem because the Philips tube is missing the horizontal slits on the metal band for mounting these. I reused the plastic hooks found inside the TV for the degauss coil. They go over the dog ears and hold the coil in place. As for the dag wire, I drilled a small hole in the metal band for the spring:



      Probably not what they teach you to do in TV repair school. Anyway, that's those sorted. Now for testing! Connected everything up and turned it on. Fingers crossed and



      uh oh. Huge purity issues. No amount of degaussing will make these go away.

      Oh well, at least one success story out of these two. So for Philips yokes that have a single yoke ring, if you have an exact tube match the likelyhood of success is good. If you don't, it probably won't work.
    • This one is for @nassekova. A Hantarex Polo 28" out of my Baldazzi Styl Art Capcom Q Sound cabinet ("Euro Big Blue").

      Here it is:



      Tube is a Videocolor A66ECY13X01. The tube isn't actually all that bad. Good colors, good focus, just some minor burn in. I'm going to keep this as a spare. Anyway, Videocolor tubes are super common in European 28" televisions, like this:



      A Finnish Nokia 7156 television, with a Videocolor A66EAS13X01 tube insde. The tube has a different curvature, but since the bezel in the Euro Big Blue only goes over the frame and not the glass, it doesn't matter. The Nokia is actually more curvy, which I'm a big fan of. Flat displays belong in LCDs!

      Here are the tubes side by side, Nokia on the left, Hantarex on the right:



      The BSIDE ESR20 tells me the yokes are an exact match for horizontal. It's just a case of swapping yoke leads. Original leads on the Hantarex on the left, then transplanted to the Nokia on the right:



      (If someone is copying this, I had both horizontal and vertical reversed. Correct order is orange, yellow, brown & red)

      I then put the original dag wire and degauss coil on the Nokia and the tube inside the frame. Connected the monitor to the cab and a after a slight fiddle with the adjustments on the remote I have this:



      :thumbsup:
    • hoagtech wrote:

      I was waiting for a thread like this

      This gives me faith to try a 25” JVC donor.
      Wish I could find any 25" sets around here.

      People don't know how to take a picture of the damn model sticker and so they just list things on CL and FB as 'TV' or something equally difficult to filter on.

      Thought I found one the other day--the person specifically said it was a 25" in the listing--went and picked it up and it was a 27".
    • It's funny how the situation is completely the opposite here versus you guys in the US. Here's what I have loads of (European / Japanese sizes)

      19" tubes (48cm) with a B10-277 neck
      25" tubes (59cm). I even have tubes that should be drop-in with compatible 0.300mH yokes for a MS8
      28" tubes (66cm)

      However, I can't for the life of me find

      19" tubes (48cm) with a 8-pin B8-294 neck for a K7000 (in four years I've found 1... out of a Bang & Olufsen)
      26" (63cm)
      29" (68cm) (again, in four years I've found 1)

      Guess what tubes I need way more of?
    • Finally managed to snag an A63 this weekend; no bonded yoke and has a set of purity/convergence rings, so we're off to a good start. Need to measure the yoke inductance still, though. Also, picked up 3 A68s over the last couple weeks but they're going back on FB marketplace--they all have bonded yokes and a preset convergence magnet.

      I've found tons of A68s here, but almost all of them have had bonded yokes and preset convergence magnets so they're not suitable for swaps.

      Also, not all Phillips TVs (in the States, anyway) have Phillips tubes. I've definitely picked up some A68s and an A59 that were Funai.