New tube needed for Nanao MS8-26U

[Zebidee]

Hi folks,

I've got a Nanao monitor (MS8-26U) with a broken tube!

Here is the story:

Originally, the chassis worked great, 100%. I installed the monitor into a Neo-Geo cab.

However, I did something very dumb. All the electronics were perfect, but I stupidly forgot to secure the tube properly into the frame and, when I moved the cab onto into a truck, the tube moved out and the narrow neck got broken. So now I find myself in the market for a replacement tube for this Nanao chassis.

The chassis is in top working order. In fact, I had just overhauled the capacitors.

To overcome my stupidity, I hope to replace the tube with an old TV tube. There will be some trial and error I guess, but can anyone advise on which TV brands I should focus on? I know that Toshiba & Hitachi are good tubes to target for this. Are there any others? For example, what about Panasonic & NEC tubes?

Grateful for your advice, oh gurus of arcade monitors out there  ...

[grantspain]

the nanao ms8-26 has a wierd yoke so if you do find a donor tube you will need to perform a yoke swap also

[Zebidee]

Thanks Grantspain!

The original tube was:

Mitsubishi A63JHF81X (26 inch)

[SirPeale]

Mitsubishi A63JHF81X (26 inch)

25".  The A63 denotes this.

[lilshawn]

Mitsubishi A63JHF81X (26 inch)

25".  The A63 denotes this.

(viewable) 

[Zebidee]

Even though 63cm divided by 2.54cm (1 inch) = 24.8 inches, Nanao seem convinced that A63 means 26" and this is reflected in the model no.: Ms8-26U.  If it were up to me, I'd call it a 63cm tube & be done with it.

[SirPeale]

Anyway...you want a tube number that starts with that.  Use the B&K tube compatibility chart to find a match.

[Zebidee]

Peale: Soooooo, how does one make sense of the B&K tube compatability chart? The numbers don't match the tube numbers, and I don't know how to read this unless one has a B&K tube tester.

Do you mean this one?

http://bama.edebris.com/manuals/b&k/700tubes/

[SirPeale]

Basically,  you look up your existing tube and check the adapter number.  Then check your replacement tube and see what adapter it uses.  If they match, there's a good bet it's a fine swap - at least in terms of the tube.  The yoke is another story.  You'll have to Ohm out the yoke to see if it's compatible.  If it is, you don't need to swap it out (though you will likely have to swap out the connector).  If not, you'll have to swap the yoke.

There are many docs on this across the internet.  Google is your friend.

[Zebidee]

Basically,  you look up your existing tube and check the adapter number. 

Excuse me Peale, How do I do this? Pretend I am an educated lay-person, even though I have quite a bit of experience with arcade monitors.

I assure you not stupid, and I googled this extensively but it did not break my brain block on this.
I just don't understand how the tube number A63JHF81X relates to any of these adapter numbers like "1EL3" etc.
Do I need to find some other number? Please help me understand this.

[SirPeale]

The doc on the site you linked to wasn't what I thought it was.  Until I read it, I though it was something like this:

http://arcarc.xmission.com/PDF_Monitors/FAQ%20-%20CRT%20Cross%20Reference%20Compatibility%20Chart.pdf

match the tube number to the adapter.

[Zebidee]

Thanks Peale, but this is still clear as mud.

What I really need to know is what TV brands, even models, are likely to have tubes to match my Nanao monitor chassis. Any advice welcome.

[SirPeale]

It's a crapshoot.  Good news is that /most/ 25" tubes you find in TVs will work okay.

[lilshawn]

this list is what your ACTUALLY looking for.

http://www.bkprecision.com/support/downloads/pdfs/CRT_Setup_Chart.pdf

your tube #A63JHF81X uses a #23 adapter and the heater is 6.3 volts.... any other tube you find that is:

the same size... 26 inches
when looked up in the B&K list uses a #23 adapter
and uses 6.3 volts on the heater....

would likely be a good candidate for swap.

[Zebidee]

Ahh, that makes a lot more sense. Thanks for the link.

I'm on the lookout. Just went to the local 'Revolve' place and found only TVs with 51cm & 68cm tubes. In fact, A63 is a pretty rare size for TVs. Having said that, I've got a A63 sized Grundig TV (SCART input) mounted into one of my cabinets so they do exist. If I was truly desperate I could trash that TV and take the tube, but it would be a waste.

Keep on looking ...

[SirPeale]

this list is what your ACTUALLY looking for.

Thanks Shawn, that's what I meant to post.

[lilshawn]

this list is what your ACTUALLY looking for.

Thanks Shawn, that's what I meant to post.

lol! actually, i was looking for it before since the manual i have for the rejuvenator is old as dirt. so i already knew what i was (and you) where looking for since i needed it.

[Beretta]

Basically,  you look up your existing tube and check the adapter number.  Then check your replacement tube and see what adapter it uses.  If they match, there's a good bet it's a fine swap - at least in terms of the tube.  The yoke is another story.  You'll have to Ohm out the yoke to see if it's compatible.  If it is, you don't need to swap it out (though you will likely have to swap out the connector).  If not, you'll have to swap the yoke.

There are many docs on this across the internet.  Google is your friend.

been a while since i posted here, my project came to a screeching halt do to RL.

anyhow im still on the look out for 19inch tubes.. keep coming up with 20inchers, people claim they're 19inch.. i think most just dont realize there was such a thing as 20 or 21 inch tv's, but i dont find that out till 've already went to pick them up.

anyway to my question assuming im able to finally hunt down an elusive 19inch tube exactly how close do the yokes need to be in order to avoid swapping.. i dread the thought having to do that.

[grantspain]

totally ignore whether its 25" or 26"-read the crt label A66XXXXXXXX,that gives you the exact size and match to that
the yoke on a ms8 will completely different to pretty much anything else out these as its a .300mh

[Zebidee]

I ended up getting an A63ADTXXXX from a not-so old NEC TV.

I was prepared to do a yoke swap, but after I opened up the back the bonded yoke (i.e. yoke glued down, no convergence/purity rings) stopped me cold for a bit.

Then I proceed to carefully pull the bonded yoke off - using a hack saw at some points. As you would expect, I was very careful.

Just when I was finished, I got zapped by the anode! When I reached down to remove bits of the old destroyed yoke I picked up some copper wire bits, the other end of which passed vaguely close to the anode hole .... muscle spasms in my forearm but I am OK ... This happenned even though I had discharged it prior (charge builds up over time!). Might have been a lot worse if I hadn't.

I installed the original Nanao yoke onto the TV tube and cribbed the convergence/purity rings as well. I set it up in a sort-of monitor frame that I just happenned to have lying around, and hooked it up to a portable JAMMA power supply & harness that I also just happenned to have lying around. Then I set up a spare Mame-d PC that (you guessed it) I just happenned to have lying around, and I ran a test signal. Sheeeeesh, that looked bad. But it had a recognisable blur of windows there so I fiddled with the yoke a bit until it looked kind-of OK and I could start a proper test signal (I used the old Nokia tool, NTEST.EXE)

Anyway, eventually and afer many curses I had the yoke installed and the convergence as good as I could possibly get it ... then stuffed it up by moving the tube and had to do it all again (tip: use polyurethane glue to secure the little rubber wedges under the sides of the yoke). I took lots of photos that I may upload sometime. Anyway, I put the monitor into the original cab and it looks fine, 97% as good as the original.

I just sold the cab, made some $$$ and free space in my shed! Oh, and now I know how to swap a yoke as well 

Thanks everyone!

[grantspain]

i would like to see some pics of screen shots and test grid if pos

[Zebidee]

I didn't take a photo of the screen with a test-grid on it in the final position final .

This is a photo of the testgrid from when it was kind-of looking OK. You can see it is still quite out here, especially in the lower third of the screen.

[Zebidee]

These two pics were taken after getting the convergence as good as I could get it, within reason.

These photos were taken of a relatively still moving image, but a careful eye will notice that the convergence is still a little out towards the lower right corner. However, I decided that it was good enough to live with.

[grantspain]

it looks a total success,maybe a couple of convergence strips would have bought in the lower corner but in all i think it worked very well

[lilshawn]

for a swap, this is couldn't have been better. (minus the getting zapped part been there done that)

convergence is always a PITA and you always get a corner that's out. Oh well, once you out video to it, you don't notice anyways.
 

[ac3]

Very interesting read, I've read quite a few tube swap guides as I plan to do it myself some day as I have quite a few bad tubes building up. One thing no one ever seems to mention is how careful you have to be when adjusting the yoke. I know you adjust it when the monitor is turned on but doesn't the yoke have some rather high voltage going through it? do you have to be careful not to touch the wire/winding?.

ac3.

[lilshawn]

don't go crazy or anything, but for sure, there can be some pretty hazardous voltages in and around the area. if your feeling nervous, just wear gloves  . but no, so long as the insulation on the yoke is good, and there is no electrical issues with the chassis, you should be okay with touching it. you just have to watch out for the prongs where the red blue yellow green wires solder on to the yoke, as often they are exposed.

for sure, you can do it, by powering down the monitor, doing the adjustment, then powering it back up again, but it would take a REALLY long time to do it.

the hardest part is making sure the yoke is on straight and even on the tube, if it's crooked a little, your image will be too. once it's on there, you can work the magnets on the neck to get it good and lined up.

head over to wellsgardner and download the service guide for the k7500 monitor, it has a really good explanation on how to setup tube convergence in it. " cheat link:----> http://www.wellsgardner.com/pdf/Service/K7500.pdf it starts on page 5

[ac3]

Thanks for the info lilshawn.

[Zebidee]

UNfortunately, you have to do the adjustments while the monitor is warmed-up, otherwise they can be counter-productive! You should let the monitor stay on for 10 mins or so before making adjustments.

Gotta say that the most important thing to have when adjusting a monitor yoke is a LOT of patience. Be prepared to go away for a while and come back when your frustration levels have gone too high.

Other things to have on hand are:

- some of those little rubber wedges for the yoke positioning
- tiny magnets (which I have pulled off other tubes)
- some *polyurethane glue* (for keeping everything in place once you get the yoke right - other glues may cause problems).
- a good mirror (to save your thighs from constantly squatting to adjust and getting up to check).

[BurgerKingDiamond]

ugggh. This process sounds so frustrating. I have a perfectly good chassis laying around. But it will probably be a long long time before I ever get the motivation to find a tube for it.

It's funny. I called a local "amusements repair" company when I orginally broke the tube. I told them what the problem was and they had me wait for a technician to call me and setup the appointment. The next day the technician called me and said "I don't do that kind of thing anymore"..... I was like well cool man, what do you do? That would have just been too easy!