kikaso
Enlightened
Yoke and tube specs for monitors
- Thread starter nem
- Start date
trashedcabs
Grand Master
Bit of a bump--anyone happen to have yoke readings for the Kortek KT-2914F? I found resistance online (Rh .5ohm Rv 3ohm) but not inductance.
I tried to run a PB9929 and his Yoke on Matsushita Flat tube from pfx combo. I have a good picture but with very high contrast (closed to white screen). The contrast level is blocked at 200, and impossible to move it.
Any idea to succes to transform it combo mathsushita/Toshiba please.
The Toshiba MCU seems to have a bug where it corrupts the I2C EPROM, and when this happens it corrupts the contrast value so you cannot change it. See this thread for the fix: https://www.arcade-projects.com/threads/toshiba-pd1843-15khz-dim-image-low-brightness.26132/I tried to run a PB9929 and his Yoke on Matsushita Flat tube from pfx combo. I have a good picture but with very high contrast (closed to white screen). The contrast level is blocked at 200, and impossible to move it.
Any idea to succes to transform it combo mathsushita/Toshiba please.
You basically take the I2C EPROM off the I2C bus when you power on the monitor, the MCU will then load default values. Then you put the EPROM back on the I2C bus while the monitor is on and re-write all the saved values. This should overwrite any corruption and fix the stuck contrast.
itsmedario
Enthusiast
Hi All,
Does anyone know if Wells Garden tubes are compatible with a 2930?
I'm looking to swap out a broken tube and am looking at any and all options right now.
Not sure if it matters but John from PNL can do a yoke swap for me if necessary.
Please and thank you
Does anyone know if Wells Garden tubes are compatible with a 2930?
I'm looking to swap out a broken tube and am looking at any and all options right now.
Not sure if it matters but John from PNL can do a yoke swap for me if necessary.
Please and thank you
PapaBergsy
Beginner
Hi Guys,
Does anyone know if a Sanwa PFX 1755 Tri Sync chassis will work with a Nanao MS2931 yoke on a pure flat Thomson tube? From all my research , it has been reported that the Sanwa PFX Yokes and Nanao yokes from MS9 , ms2930,31 etc have a similar horizontal inductance so should be fairly compatible. Just thought I would check here if anyone has done a similar swap or test . I have a Naomi Universal clone cab that came with a pure flat tube and a Wei ya 429 H chassis which looks pretty bad, so would like to rip that chassis and yoke out and put something else in there. I know the Thomson tube isn’t all that great. Thanks all for any guidance or advice .
Does anyone know if a Sanwa PFX 1755 Tri Sync chassis will work with a Nanao MS2931 yoke on a pure flat Thomson tube? From all my research , it has been reported that the Sanwa PFX Yokes and Nanao yokes from MS9 , ms2930,31 etc have a similar horizontal inductance so should be fairly compatible. Just thought I would check here if anyone has done a similar swap or test . I have a Naomi Universal clone cab that came with a pure flat tube and a Wei ya 429 H chassis which looks pretty bad, so would like to rip that chassis and yoke out and put something else in there. I know the Thomson tube isn’t all that great. Thanks all for any guidance or advice .
Who is reporting this? Someone just attempted this on AO too:
https://forum.arcadeotaku.com/viewtopic.php?p=576610#p576610
MS293* are all 0.200mH horizontal.
PapaBergsy
Beginner
@nem thanks for the detail here, it’s much appreciated . you have saved me some time and pain messing with the blast yoke if I go this route with a Sanwa PFX. I feel like when browsing multiple forums I did read someone else’s comment that the blast yokes are fairly close and should work but this is not correct as you have pointed out. Also I should never listen to Google AI, also summarised and suggested it would work. I’m going to hunt for a Sanwa PFX yoke, there is one on Yaton. Or hunt for a chassis and yoke more suited to pure flat tubes. Open to any advice. Cheers.
Update: I read that someone used an MS9 yoke , not the ms293x yoke , but looking at some yoke specs you have posted previously , whilst the horizontal inductance is close the vertical seems bit far off? . I do have an ms9 yoke spare but probably best if I just buy a Sanwa PFX yoke. Yaton Arcade has one on the site now but it came from a differnt sanwa chassis , however seems fairly close to the PFX chassis yoke requirements so maybe that’s my best option ? The tube in this cab is a Thomson A68EMN021X001.
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trashedcabs
Grand Master
Just because a yoke is electrically compatible with your chassis doesn't mean it will give you an acceptable image on your donor tube. They are all designed to match the face curvature and bell shape of the tube they shipped with. It's likely you won't get good purity or convergence without substantial tweaking, or not at all.
IMO, you're better off sourcing a tube that's more likely to be compatible with a yoke in the range for the chassis you're trying to run.
PapaBergsy
Beginner
@trashedcabs appreciate your input also. Thank you. I think I have a bit to think about before taking the plunge on anything after discussing further with you guys . I’ve attached some pictures of the current cab in question , in case anyone is interested.
There is one other option I’m considering which I know you guys might frown upon here , but would love to know your thoughts on putting in a 29 inch consumer TV set.
An example would be a late model pure flat LG , Samsung or Sanyo 29 inch set which generally have smaller chassis inside that could fit in cabinet. They won’t have RGB but most come with component so I could use a transcoder etc. that would be the easiest swap without messing around with yokes , chassis etc. but it won’t be on par with the flexibility of say a tri sync arcade chassis pairing. Thanks guys.
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trashedcabs
Grand Master
Your tube has a bonded yoke, you wouldn't have been able to easily do a yoke swap anyway.
Not sure if you have 100hz sets in Australia, but those typically have yokes which will work with the horizontal .300mH range of chassis (PFX, MS9 etc). We never got them in the states but most of the developed world did.
HD/progressive scan sets will also have yokes that work.
Could also just try and find a full cabinet with a monitor you want, then pull that new CRT out and chuck an LCD in and resell it (or crowbar it, if the game was cheap and shitty enough). I do this from time to time if it makes sense.
Not sure if you have 100hz sets in Australia, but those typically have yokes which will work with the horizontal .300mH range of chassis (PFX, MS9 etc). We never got them in the states but most of the developed world did.
HD/progressive scan sets will also have yokes that work. Could also just try and find a full cabinet with a monitor you want, then pull that new CRT out and chuck an LCD in and resell it (or crowbar it, if the game was cheap and shitty enough). I do this from time to time if it makes sense.
PapaBergsy
Beginner
Your tube has a bonded yoke, you wouldn't have been able to easily do a yoke swap anyway.
Not sure if you have 100hz sets in Australia, but those typically have yokes which will work with the horizontal .300mH range of chassis (PFX, MS9 etc). We never got them in the states but most of the developed world did.
Could also just try and find a full cabinet with a monitor you want, then pull that new CRT out and chuck an LCD in and resell it (or crowbar it, if the game was cheap and shitty enough). I do this from time to time if it makes sense.
Thats a very good point RE the Bonded Yoke, I’ll be honest I have never had to remove a bonded one but imagine it would require some extra time and effort to get it off. Thanks the tip RE the 100hz sets, sometimes a couple do pop up but mainly in the widescreen variation these days. I just sold a Loewe 100hz 68cm set recently but there is no ring set etc on that yoke it’s all set from factory so I don’t think it would have been suitable anyway if I needed or wanted to adjust anything…Your tube has a bonded yoke, you wouldn't have been able to easily do a yoke swap anyway.
Not sure if you have 100hz sets in Australia, but those typically have yokes which will work with the horizontal .300mH range of chassis (PFX, MS9 etc). We never got them in the states but most of the developed world did.
Could also just try and find a full cabinet with a monitor you want, then pull that new CRT out and chuck an LCD in and resell it (or crowbar it, if the game was cheap and shitty enough). I do this from time to time if it makes sense.
. Appreciate all the advice , I’ll way up my options a bit more and report back to you guys here. 
.trashedcabs
Grand Master
I just sold a Loewe 100hz 68cm set recently but there is no ring set etc on that yoke it’s all set from factory so I don’t think it would have been suitable anyway if I needed or wanted to adjust anything…
You don't need to. If the TV's yoke is electrically compatible with the chassis you're looking to mate with it, then you literally just crimp on the right connector and plug it in. That's the point of using the 100hz set, the yokes are compatible with the chassis you're trying to use.
Do we have different terminology here? You can just pull that yoke off. It's been glued on where the plastic screws are.
Instead of a yoke ring set it just has a single ring that has been magnetized at the factory. It's some magnetic ceramic material, and it should break off pretty easily just by prying at one end with a flat head screwdriver.
Do I suggest doing this? If it's destined for the dump, sure why not, if it's usable as is, no.
PapaBergsy
Beginner
Learning so much here just by chatting to you guys about all this. Whilst I have a couple of cabs I’m still fairly novice and still learning all the time, so thanks for the guidance / advice. 
trashedcabs
Grand Master
RepairGuy95
Champion
Can someone explain the significance of why the horizontal inductance really matters but the vertical inductance doesn't, and can be changed via resistor if needed?
Horizontal inductance determines the time it takes to move the electron beam from left to right on the screen. This time is much faster than the time to move the beam vertically. It is the load for the flyback and horizontal output transistor. Me nor changes can be made by varying the ssweep capacitors. Typical values are as follows: if vga or higher (31khz and up) expect around 0.2 mh tri res expect 0.24 to about 0.3mh medium res (24.3khz) 0.34 to perhaps as v high as 0.8 mh standard res typically call .95 to 2.0. Anything other than this may cause excessive load on the horizontal circuit ( specifically the Hot). Hope this helps. If I find out how to post a spreadsheet I have created one with manny differen tube and yoke combinations.
Hope this helps
Rick Nieman
Btw I have been in this business for over 35 years and happy to help!!
Hope this helps
Rick Nieman
Btw I have been in this business for over 35 years and happy to help!!
RepairGuy95
Champion
That helps immensely and makes more sense.
I'd love to see the spreadsheet if you can, would be great to know what can be paired. Knowing I mostly only need to match horizontal is very helpful.
I'd love to see the spreadsheet if you can, would be great to know what can be paired. Knowing I mostly only need to match horizontal is very helpful.
RepairGuy95
Champion
Might you know if the yoke from a nanao ms8/9 will fit properly on a nanao 2930/31/34 tube?