In this thread we tube and yoke swap monitors

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    • nassekova wrote:

      I think you said to swap that MTC9000 flyback with a HR702, why is that?

      HR7025

      Because the original flybacks are junk. I've had two explode like this:



      I just measured the TTD tube in my Turbo Outrun and I got 1.86mh for horizontal, and 29.2mH for vertical. So your horizontal is definitely different, but I'm not saying it won't work. I can check some other tubes that I have working tomorrow.
    • nem wrote:

      I forgot X/

      Checked two more

      Orion A48JRV70X12
      lh 1.66mH
      lv 30.7mH

      Samsung A48ECR31X59
      lh 1.91mH
      lv 29.1H

      So yeah, out of three tubes none have a horizontal inductance as low as yours. I have at least two more working tubes, but they're way, way back in my storage room.
      Well shit... :thumbdown:

      I guess I'll still try it with the MTC 9000 and if it does not work, the quest continues...
      Wanted: -

      My Instagram about retrogaming. Mostly Japanese imports. Some restoring, BEER and obscurities!
    • Is there some kind of centralized list of compatible tube / chassis combos that you guys work from when swapping out tubes? Or do you keep buying up old CRT TVs to test until you find one that works?

      I'm not great with working on CRTs. I can see that you're measuring the mh. Do you have some way of narrowing it down first before you buy new tubes? And, how do you measure what's needed for an old monitor if it's too broken to turn on?

      I'm looking to reuse a curved 29"/27" Samsung tube (A68QBT892X) from a Kortek KT-2938f. It makes disconcerting fire-cracker-like bangs when I turn it on but the tube seems intact. How would you guys go about finding a compatible replacement (CGA) chassis?
    • Zebra wrote:

      Or do you keep buying up old CRT TVs to test until you find one that works?

      Pretty much. Except I very rarely buy anything. Unless it's an uncommon size (like 29" / A68), I'm not paying a single cent for these. They're trash to people, they should be paying me.

      Tubular will tell what neck it has and what heater voltage it's using, but honestly, everything that I've found (in Europe) that hasn't been a Sony has had a B10-277 neck and a heater voltage of 6.3V. Which is great, because apart from your stupid Wells Gardners, that's the most common connector and voltage on arcade chassis too.


      Zebra wrote:

      And, how do you measure what's needed for an old monitor if it's too broken to turn on?

      Doesn't matter if the chassis is broken. As long as the tube and yoke are OK, you're good.
    • Ok, Finally got around to removing the back case to see what I've got inside the RCA 19" F19421 crt I picked up a few weekends ago.

      Hmm.. the internet identifies the A48LGS30X03 tube as a CR-31 8 pin with a H at 2.9 ohms and a V at 12.8 ohms.

      I don't see this tube number listed on noted incomplete inventory. Should I continue on with the search for a WG 19" K7000 compatible crt?
      Images
      • 20201111_131230_rotated_resized.jpg

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      I think I need to learn to solder.....

      The post was edited 1 time, last by MudGuts83: corrected neck info to CR-31 ().

    • It's time I explain my situation:

      I own a twin Time Crisis 2 with awful tubes (to the point fixing major problems between both chassi didn't improve the image). I have two Orion tubes that came from a later Toshiba made TV I intend on swapping but am a bit unsure if they would be compatible. The chassis used and specs of both factory and potential donor tubes as follows:

      Factory Chassis: Wells Gardner K7400 (WGM 2774) 27"

      Factory Tube: Zenith A68AHE00X, 110° (incorrectly predicted as 100°), rather curvy for a 27" for some reason

      Donor Tube: Orion A68QCU870X, 110°, (almost) flat

      The neck pinout on both tubes are the same. The measurements of the two yokes in resistance and inductance are yet to be determined. Both yokes are fortunately not bonded to their respective tubes. My prediction is that this may be a compatible swap but with (hopefully manageable) geometry issues.
      My projects: Motocross Go x2

      The post was edited 1 time, last by Hydreigon ().

    • nem wrote:

      Zebra wrote:

      And, how do you measure what's needed for an old monitor if it's too broken to turn on?
      Doesn't matter if the chassis is broken. As long as the tube and yoke are OK, you're good.

      Oh right, this was a pretty poor answer.

      Tubes can be visibly checked. More often than not if the tube is damaged it's broken at the neck. As for checking emissions or shorts, you could bring a CRT analyzer / rejuvenator with you. This said, very few TV sets are ever run into the ground like arcade monitors are.

      As for the yoke, you could check it with a BSIDE ESR20. You should be able to spot shorted windings with one.

      Anyway, 99% of the time the chassis is the one to go first. I never do any of the above. If the owner tells me the TV is broken, I ask if it's been dropped. If the answer is no, I'm like cool, I'll take it.
    • One thing I've run into with this blast city swap I'm doing is the tube itself.

      The numbers match up, the yoke and chassis line up great, all of that stuff is perfect.

      The tube out of the tv is either thicker, or the mounting holes are in a different placement. So you may have to rear mount or off set it a bit. I can get the Orion tube in there just fine, but the blast bezel wont fit at the bottom. Or maybe its in my head and the blast bezel just sucks.
    • I always test fit the bezel with the tube outside of the cab. That way you can see if the curvature matches. Then it's just a case of getting the mounting depth correct.

      All four dog ears are at the same depth on the tube, so there's no reason why it shouldn't fit at the bottom too. This said, I don't know what it is about Blast Cities, but I always have to press the bottom of the bezel damn hard to snap in place. Otherwise it pops out. This is with original tubes.
    • nem wrote:




      All four dog ears are at the same depth on the tube, so there's no reason why it shouldn't fit at the bottom too. This said, I don't know what it is about Blast Cities, but I always have to press the bottom of the bezel damn hard to snap in place. Otherwise it pops out. This is with original tubes.
      This is the exact problem I am having. So it's not the tube, its just a pain in the butt to get the bottom of the bezel to snap in place.
    • New

      nem wrote:

      I always test fit the bezel with the tube outside of the cab. That way you can see if the curvature matches. Then it's just a case of getting the mounting depth correct.

      All four dog ears are at the same depth on the tube, so there's no reason why it shouldn't fit at the bottom too. This said, I don't know what it is about Blast Cities, but I always have to press the bottom of the bezel damn hard to snap in place. Otherwise it pops out. This is with original tubes.
      I rear mounted this, and the bezel pops in like a charm. What's odd, even with the tube numbers line up, the Orion is a tad bit flatter.
    • New

      Some test results are in from various tube yokes.

      Orion A68QCU870X 27" flat tube
      LhLvRhRv
      1.2 mH18.2 mH1.8 ohm9.2 ohm



      ORION A68KTB180X 006 27" curved (Toei TC-L292)
      LhLvRhRv
      .88 mH18.9 mH1.8 ohm7.7 ohm



      Hitachi A68KRQ58X tube (Wells Gardner K7500 27")
      LhLvRhRv
      .36 mH14.2 mH0.8 ohm5.7 ohm



      Wells Gardner K7400 25" compatible yoke
      LhLvRhRv
      .9 mH17.9 mH1.3 ohm6.9 ohm



      Toshiba A68KJU96X (Nanao MS9)
      LhLvRhRv
      .29 mH14.2 mH1.5 ohm6.5 ohm



      The TC-L292 and K7400 are close with the TC-L292 having more vertical inductance and overall resistance. The K7500 and MS9 are extremely close to the point K7500 27" tubes may as well be used for any MS9 chassis without a yoke swap. I'm kind of surprised. It looks like I may have to change my plans for Time Crisis 2.
      My projects: Motocross Go x2

      The post was edited 1 time, last by Hydreigon ().

    • New

      So it turns out the factory tube in my Time Crisis 2 actually has a deflection angle of 110° as opposed to 100°. A tube swap for those Orion tubes may be possible. I have measured the yoke as well:

      Zenith A68AHE00X 27" tube (Wells Gardner K7400)
      LhLvRhRv
      .91 mH16.1 mH1.3 ohm8.3 ohm



      It seems the K7400 may have some vertical inductance tolerance.
      My projects: Motocross Go x2