List of compatible tubes?

[Wurstkopp]

Perhaps another route would be to collectively design a standardised sync splitter circuit built into a little box so that we can just use any 29 inch tv tube and it's *original* chassis in our machines... ?

You don't need a sync splitter, usually a 50/60 Hz TV with scart accepts composite sync. Nonetheless the picture of a Nanao/Sanwa/Tosh/Toei arcade screen is much nicer than a TV.

All you need is to decode the tube reference number for curvature etc and nuber of pins on the neck and swap them over....

So thats it? I maybe try this out. Got a MS9 tube with the deepest burns ever seen. Nothing much to loose.

[emphatic]

Here is an interesting modification done by UncleTom (is a member on here from lovely Sweden): http://hornet.homeftp.net/technical/hellmod/

I've also noticed that Japandeal Webshop has some very cheap neck boards available. I don't have the required space to store spare tubes for these kind of shenanigans, but I would really like to see someone succeed when trying it out.

[uncletom]

Aha, this is a really interesting thread!

When you swap a CRT you always use the yoke provided with your previous CRT. Never trash a yoke. The CRT is part of your monitor's circuit in a different way than the yoke. The yoke is often very customized to the design with all the correct values, impedance and inductance.

You can use a trashed TV that you find in your local recycling terminal. You should look for a 29" CRT, 28" will also work *if* certain parameters agree, like Granspain says; heater voltage and pinout of the CRT neck. Most 28 and 29" CRTs are alike. They often use color-pins (RG and B cathodes) on pins 6,8,11 with G2 on pin7, heaters on 9 and 10. Så you need to check the old neckboard to see what pinout that particular CRT has. In many cases there is print on the neckboard that states the pin functions. Or you can check pins 6,8 and 11 to see where they go. Cathodes have fat resistors and a transistor before them, sort of a final amp-stage to the color guns. Easy. There you have your colors. If you cannot switch on the TV to measure the heaters, you can hope that your MS9 chassi has it correctly. However, if there's too much glow in the neck, you can change the resistor on the neckbord to lower och boost that voltage. Normally there is only 6,3 or 12 Volt to the heaters. I think usually the 29" CRT has 6,3V.

I didn't know that C-grade tubes existed. How is the picture quality?

[penrhos]

I've bookmarked a few websites for tube/yoke swaps that provide good info..

http://www.ionpool.net/arcade/tubeswap/tubeswap.html

http://www.8liners.com/datatech/monitor.html

http://arcadecontrols.com/files/Miscell ... crtfaq.htm

http://www.coinop.org/repair/Monitor_Tubeswap.aspx

http://www.arcaderestoration.com/

Anyone got the tube reference decoding key?

I know A68 = 68 cm = 29" A63 = 63 cm = 25" - I know some of the other numbers describe the pin layouts & heater voltages.

[Wurstkopp]

Good infos, guys. So if I'm correct you first have to have the same deflection angle like the old crt, I think the MS9 has 90 degrees. After that you have to check if the crt necks are equally wired and measure the heaters. Then you exchange the yoke and finally adjust the screen with the purity rings.

Seems not easy but worth a try.

[uncletom]

Ah.. no. 110 degrees you mean. 90 are the smaller CRT, like 19-25 inch. I have never seen a 90 degree 29''. The CRT is often branded, actually relieved text in the main glass bubble that specifies like "110".

And yes, you measure the heater voltage. DC between pin 9 and 10 in this case.

[Wurstkopp]

Ah, I thought the 110 on the back meant the voltage, ok, its the angle. How do you find out about the a,b or c-class tube? I have a III on a spare tube here, does that mean its a c-class tube?

[dieKatze88]

Katze you're just looking in the wrong places. Alva amusements sells that chassis domestically for 180 usd. Not bad right?

Not bad. I might consider that, I've got one of thoes 45 dollar weiya video upscalers, and I don't really care about the 15khz picture if I can upscale it to 31khz with no lag...

[uncletom]

How you know that it's a A, B or C grade tube? Easy. You will know once you see the picture. Then you must decide if you want to keep it.

Typical problems with 'not TV-speced' CRTs are poor convergence, uncurable coloring/magnetizing puity problems, phosphor damages of various sorts, and any other blemishes done by accident in the factory to the material. I thought there were only A and B grades, the C must look really aweful I can imagine.

Also, because the CRT often comes with the yoke attached/glued, any problems caused by a faulty installation of yoke are also considered in the grading of the CRT.

[uncletom]

Hm... "Ah, I thought the 110 on the back meant the voltage" - you don't understand. I meant the reliefed big text on the glass bubble, which is then painted with the conductive paint. Not the 110/220 Volts specifications. In such case ofcourse the lable mentions "Volt AC" or something. Please don't confuse the CRT-degrees with input voltage.

Then again not all CRT have text molded into the glass. I've only seen this on several CRTs. Many CRTs have only smooth glass all around. No text. But still, you can see if it's 100 or 90. Look from profile, compare like a 20" with a 29" CRT you will see the shape difference from both front and side.

[Wurstkopp]

Hm... "Ah, I thought the 110 on the back meant the voltage" - you don't understand. I meant the reliefed big text on the glass bubble, which is then painted with the conductive paint.

I know what you meant. The reliefed text says "29 - 110", so it's a 29 inch tube with an 110 degrees angle. Also there's a big "III" (3) below that. The tube comes from a very expensive broadcast monitor.

[uncletom]

Right.. yes. That should be it. But not all CRTs have this text, so one must rely on the shape of CRT itself. It isn't very hard to spot.

Also, for information on many CRT for which you have no previous neckboard, I use this info. And there you can also see what heater voltages and socket type are used:

http://hornet.homeftp.net/CRT_socket_ty ... oltage.pdf
http://hornet.homeftp.net/CRT_socket_type.pdf

Also, I can confirm that our 29" Toshiba for MS9 (A68KJU96X) has heater voltage 6,3V.

Important also is, that the socket references in these documents are not of any general standard, but only standard for the specific application used in the documents. For instance; "A8" in one document and "23" in the other document means the same. You will need to refer to the socket pinout as K=6,8,11 for short, and specify heater voltage.

[Wurstkopp]

Thanks for that list, dude!

According to the list the Toshiba A68KLF96X02 has the same heater voltage (6,3) and the same socket type (23). Anyhow, I will check if its correct and give the yoke swap a try then...

[uncletom]

That sounds like an interesting project. I think that you will be very successfull.

Now, yesterday evening I measured the yoke of my MS9 (Star Wars Trilogy Upright) and I was amazed that the coils were 7 Ohms, and 0,7 Ohms about. This is very unusualy I think. So please, never trash a yoke. Particularly from a Nanao MS9 monitor.

The MS8 has more of normal values, I think last time I checked it was 30 something.. Ohms and 1,5 Ohms. So "high impedance" yokes, less rare, could be used for MS8.

Also here, important during monitor operation the first time testing is your smell. Always notice any strange smells and be ready to Switch off quickly.

[Wurstkopp]

Why not get a TV tube and do a yoke swap.
All you need is to decode the tube reference number for curvature etc and nuber of pins on the neck and swap them over....
I did one a few years ago and while not perfect it was acceptable.

I'm currently checking for TVs in my region to do the swap but all 29" TVs I found had different curvatures (they're mostly semi flat or real flat). It seems there are not that much super curved 29 inch TVs with 60 Hz out there.

What TV did you take if I may ask, Penrhos?

I think a list of super curved 29" TVs with would be great. Here's what I found:

- Toshiba 2929 DD.