High voltage problem in Midway cabinet (MK2 to NFL Blitz)

GuidoTorpedo

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High voltage problem in Midway cabinet (MK2 to NFL Blitz)

Got this Blitz in that was once an MK2. The 3 amp fuse was blown on the power brick. replaced it, fired it up, monitor shoots fire out of the HV section (Polo, what do you expect).

I remembered reading a thread recently about how all Midway cabs were wired wrong from the factory... something screwy with the 120 line. I put my meter on the 120V, and I'm getting 137V! Yeesh.

Is that what ultimately caused the monitor to fry (other than it is a cheap Italian POS), and how do I fix it?

Thanks,
-Mike
 
the isolation transformer's wired wrong. I don't understand those things very well, I'm just fortunate enough that all the Midway isos I got work correctly.

funny you mention this though, line fuse got blown to smithereens on my Killer Instinct 2 today and it's got a Polo.

no iso in that though, just straight shot AC.

the 137V will definitely fuck shit up though. post pics of the iso. maybe it's on the wrong lugs or something?
 
Hmm. Might need to look into that on mine as well. It's always been a little wonky. I'll try and search for the thread you mentioned.
 
137v coming off the ISO is actually pretty typical.

What was "wired wrong" on those Midway cabs is that they have other things such as the marquee and power supply coming off the same side of the isolation transformer as the monitor.
So even something such as a shorted marquee light ballast has the potential to blow something on the monitor. (blow fuses and components, cause interference, etc, etc)
The monitor isn't separated as it should be.
All of the VIOLET colored lines come from the same "isolated" source.

A lot of these machines seemed to have K7000's in them, which is what I'm used to seeing, so I can't say much for the Polo's and it's affects on them.

You can see in the wiring diagrams that the top diagram "appears" to have the monitor separated....but if you look at the actual transformer diagram below...it's not, everything is tied to the same power source. You can verify this by checking continuity with a meter between all the striped and non-striped violet wires. (power off of course for this check)
 

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I'll have to check this. I get noise in my speakers during screen changes and stuff with attract mode turned off. I also seems to be getting some kind of feedback on the monitor where you can see… it's not really lines, but you can see something shifting back and forth. Hard to explain.
 
I'll have to check this. I get noise in my speakers during screen changes and stuff with attract mode turned off. I also seems to be getting some kind of feedback on the monitor where you can see… it's not really lines, but you can see something shifting back and forth. Hard to explain.

try disconnecting the earth ground (the green wire) that goes to your monitor. happened on an iso setup I dropped into my Tekken Tag... which I inevitably shitcanned and went back to old non-iso brick.

for anyone that gives a shit, my Polo in the KI2 is toast. the chassis fuse glowed orange. even Chad was a bit mystified by that one lol :)

Mr. GuidoTorpedo, I'm inclined to believe your problem lies in the Polo, however, the 137V certainly will not help. I saw a game once that nuked the monitor, power supply, marquee fixture and all from being jumpered to run at 137V soooooooooooooo. however, with the Polo, I would think it would adapt to whatever voltage you toss at it. after all I think they're meant to run at 240V, I guess that's one benefit to it having its own PSU. I know that sounds weird, Polos just suicide themselves for no apparent reason. when they work though they look amazing.
 
try disconnecting the earth ground (the green wire) that goes to your monitor. happened on an iso setup I dropped into my Tekken Tag... which I inevitably shitcanned and went back to old non-iso brick.

for anyone that gives a shit, my Polo in the KI2 is toast. the chassis fuse glowed orange. even Chad was a bit mystified by that one lol :)

Mr. GuidoTorpedo, I'm inclined to believe your problem lies in the Polo, however, the 137V certainly will not help. I saw a game once that nuked the monitor, power supply, marquee fixture and all from being jumpered to run at 137V soooooooooooooo. however, with the Polo, I would think it would adapt to whatever voltage you toss at it. after all I think they're meant to run at 240V, I guess that's one benefit to it having its own PSU. I know that sounds weird, Polos just suicide themselves for no apparent reason. when they work though they look amazing.

The ps is toast too. The bill acceptor that was hooked up sounds dead... Really dead.

You're right about hantarex polos though. When they work, the picture is beautiful.

Mike
 
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