Maximum Force Cabinet Works But No Video

[EvilBean42]

Hey All,
I started my journey on the following thread but it was suggested that I start over.
http://forum.arcadecontrols.com/index.php/topic,147500.msg1536001.html#msg1536001

I am a facilities tech and my company owns a few cabinets, one of them is a Maximum Force and doesn't currently work. Here is what I know, any advice is appreciated and I'm happy to do some further digging if you guys need me to check something.

Game used to work fully during the time we had it. We recently moved it to a new warehouse. A problem occurred at some point during the move, or shortly after.

Game operates, but the screen doesn't come on.

There is no neck glow at the back of the monitor.

The neck board does not appear to be getting power at all.

The deflection board has power coming in, and power going out to the display. Fuse is ok when checked for continuity, but power doesn't seem to be going through it.

All connections seem ok, there are no signs of any components frying.

The main board has either low voltage, or high voltage error LEDs lit. I've tried to adjust the power supply but there is no gap between too high and too low. I've gotten it to the point where one is out and the other will just sparkle dimly, but I can't get them to turn off completely.

Could it just be the power supply or do I likely have a chassis issue as well? What is the likelihood of the monitor itself being bad? My company is fine with me spending some $ to get it back up and running, but I don't want to order parts and replace them only to find out that something else is bad and it's a total loss.

Thanks for any assistance I get, and also thanks for the assistance I've already gotten from this forum. You can be sure I had no idea what a neck board was yesterday.
I'm including lots of pictures of the game, which does appear to be an original, authentic cabinet as opposed to a convert. If there are more specific or detailed pictures that would be helpful let me know.

[EvilBean42]

A friend of a friend recommended replacing the High Output Transistor. He said it would be a 3 pin transistor mounted on the heat sink. I see a few transistors on the neck board that meet that description. Should I just try to swap all of them? Does this sound like something worth trying in the first place? Is there anything else I should change while I'm in there? Does anybody have suggestions for where I can find a replacement? Again, any guidance is greatly appreciated.

[lilshawn]

honestly by the looks of the things i'm reading, it might be best to try and find a repair company that can take this on for you. The CRT monitor can harbor some really nasty voltages in the "kill you very much dead and it will hurt the whole time because you'll be frozen in place unable to do anything about it" kind of range.

that said, if you feel you are competent enough electronically and electrically to mess with this, the mentioned transistor is a "horizontal output transistor" or HOT. it will be mounted on the bigger board called the deflection board (the smaller board colloquially known as the "neck board") it will be the big black nasty high voltage transformer with the wire going to the tube body. this tube can hold in excess of 20,000 volts, so it must be discharged accordingly before removal and/or repair. do a search on youtube for "CRT discharge" and you'll see lots of guides on how to do it.

you'll not want to just jump on the monitor being the issue. you could have a power issue causing no image... a signal issue causing no image... a signal grounding issue causing no image...

it does sound like you might have a power issue, as you mentioned that there was continuity through the fuse...but it didn't appear the game was booting....

check the 2 power wires and make sure you are getting 120v (or 220v or whatever your local power grid supplies) start at the wall and work your way into the cabinet. be sure the power supply for the game has power... then check the outputs of the power supply. 5v....12v.....3.3v some of them are adjustable... it's a regular style computer power supply with an ATX connector. if it seems off, you can replace it with any computer power supply with an ATX connector and the appropriate molex connectors for your hard drive.

hook a vga monitor to the output of the videocard (you may have to change some switch settings to get a compatible signal for it like 640x480) but get the game working FIRST... then worry about the monitor from there.

[EvilBean42]

Thanks!! I appreciate the advice. The game DOES work, I can hear it running in the background. There just isn't any image. While I don't know if I can successfully get it up and running, I feel confident in my ability to attempt a repair without frying myself. I don't have experience with arcade cabinets but I have had plenty of electronics repair experience on other items (LED TVs, commercial kitchen appliances, automobiles, PLC conveyance, etc) throughout my career. I will be sure to follow the discharge procedures, wear PPE, and (just in case something goes spectacularly wrong) videotape it.

[lilshawn]

a good rule for newbies to follow is always keep one hand in your pocket when you are probing around. keeps your heart from getting zapped if you do touch something you shouldn't.

but yeah, if you are playing "blind" and the game sounds like it's working then make sure you are getting 120v to the monitor... if the power is good going in... find the biggest fattest capacitor next to where the power goes in... this is your main B+ filter capacitor. it should have a bit more than live voltage (~116 to 160v DC in it... it's also okay if it's going up and down a bit as the monitor loads and unloads the power supply... as long as it has at least 110vdc ) if it's way lower there is a definite problem with the input (bridge rectifier or the like).

otherwise we keep going down the line. find out where the voltage stops.