Need help identifying/fixing this Mortal Kombat II monitor

[Tahnok]

I just got a Mortal Kombat II cabinet (converted to Police Trainer) and the monitor doesn't work at all. The guy I bought it from says that the entire game used to work, but then the monitor just didn't come on one day. Now, when the cabinet is turned on, it has sound and takes input, but no picture. The screen remains completely blank.

I have tried to figure out what this monitor is, but I still have no idea. I can't find any information on this it (other than the fact that other people with MKIIs were having problems identifying it too). A picture of the label on the tube is below.

The monitor doesn't seem to be doing anything at all. No crack like the flyback is powering up or crackles when it turns off. No glow at all, on the display or the neck.

I have checked and made sure that the voltage going into the monitor chassis is what it says it should be. I have also checked and made sure that the board is outputting a signal (though, I haven't checked v-sync and h-sync, since the LCD I was checking with wouldn't allow it).

The problem in this thread seems an awful lot like what is going on with mine. Since I didn't own the cab when the monitor died though, I can't say whether it was cold when it died, or if the image changed size or color. The monitor pictured looks quite a bit like mine, except that the neckboards are ever so slightly different.

I haven't pulled anything out yet, since I really hate working with monitors (they're big, heavy, and can have high voltage sitting on them). If a better picture is really needed though, I'll pull it out.

As always, thanks for the help!

[Ken Layton]

It's some kind of a Hantarex brand monitor.

[Tahnok]

I think you're right. Looking on Bob's site, it appears to be the Hantarex Polo. I must have missed that one in my original search (not knowing what brand I was looking for).

I just pulled off the monitor glass and felt around for a static charge. Absolutely nothing. It seems like everything so far is pointing to the flyback transformer, right? I guess I will pull out the entire assembly and take a look at it. Let's hope it's something simple, like a disconnected wire.

[grantspain]

its a hanterax mtc 9000,the most common faults on these were dry joints on the flyback,they have a bu508a as the h.o.t these blew alot,also problems with the flyback

[Tahnok]

its a hanterax mtc 9000,the most common faults on these were dry joints on the flyback,they have a bu508a as the h.o.t these blew alot,also problems with the flyback

Oh, OK, thanks. That could have been bad if I had ordered parts for a different model.

That would be great if it's just a bad joint. Is that really the kind of thing that can just happen over night though?

[grantspain]

BIG SORRY DUDE,i did not get the first photo-ITS A HANTAREX POLO 1,sorry for the confusion,same faults apply though but the h.o.t will be different

[Ken Layton]

Check it definitely for bad solder joints, but I think you should also install a capkit.

[Tahnok]

Alright, thanks again for the clarification. I was just about to discharge it and pull the board out. I'll try to take a look at it tonight and see if there is anything obvious.

I will probably order a cap kit, and possibly a flyback. I just found out that the cabinet was built late '93. I doubt the previous owners have done anything to the monitor since then. Right now though, I want to make sure it works before I invest time and money recapping it.

[Ken Layton]

Hantarex monitors typically have so many bad capacitors that the monitor won't power up.Ten bucks for a capkit is a good investment.

[grantspain]

i'm glad i got my ammended message to you in time,once again sorry for the confusion-the chassis you have is one of the very first polo's,usually a polo will have a metal cage around the power supply of the monitor which yours does not have,hence my mistake.anyway a chassis of that age will certainly need new caps,is there any sound like a faint ticking coming from your chassis?,i can give you more info on tuesday on the most common faults on these when i'm back at work

[Tahnok]

No ticking, no sound at all. No lights either. It doesn't appear to have any life in it at all.

I got around to pulling out the boards tonight and taking a look at them (discharge didn't make even the faintest crack). One of the first things I noticed is that this board has had a lot of work done on it (contrary to what I thought before); the tell-tale flux is everywhere. I also found a joint right under the flyback that looked promising. The pad had solder on it, but the lead had completely come loose and was floating in the center. I fixed it (and touched a few that looked iffy), hooked it up, and got nothing again. It didn't seem to change anything at all. So there goes the easy fix idea.

Something I find strange about this whole thing is that not even the filament lights. I would have thought that even if the flyback is dead that the neck would still glow. This suggests to me that the entire thing is loosing power somewhere (or the entire tube is dead). Any thoughts?

Could it really be possible that the caps are so dry they are actually preventing things from even partially working? If it is the caps, then why would it die so suddenly? I don't doubt your expertise (and I will be ordering a cap kit soon), I'm just trying to understand how this could be possible.

[Ken Layton]

In most monitors regardless of brand, the filament in the tube is lit by a winding inside the flyback. The flyback works from the horizontal deflection circuit. So if a bad capacitor or two (or even more!) were present then this circuit would not operate and no drive to the flyback would occur. No power to flyback = no power to other parts of the monitor.

[Tahnok]

Ah, OK, thanks for the explanation. I was under the impression that lower voltage parts of the circuit were being powered by a separate circuit. I'll order a cap kit in a bit, but I won't be able to install it for a couple weeks. I'll be sure to dig this thread back up and let you know how it goes.

[grantspain]

you gotta watch out for broken tracks especially around the two load resistor on the right hand side of the chassis,also there is a diode that blows-tomorrow i will send you all my polo repair advice(alot i have forgotten but i have it written down),but the usual culprits are caps,h.o.t,lopti,track damage,dry joint.oh and that bloody diode(thats caught me out a few times)