Killer Instinct Cabinet- hum from speakers

Battlesmurf

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So I've been fighting this for awhile. The speakers are not the issue. The board is not the issue. I've disconnected the florescent tube as well as the monitor/iso transformer. The power supply has been swapped out. This leaves the wiring in the cabinet or something else I've missed.

I tried a little ground loop isolator- and it works- *but* the volume is insanely low (100% with gli is equal to about 10% without).

What am I missing? The hum is very distracting- if I can eliminate it without using the GLI that'd be great. If I do have to use the GLI- can I run some kind of amp to bump up the volume?


Thanks fellas!
 
the early DCS hardware did that. there's no way around it.

if you're getting a very obnoxious buzz then I would check that -5V is present.
 
I can re check the grounds- is there a list somewhere of exactly which ones are on these?

Lets say I go with the GLI- can I amp the signal before or after it?

Lowlevel- what all have you tried?
 
I can re check the grounds- is there a list somewhere of exactly which ones are on these?

Lets say I go with the GLI- can I amp the signal before or after it?

Lowlevel- what all have you tried?


I've never not had it be a ground loop issue. Plus 1 for checking grounds but that aside Putting in an isolator has fixed it every time for me.
I've also not had the volume be an issue when putting one in -- ie it didn't affect the volume. If the volume is low or can;t be adjusted then I'd say you have other issues.
If you have to put an amp in you'd need to do it before the isolator otherwise you will possibly run into the same problem because of the ground loop issue.
 
I've never not had it be a ground loop issue. Plus 1 for checking grounds but that aside Putting in an isolator has fixed it every time for me.
I've also not had the volume be an issue when putting one in -- ie it didn't affect the volume. If the volume is low or can;t be adjusted then I'd say you have other issues.
If you have to put an amp in you'd need to do it before the isolator otherwise you will possibly run into the same problem because of the ground loop issue.

I wonder if it has to do with the type of isolator. Mind if I ask how you're hooking it up and what kind you're using?
 
I wonder if it has to do with the type of isolator. Mind if I ask how you're hooking it up and what kind you're using?

I've always just used the cheap radio shack ones - if you search for "audio ground loop isolator" you usually get a few options. Depending on your specific situation you may want to decide between RCA plugs vs the 3.5 mm jack plugs.

you have to break the speaker line between the source and the speakers with the isolator. I think on that killer instinct board there is a 3.5mm audio out jack?? that's where I'd put it in.
 
I've always just used the cheap radio shack ones - if you search for "audio ground loop isolator" you usually get a few options. Depending on your specific situation you may want to decide between RCA plugs vs the 3.5 mm jack plugs.

you have to break the speaker line between the source and the speakers with the isolator. I think on that killer instinct board there is a 3.5mm audio out jack?? that's where I'd put it in.

No 3.5mm jack that I've seen.

The isolators have stereo 3.5mm jacks, whereas the KI cabinet is just - +/mono. How do you usually go about wiring these guys up? I know that the 3.5mm stereo plugs are L/R/Ground.
 
No 3.5mm jack that I've seen.



The isolators have stereo 3.5mm jacks, whereas the KI cabinet is just - +/mono. How do you usually go about wiring these guys up? I know that the 3.5mm stereo plugs are L/R/Ground.



RCA jacks then. You just have to wire ones in and then plugs those into the GLI.
 
I'm serious. every single one of you in this thread are vastly overcomplicating this. Midway produced multiple games with this sound hardware, I've worked on every single one of them, I've never had to resort to audio isolators. the grounds won't even make a difference. if your power supply is putting out -5V off from what it should be it will hum louder than usual.

even when it all works it has a noticeable buzz when there's no sound playing.
 
I'm serious. every single one of you in this thread are vastly overcomplicating this. Midway produced multiple games with this sound hardware, I've worked on every single one of them, I've never had to resort to audio isolators. the grounds won't even make a difference. if your power supply is putting out -5V off from what it should be it will hum louder than usual.

even when it all works it has a noticeable buzz when there's no sound playing.

100% agree --- however the OP said he swapped it out already with a myriad of other "fixes" he's tried - to no avail --

just trying to offer him some suggestions on something that has been successful for me when all else failed - which is what he was asking for -

but yes indeed the power supply can cause all sorts of issues...
 
I have rules when it comes to games. if you intend on keeping it, you can cap the monitor. and if you intend on keeping it, you replace the power supply.

in my adventures of building an arcade with north of 100 games from various sources, I've found that every single game had a Meanwell, Wei-Ya, Min Dong, or some other equivalent piece of shit power supply. they all got new Power Pros and that's just the end of it.

I used to think it was a total myth that these Midway games were picky about power, but I'm starting to realize the opposite. try disconnecting the -5V from an MK2 or KI or other equivalent DCS game -- if your problem sounds like a lesser form of that, replace the power supply.

I had a cabinet at work that for all intents and purposes worked fine. then the picture developed snow. guess what fixed that? a new power supply. I had a WrestleMania there that would throw random rom errors or black out during gameplay. guess what fixed that? a new power supply.

people think this is a joke but it isn't. the power supply is one of the most important parts in the game. I didn't make a guide about power supplies for my health; I made it because the reality is most people don't respect the fact that you can completely ruin your hardware not knowing how it works or you can make your game not work because you have no business turning knobs without a rhyme or reason for why those adjustments exist in the first place.
 
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