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BuddyC

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Calling all monitor gurus!

I got a New Net City with at Toshiba PF D29C051 tube and Toshiba PD1843 chassis.
All in all the screen looks great, but has some annoying credit burn inn...
Only viewable on a white screen, but still annoying as fuck...

I can get a hold of a totally burn free tube from a Sega Naomi Universal with a Toshiba A68KJU96X tube. Screen looks great in 31khz!

Would a tube swap be possible? Maybe even just swap to the tri sync chassis?
 

rewrite

Multi Boyz Litigator
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Measure the yoke impedance on both. That'll give enough info to tell whether you can swap just the chassis over or not.
 

BuddyC

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Thanks @rewrite!
Got any good links or guides on how to properly measure the yoke impendance?
 

dewmansnk

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Reading though this thread:

https://www.arcade-projects.com/for...igh enough focus voltage for a perfect match.
 

nem

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If it's from a Naomi Universal it's mostly likely a MS2932, which would mean it's a 0.200mH yoke. Tosh PF needs 0.300mH.

I'm not sure if you can drop the yoke from the PF on to a curved tube like the KJU96X and have it look good.

I'm all for scavenging tubes out of television sets, but if you have a working, nice looking arcade monitor, IMO keep it as is.
 
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Hatsune Mike

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Always remember that one tube model dose not guarantee the same yoke type or specifications as another. A68KJU96X has been seen with a 0.2mH horizontal yoke as nem has mentioned, 0.3mH with a typical MS9 yoke, and around 0.38mH IIRC for the MS8.

The Toshiba PF chassis (at least some variants) will be more or less fine on an MS9 or D29CR50 A68KJU96X, as the impedance is compatible. However, focus was no good. When installed on the hitachi MS9 tube, with the same yoke impedance, focus was fine, but the heater voltage was too low. I don't have numbers for any of these things. @dewmansnk your takeaways are correct from my memory.

I think the various Toshiba PF revisions might also introduce differences in the heater current. One chassis produced the correct heater voltage on an A68KJU96X while another was too low, IIRC. This was a while ago and I did not take good notes.

I would not try swapping yokes unless you are 100% out of other options.
 

BuddyC

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Yeah... you’re probably right @nem. Thanks for all the input guys!
 

Hedonism Bot 2.0

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@BuddyC I’m doing some tube swap experiments with PF- I was able to get a yoke from Yaton and currently waiting on a chassis. I’m going to be putting the yoke and chassis on a pure flat TV. Whenever the chassis comes in, and hopefully working, I’ll let you know.
 

BuddyC

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Damn it! Have been searching a couple of months for a spare chassis. Never found shit for sale...
Fingers crossed it’s a working one.
 

BuddyC

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Score! Found a Toshiba PD 1843 chassis on ebay. Exactly the same chassis as I have in my NNC.
Bought it just to have a spare, but it got me thinking....

I still have access to a European Naomi Universal with a Nanao MS-2932-s chassis and a Toshiba A68KJU96X tube. Gorgeous burn free tube, but 31 Khz only. The plan is to buy a retro scaler from @invzim, but would be fun if this was a drop in replacement 8)

Would the Toshiba PD 1843 be a drop in replacement for the Nanao MS-2932-S or would the bastard explode and melt my face?

Tri-sync goodness in a burn free Naomi Universal would be sexytime....

Please chip in Master@'nem' and Master@'Hatsune Mike'
 

nem

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Won't work, different inductances. 2932 is 0.200mH, PD1843 0.300mH.
 

invzim

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I still have access to a European Naomi Universal with a Nanao MS-2932-s chassis and a Toshiba A68KJU96X tube. Gorgeous burn free tube, but 31 Khz only. The plan is to buy a retro scaler from @invzim, but would be fun if this was a drop in replacement

Would the Toshiba PD 1843 be a drop in replacement for the Nanao MS-2932-S or would the bastard explode and melt my face?
If there was a drop-in replacement for that tube, there would be no retro scaler. I went to quite some lengths to do this, even bought an experimentally modded chassis of grantspain who can probably be considered god-like when it comes to Arcade monitors. I didn't quite look right with skewing and generally bad picture quality.

Don't take my word for it though, but I'm fairly certain it's a no-go because of the inductance and resistance of the tube.
 
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Hatsune Mike

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If you yoke-swap with an MS9-29, you can run a PFX chassis on it, or an MS9-29 if you only want 15/24khz.

As is, though, that yoke isn't going to cooperate with the common tri-sync chassis, Going by impedance you might get a Wells-Gardner D9200/D9800 chassis cooperating with it.

Or, I wonder, if you could simply put a 0.1mH inductor in series with the horizontal deflection wiring, at the possible expense of width.

Anyway, your main obstacle with the Toshiba PF chassis is that the focus voltage doesn't seem quite high enough for the A68KJU96X and short of generating a new focus voltage (thousands of volts) I don't know how to solve that one.
 

BuddyC

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If there was a drop-in replacement for that tube, there would be no retro scaler. I went to quite some lengths to do this, even bought an experimentally modded chassis of who grantspain can probably be considered god-like when it comes to Arcade monitors. I didn't quite look right with skewing and generally bad picture quality.
Don't take my word for it though, but I'm fairly certain it's a no-go because of the inductance and resistance of the tube.
Looks like you are getting a sale soon buddy! :D
 
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