WTF did my monitor just die???

[UberCade]

OK so I'm getting into the final stages of completing my arcade cabinet and tonight is the first time I've even plugged in the monitor, which is a Sanwa 29PFX-A tri-sync. I built a dedicated PC for it which includes an ArcadeVGA 3000 video card, and decided to hook everything up just to test it out and see what it looks like. I plugged in the monitor and it powered up fine, showed the "no input" message on the screen, so I hooked up the PC and fired it up and everything was going great. Everything displayed as it should, I could see the POST message, the Windows desktop showed up fine, and I tested a few games out using the keyboard because my control panel isn't finished. I played a few games: Pac-Man, Galaga, Street Fighter 2, TMNT, etc. and everything was going great, and the picture looked fantastic. I was really excited because I've been working on this thing for a long time and invested a lot of money into it. Suddenly in the middle of my TMNT game, the display turned off, and then started this weird cycle of what sounded like turning itself on and off rapidly and continuously, or like it's switching sync rates or something like that, that clicking sound it makes when it powers up and switches between sync rates. I unplugged it for a few seconds, turned off the PC, and plugged the monitor back in, and even with no PC power, the monitor still does the same thing, rapidly cycling and clicking like it's turning on and off really fast, and eventually I could smell a faint burning smell.   I watched inside the monitor from the back when I plugged it in and there's a big yellow cylinder looking thing on the monitor circuit board that illuminates (I assume from electricity) everytime it clicks, like electricity is passing through it or something.


This really pisses me off, because the monitor is BRAND NEW! Could I have done something to fry it? It was plugged into a regular 110V outlet, hooked up to an ArcadeVGA video card which is supposed to prevent any unsafe display resolutions from being output. It was working fine for about 10-15 minutes while I was playing with it, then it started doing that. I've tried unplugging it and plugging it back in a few more times and it's the same damn thing.   Anybody have any idea what could be happening? Should I just buy a Wells Gardner 9800 since it seems pretty popular among builders?

Something else I've been researching, does a monitor like this need to be hooked up through an isolation transormer, or does it have one built in? I think the yellow part on the circuit board that is lighting up when I plug it in is a transformer. I really have no experience with arcade monitors so I really need some help here.

[atomikbohm]

This really pisses me off, because the monitor is BRAND NEW!

It sounds like you took the proper precauations to make sure you didn't cook it by sending a 31 khz frequency to a 15 khz monitor.  So assumeing that you didn't dump your beer on the deflection board, I would contact the people you bought it from and see if they are willing to repair or replace.  It is still under warrenty ... isn't it?

[MonMotha]

This monitor is a digital tri-sync.  I have (accidentally) confirmed that it will generally shut down if you feed it an out of range signal.  A friend of mine had what sounds like this happen.  He ended up just exchanging it with the place of purchase for another new-in-box one, so I never bothered to troubleshoot it.  His new one (and several others purchased at the same time) have been operating fine since.

Where is the component you are referring to that's lighting up?  Can you take a picture?

[UberCade]

The problem with replacing it is I bought it almost a year ago from a seller on eBay who was selling off some warehouse stock he had left over. It came brand new in the original box, but I bought it before I even started building my cabinet so I haven't even plugged it in until yesterday. Getting a replacement is out of the question because it's been so long, and I don't even know where you can get this particular monitor anymore. If it's somehow destroyed I'm just going to buy a Wells Gardner d9800 or d9200 because at least they're well documented and still supported by the manufacturer. Trying to find any information about the Sanwa 29PFX-A makes you feel like you're the only person in the world who has one because there is literally NO information anywhere on the internet about them. I'll take a picture of the part I'm talking about a little later today and post it so maybe somebody can give me a hint as to what happened. Nothing like 10 minutes of bliss playing arcade games on your cabinet for the first time followed by the premature death of a brand new monitor to ruin your day. 

[UberCade]

OK here is the part I mentioned that is being lit up inside when the monitor clicks and cycles through whatever it's doing:





Seems to me electricity is passing through whatever that is (transformer?) causing it to illuminate from the inside everytime the monitor clicks like it's turning on/off or switching between sync rates. Like I said before it's just a continuous cycle of that when I plug the monitor in. I am decently proficient with soldering so if this is something I can attempt to fix by replacing some parts on the circuit board I want to try, because I'm sure it will cost far less than buying another monitor. I would need help identifying the parts though because I don't know how to identify a diode, transformer, capacitor etc. because I have next to no experience working with electronics at that level.

*EDIT* After doing some reading on the internet, it looks like that part, which is either the isolation transformer or flyback transformer (I think), may be bad, because some symptoms of a bad transformer are a bad smell, which there was a slight burning plastic type of smell when I powered it up, and internal arcing between windings, which would account for the illumination effect, so if that's the case and there's a short in the windings, theoretically if I replace the transformer it may fix the problem, as long as nothing else is damaged? Can I get some input from someone experienced with electronics and repair? I'm hoping it's something simple that I can fix myself so I don't have to get a new monitor.

*EDIT* OK I plugged it in again and watched that transformer and it is arcing internally on the lower portion of the transformer, so that's got to be the problem, or at least part of it, so now I would assume, or hope I can find a replacement part from an electronics supplier either online or locally once I identify exactly what kind of transformer it is and spec it. Has anyone done this type of repair and can offer me some advice? I know I'll have to remove the circuit board from the chassis which will require me to discharge the monitor. I'm also wondering is there some other potential problem that would cause the transformer to go bad or is it just a transformer problem? So far I've been kinda answering my own questions by doing my own research but now that I'm faced with replacing the transformer I could use some advice.

[lilshawn]

transformer + light = not good

that transformer is toast...what your seeing is the transformer cooking on the inside.

what your experiencing is the monitor starting up....loading down beacuse of a problem...and shutting down...then trying again

if you can find someone to fix it i would...i wouldn't attempt repairs if i where you unless your adept in electronics.

likely what this transformer does is supply several different voltages for diferent components around the board.

should you feel the need to replace it yourself, i would like to find out which coil is toast....then figure out what runs off of it... you likely have multiple problems now...

[lilshawn]

P.S. try contacting a sanwa distributer...you may be able to convince them to exchange it for you....if you talk nice. 

[MonMotha]

Sanwa distributor?  I think that particular Sanwa is out of business.  It's not the Sanwa Denshi corp that makes all the joysticks/buttons that people like.  Sanwa seems to be a very popular company name in Japan.

That transformer is on the secondary side of the power supply.  It's not the main transformer between the primary/secondary of the power supply (that's the one near the front with the metal foil strap).  I don't know what that transformer is used for, and I unfortunately don't have or know of a schematic for this, which makes troubleshooting hard.  It looks like it's located near the horizontal yoke output, so it probably has to do with one of the many horizontal shaping controls.  These fancy multisync monitors often have lots of little (and not so little) transformers to couple signals in and out of the horizontal output path.

It may be possible to tear it apart and re-wind it, or one could possibly be stolen off another dead unit (with a different failure, of course).  I wouldn't recommend doing this unless you're fairly confident in your electronics abilities.  Getting a replacement might be hard, though, as I somehow doubt it's a standard part; I'm not getting any hits for the part number.

EDIT: Woah, I actually DO have a schematic for this.  It's really, really hard to read, though.  It might help if you can find the "designator" for that part.  It'll be written on the board near the part and will probably be "Tnn" where nn is a number.

[UberCade]

I wouldn't even know where to begin to find a Sanwa distributor, so I think that option is out. Information regarding this monitor is so scarce, which is ashame because the image quality, for the 10 minutes I had it, was phenomenal. This has got to be one of the best arcade monitors in this size range.

Well I found the T"nn" numbers for the other 2 transformers, but I can't see the number for the one that is defective, which is frustrating. It may be right behind it, but it's impossible for me to see back there because it's mounted in my cabinet and I can't get my head back that far. I suppose I could buy a cheap dentist type mirror to stick back there and see if I can find the number.

It looks like I can at least remove and replace it myself because the transformers are attached to the board with thru-type solder pins so all I would need to do is desolder the pins to remove it. The hard part it seems will be to find a replacement part. I imagine there has to be some way to cross reference the part to find a transformer from a different manufacturer with the same specs, since theoretically it should work as long as it has the same input/output voltage. I thought I read online that a transformer's voltage can be identified by using a multimeter which would make it possible to find a replacement, but I've never dabbled into anything this deep with electronics. I have plenty of experience soldering and I'm fairly confident I can discharge the monitor to remove the circuit board so I can remove it and get a closer look at everything, and at least remove the transformer. I'll see if I can find a way to look for that designator number tomorrow since you have a schematic.

Worst case scenario I will have to buy another monitor, which sucks but that's the way it goes sometimes with projects like this. I'm looking into either a Wells Gardner d9800 or Makvision 27/29" tri-sync, but leaning more towards the Makvision because of all the problems and quality issues I keep hearing about with the WG line of monitors. I definitely want to do everything I can to fix this one first though because the money is already spent, and a new monitor won't be cheap, and I REALLY don't want to have to remove it from my cabinet, since it's semi-permanently mounted.

[MonMotha]

Given the size/location and part number, I *think* it's T401 on the blurry schematic.  Middle of the second page.  It lives right on the horizontal yoke output, so it would definitely see some high currents and voltages.  The schematic unfortunately doesn't give any specs on the part

This is a pulse transformer, not a conventional power transformer, so there's more to it than just in/out voltage.

[UberCade]

So in other words my best bet for fixing it would be to either try to fix the transformer myself or find someone who can fix it for me, or be patient and hope eventually I come across a spare board for this particular monitor or someone who is willing to part one out. Sounds like in the mean time I would be best off buying another monitor since there's no way to know how long it would be until I could get the Sanwa fixed. Hopefully this will be my last hurdle in finishing my cabinet.

[MonMotha]

Grab the attention of one of the professional monitor techs that floats around here (Ken Layton, grantspain, qrz, etc.).  Chances are one of them has a pretty good idea as to what to do.  It's not a terribly complicated part.  It just doesn't seem to have a standard part number (so it was likely custom wound for this project).

If you feel like it, the hardest part of re-winding these things is usually getting the darn things apart as they're generally epoxied together.  A hot plate can sometimes be used to heat the assembly until until the epoxy lets go at which point you can separate the two halves of the core and get at the bobbin that the wire is turned on.  You can then yank the wire off (count the turns and note the phasing!) and re-wind it using new enameled wire of similar characteristics.  If you're lucky, the defective winding is the outermost one and will be easy to get to.  You will probably need some kapton tape to put between the two windings to get sufficient isolation.

I've got several of these monitors in storage if you need me to go look at something, but I'd rather not tear one apart

[UberCade]

So, since you have several laying around, you wouldn't want to part with one of the boards would you? 

I'll dig around a little bit in the mean time before I order another monitor and see what I can possibly do about fixing the transformer. There should be some articles online about the process. I'm confident enough in my general mechanical skills and since you say it's not a really complicated part, it won't do any more damage to try to fix it.

[MonMotha]

No, you can't have my boards.  Those monitors of mine are new in box.  As far as I know, they work!

If you do go about trying to re-wind that transformer, make sure you keep things neat and as close to (or exceeding) the original spec as possible.  High currents and voltages are present in that neck of the woods.  That's probably why it broke down in the first place.  They probably didn't get something spec'd quite right.

[Thenasty]

if you live in NJ, you can take that transformer out and have it fix at "Atlantic Kenmark" in Lynhurst. I know the owner. He fixed some motors, transformers etc.. for me. What they will actually do is gut that thing, put new wires in and of course the right winding to it ( I dunno but he does).

The wires inside, I believe are coated (insulated). It looks like bare wire but they are not. Maybe some coating from the wires melted down and now shorting.
But thats just my guest.

Good luck

[MonMotha]

The insulative coating is generally an enamel.  It's pretty thin, but the theory is that it's not near anything at significantly different potential.  This is why kapton tape or similar has to be used between windings that are to be well isolated.  The enamel can sometimes break down due to abrupt temperature change and allow arcing.  Mechanical shock can also cause issues.  Some higher voltage transformers do use thin-wall Teflon insulated wire which is much less susceptible to this, but it makes the transformer a lot bigger and more expensive.

[UberCade]

I'm thinking what I'm going to do is order a new monitor to replace that one for now and remove the transformer and find a professional to fix it.

@Thenasty: I live in California so I couldn't possibly be any further away from NJ (well unless I lived in Japan  ) but you have the right idea. I'll try to find either a shop online or locally who can fix it for me, and if it gets fixed I'll just have an extra backup monitor sitting around in case something else should happen.

I just figure since I don't have any experience with transformers (didn't even know what one looked like until this happened!) I'm better off leaving it to a pro so I don't waste my time and resources. With any luck I'll be able to find somebody who can fix it. Maybe I'll try a few electronics repair shops around here.

I'm looking at getting either a Makvision 27" tri-sync or a Neiman 27" tri-sync. Just waiting for Rick at Neiman to respond to my e-mail. Their shop is closed until Wednesday so I have to wait 'til then (probably at the olympics in Vancouver  ).

[lilshawn]

I live in California so I couldn't possibly be any further away from NJ (well unless I lived in Japan  )

if you lived in Japan, you could run to the corner store and buy a new transformer!!!

 

[StephenH]

You may want to e-mail Rick Nieman at rick@niemandisplays.com.     He may know where to get a replacement part or which part you may need.    Another option would be to note the tube model and see if there is a replacement chassis for it.

[grantspain]

looks like the horizontal drive transformer,most likely one of the windings to the fixing legs is bad/broken and hence arcing-you could probably fix it be making the connection good
i would expect that to be a custom part but if you have any numbers on it then its worth a google

as for replacement chassis I am quite sure rodotron and wei ya will fit on,all you need to do is find out if you have a dual focus or single focus chassis(see how many adjustments are on the flyback)

the sanwa pfx i read recently came out with the same yoke specs as a rodotron 666a/wei ya 3129a

[MonMotha]

The transformer appears to be used to couple the horizontal output pulse back to the micro that generates all the deflection signals for timing closure and also goes somewhere else back earlier in the signal chain.

Where exactly is the thing arcing?  If it's near the pins that solder to the PCB like grantspain described, a fix may be fairly straightforward.  I hadn't thought of that.

The part number does not appear standard.  I got nowhere googling it or anything like it.

IIRC, this is single focus.  Bear in mind that this is a Dynaflat/Pureflat/Trueflat/Whaeveryoulikeotcallitbutitsreallydarnedflat CRT.  A chassis not specifically designed for this may exhibit odd geometry or linearity issues around the edges, especially the left/right sides.