Nanao MS9 to Wei Ya 3129A Chassis Swap Guide

Post by **grantspain** » March 6th, 2009, 11:22 pm

ok getting somewhere now,for a moment is it possible to move the cabs completely away from each other but use the same way you have the electricity connected,i am trying to prove whether this is noise related

dmauro · Post by **dmauro** » March 7th, 2009, 7:23 am

I can't move them away from each other (not at all easily) because I have some cables running from one to the other. But I can turn the other cab off and the noise goes away completely. Pulling them apart a few inches seems to helps a little bit as well (I had them butted directly up to each other before).

Post by **grantspain** » March 7th, 2009, 9:38 am

dmauro wrote:I can't move them away from each other (not at all easily) because I have some cables running from one to the other. But I can turn the other cab off and the noise goes away completely. Pulling them apart a few inches seems to helps a little bit as well (I had them butted directly up to each other before).

we are really getting somewhere now,what cables are you running common to each cab because one of those is picking up mains noise is causing an earth type interference
are you using one video source for both monitors??

dmauro · Post by **dmauro** » March 7th, 2009, 8:34 pm

Well the monitor in the cab that is causing interference wasn't even receiving video, it was just on (but I tested and the interference happens even when the other monitor is receiving video from another source). The cables that are being run between the cabs are 2 x USB cables, 1 x Playstation controller cable, 2 x VGA cables (one for the monitor, one for the PC), 2 x 3.5mm stereo cables. I tested the monitor in and out of the cab with the wires in the same location, so it's got to be the location of the monitor itself in relation to the interference. The monitor isn't really at all close to any of these cables that are running between the cabs, and it's just the video cable that could be picking up interference, but as I said, I tried it going out the front also so that it wouldn't go past any transformers or anything.

I wish I could just borrow a lead blanket from the dentist's office and just very easily prove/disprove that it's the monitors being next to each other that's causing the problem.

edit: I've got the cabs several inches apart and the noise is pretty minimal right now. I'll probably just leave this how it is. Just had some friends over for a gaming session, and nobody even noticed it. Most of the time only one cab will be on anyways.

NachosRlue · Post by **NachosRlue** » March 10th, 2009, 8:32 pm

Hey guys, first time poster here. I am glad there are others out in the world with the same love for these cabs.

Question: Is replacing the chassis the best/only way to go about fixing these monitors? Does the new chassis yeild a better picture, or are the parts on the Nanao chassis impossible to find? I don't know much about fixing monitors, but looking at the board, there does not seem to be that much to them.

I'm sorry if I missed somthing. I just bought a second Blast city, this one with a non-working monitor(with the black goop). I am unsure how to proceed.

Post by **grantspain** » March 10th, 2009, 8:47 pm

blast city are fitted with nanao ms2930 or ms2931,no one has ever really got to the bottom of the black gloop of death-or not informed anyone anyway-the train of thought seems to revolve around the gloop is nothing more than the insulation of the horizontal drive coil or bridge coil that overheats and leaks but the actual fault is the flyback transformer
the flyback transformer is not available for these chassis as far as i am aware
i would love to get my hands on one of these monitors to find out one day really what is happening.
your alternatives on the chassis front are solely the rodotron 666b or wei ya 3129b,results from these are mixed and never as good as the original nanao
if you intend to run different res games then go the replacement chassis route,if you intend to run 15khz only then i would consider just getting a complete monitor-if doing so you will need to match the curvature of the tube to the bezel

dmauro · Post by **dmauro** » March 11th, 2009, 1:56 pm

I do have two Nanao chassis available now though. Not sure if I should hold no to one just in case (I imagine they are kind of tough to get a hold of), but I could probably sell you one if your monitor uses the same chassis. (edit: Grantspain says you need the Wei Ya 3129b and I used a 3129a, so this chassis probably wouldn't work with your tube)

Post by **grantspain** » March 11th, 2009, 6:51 pm

the nanao ms8 and ms9 range use a 0.300mh horizontal yoke whereas the later chassis use a 0.195mh horizontal yoke,if you use a ms9 on a ms2930 yoke then it will work for a short time and then either burn out the yoke or the entire deflection circuit of the chassis
this is why it is very important to match a chassis to the yoke

NachosRlue · Post by **NachosRlue** » March 11th, 2009, 8:10 pm

Thanks for the help guys, but how do I know what chassis I have? I tried ot match it up on this site ( http://www.jomac.net.au/mon.htm ) but I could not find one that looks like mine. I could put up a picture later.

I have a friend that specializes in TV repair, he is helping me try to figure out what is wrong it. If we make any progress I will let you know.

If I can't get anywhere with a repair, I'm looking at a new chassis or a new monitor

Post by **grantspain** » March 11th, 2009, 8:13 pm

yeah a photo would help but also important to note the ms2930 was a manual switchable frequency chassis whilst the ms2931 was an automatic digital with osd
you can tell by the remote board(the adjustment control board in the cp area)

Xenepp · Post by **Xenepp** » March 12th, 2009, 1:21 am

dmauro > I will have a non-working chassis in the next few days, if someone wants to take a look at it for you then I'm happy to let it go for postage costs.

-Joel

NachosRlue · Post by **NachosRlue** » March 14th, 2009, 3:31 am

Alright, I think I have the ms2931. It switches frequency automatically, it has an OSD and a remote board, and best of all it has a placard right on the tube that says ms2931, if I had just looked

Thanks for the help so far, my friend and I are still trying to figure out why the Nanao chassis are not working. We have not had a lot of time to work on it lately, hopefully we will know what the problem is soon, even if it can't be fixed. On that note, does anyone know where I can get a schematic for that chassis?

Post by **grantspain** » March 14th, 2009, 11:40 am

i am gonna get on to sega next week to see if they will give me every schem/manual all the way back to ms8 chassis-about time they helped out the fellas that fix all their gear

dmauro · Post by **dmauro** » April 16th, 2009, 4:45 am

I still haven't quite gotten over that noise issue I was having with one of my monitors. I thought it was gone, but it's been coming back lately and it seems to happen when the monitor has been powered on for a while. The noise I've been getting is like this in varying degrees. There does also seem to be some slight interference caused by the other monitor, but I've been able to reduce that, and I can turn that one off and this other noise persists. The odd thing is that sometimes it can get really bad and when it's really bad (like in the video) physical trauma to the cab gets a reaction out of it. If I give the cab a little hit with my palm, I can see it in the noise on the monitor. Sometimes it will even get rid of the noise (or at least drastically reduce it). I played around with the dag earth, but the connection still seems to be solid and it's hooked up to the proper ground connection on the neck card. This is really getting to be pretty bothersome. Any more ideas?

For reference, here is what it looks like when the noise isn't quite as bad, but definitely there. Also, sometimes leaving the monitor off for a few seconds gets rid of it.

edit: This started happening more frequently again after rotating the monitor to the horizontal position. I guess I'll just get it back to vert and see if that affects it positively.

dmauro · Post by **dmauro** » April 26th, 2009, 5:22 am

I've got the monitor back in vertical orientation, and I've noticed the noise settling into a pattern. It comes in after the monitor has been on for about ten minutes or so, and then it lasts for a few minutes, and then it goes away and doesn't come back.

Post by **andygeezer** » April 26th, 2009, 8:13 am

grantspain wrote:i am gonna get on to sega next week to see if they will give me every schem/manual all the way back to ms8 chassis-about time they helped out the fellas that fix all their gear

Good luck with that one, blood and stone spring to mind..

Post by **robotype** » April 27th, 2009, 11:33 am

looking at the yoke connectors it looks like an MS9 not MS8, what is your crt make and number?

dmauro · Post by **dmauro** » April 27th, 2009, 3:24 pm

That's funny, astrocitizen was thinking of buying my chassis and I sent him a pic and he said the same thing. I'm going to check out the tube and chassis and I'll post some model numbers.

dmauro · Post by **dmauro** » April 29th, 2009, 2:31 am

Where on the chassis do I find the model number?

Post by **robotype** » April 29th, 2009, 7:52 am

you don't find it, just look at the pictures at jomac

the crt usually have a sticker on the back with a code
for example A68KJU96X (4K) is the code I found on astro city toshiba tubes with ms8 chassis

Nanao MS9 to Wei Ya 3129A Chassis Swap Guide

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