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TV to arcade CRT?



So if anyone has been following my dilemma they will know I had a CRT for a day then like a muppet I wrecked the convergence rings by trying to slightly adjust them. They literally crumbled/snapped with the tiniest bit of adjustment using one finger, they were severely perished.

Perished_Rings.thumb.JPG.0eda5532ef55bcfc2e0aa3a3c84f1bf5.JPG Sans_Rings.thumb.JPG.2ec3fa343cf511f8d8102cb127e17f76.JPG Samsung_Model.thumb.JPG.8057b7117797c7c02cf9edeca81ec381.JPG


I learnt an expensive lesson to never mess with 30 year old tube convergence rings... bad me.. anyway. Let's move on form that.

So after a conversation with an AA member the option of using a doner TV tube with a JOMAC chassis was suggested. I picked up a 20" TV for $10 off Gumtree previously, this is literally throw away if I have to throw it away and find another. However, it was suggested that most tubes are pretty darn good and what really makes the difference is the chassis. Hope I got that right.

The neck/rings are smaller diameter but I;m not sure if the pins that attach to the neck board aren't the same size? Haven't attempted anything as I'm here writing this up for any advice.



Here is the tube/chassis etc. from the TV

IMG_6295.thumb.JPG.99e472ddca3aba38084c35468ece7c9c.JPG IMG_6298.thumb.JPG.d60ec2c002e9a7b95840211ee9d2726a.JPG


IMG_6296.thumb.JPG.aa4d790e0e3f3bdc3bba652d7d3caf62.JPG IMG_6299.thumb.JPG.552ca2ce001bda990a9b7e4421077dd7.JPG



So the chassis that was running the arcade CRT (for a day and seemed to be doing ok) was this Chinese one.

IMG_6307.thumb.JPG.95ffa30cb4743af3dc3c99a792cb7d54.JPG IMG_6306.thumb.JPG.2b268815665305f3323d99ffdd4fd010.JPG

IMG_6308.thumb.JPG.14642d0455556aca0331c8dead2eb2a6.JPG IMG_6310.thumb.JPG.10d6ef9cc498722f46bb4fd5456ed26e.JPG




So this chassis runs off 110V step down transformer. If the neck board fits, what else has to be done?

Do I need to send the chassis to JOMAC with yoke readings to get modified or do I need a diff chassis?



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The actual model number is listed as an example here below underlined


Chinese System

According to this system, the type number consists of three to four symbols.


Examples: 14SX5Y4, 37SX108Y22-DC02, 54SX503Y22, 73SX707Y22-DC26

  • The first symbol is a two-digit number designating the minimum diagonal in centimeters of the CRT face (e.g. 37 = 37cm).

  • The second symbol consists of the letters SX followed by one to three numbers designating a specific CRT family whose members have common optical, electrical and mechanical characteristics.

  • The third symbol consists of the letter Y followed by a number designating the phosphor type. For instance, Y22 designates a color picture tube phosphor and is the equivalent of P22 in the EIA system, B22 in the EIAJ system and X in the Pro Electron system. Y4 designates a monochrome tube phosphor and is the equivalent of P4 in the EIA system, B4 in the EIAJ system and W in the Pro Electron system.

  • The fourth symbol or suffix (e.g DC01, DC02, DC03, etc.), separated from the main type number by a hyphen, is only used for tubes having integral neck components (bonded yokes and adjustment rings).

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Hi, I can answer some of those, for starters.


- did you say that TV had an image rotation issue though? that would usually indicate a tube problem, loose deflection yoke... or has the whole tube just shifted in the TV frame, that wouldn't matter if you're taking it out of the TV anyway.


The 54cm tube would have different mounting hole spacings for starters so it might not physically fit the arcade machine, after that the critical issue is whether the two tubes use the same socket on the neck board. You can check that just by unplugging one and if they look the same, trying the other (with power removed of course). I can see you have already discharged / disconnected the EHT High Voltage lead so that's good.


If those CRT sockets are the same next is to check the tubes use the same heater and G1 voltage. There are some tube cross references, the one I recently heard of lists the original tube:




but not the other as I think it's based around tubes more commonly found in the US, so a bit of searching should come up with the specs for the 'new' tube to see if those details are the same.


If that's all compatible, the final thing to check is the resistance and / or inductance of the Vertical and Horizontal deflection coils, comparing one tube to the other.


When you unplug the deflection connector from the chassis you can check the vertical coil (usually green and yellow wires) and the red and blue wires are usually the horizontal deflection.


generally speaking, some CRTs have a low impedance (low resistance and inductance) coils while others have higher impedance coils. The chassis is designed to suit one or the other.


So if the readings are not very similar from one tube to the other the chassis would either need to be modified or replaced with a model designed to suit the other CRT.


If you have a multimeter which can measure inductance that's ideal but otherwise measuring the resistance of each coil should give you enough indication if the coils on the two tubes are similar or not.


To sum up, If everything about the two tubes is similar that chassis should work with the either CRT otherwise the easiest is to try to obtain a chassis that does suit the new CRT or just keep looking around for another TV (or just a tube) which is compatible with the original one.


And if in any doubt, wait / feel free to ask more questions, best to play it safe.


Hope this helps, regards John

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OK the pins on the neckboard are a different count, 7 +1 on the 'new; tube and 9 +1 on the Samsung. So no go anyway, dang.


I'm used too measuring continuity and voltage with my Fluke multimeter but not impedance.

I took some readings from the RGB wire terminals in the connector on the Samsung

- Red/Blue have no resistance (0 OHm)

- Green/Yellow sit around 60 Ohm


On the TV the RGB connector wire terminals

- Red/Blue have no resistance (0 OHm)

- Green/Yellow sit at 9.5 Ohm


Anyway it all means naught, cause I'm not going to bother with the $10 TV at this point it goes to recycle (unless someone wants to reconnect and use?) and I'll keep the Samsung tube hoping one day I'll find convergence rings and someone capable to replace them, or I find a replacement tube the same (cheap). I MAY consider buying another tube eventually. Money just better used elsewhere right now.

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Hi, not to worry, that tube did seem to be unlikely to work with the existing chassis, just guessing by the neck diameter.


Those readings for the deflection coils were probably going the right way as the resistance across the horizontal coils is probably just a couple of Ohms, you'd need to use the lowest range and first check the resistance of your meter leads by holding them together, then measure through the coil and note the extra resistance - measuring inductance rather than resistance would give a more significant reading but the main purpose is to make the same measurement on both tubes and see if they read the same or nearly so.


60 or so Ohms for the Vertical coil is similar to a couple I've measured here and yes, it would need to be disconnected from the PCB to get an accurate measurement but it doesn't matter now anyway.


Don't throw out the original tube just yet, I'll try and get a set of convergence rings together for you if I can. Regards, John

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Sorry this took so long, I needed time to get to it.

The underside square chips looks in pretty bad shape, I can't get a better picture so no idea if you can make something of it.

Underside_Chip.thumb.jpg.6dd023ecd6c2d330fe3fd58dd75a0f7f.jpg The top ones:

Top_Chip2.thumb.jpg.10bf8db5eaa2df4497ab93e60e681286.jpg Top_Chips.thumb.jpg.332809ef91064d2b06e0c164a706bc06.jpg

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