what is the range for the 12VDC ??

bsdpinball

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I have two power supplies here and when I adjust the 5 volts to get it at about 5.1 the 12V is still in the lower 13's. Is this OK ?
 
I have two power supplies here and when I adjust the 5 volts to get it at about 5.1 the 12V is still in the lower 13's. Is this OK ?

Need more info...
What kind of 12V supply is it?
Regulated or unregulated?
Is it just the 12V into the 5V regulator?
 
12 volts is unregulated. it's not uncommon for you to have like 5.05-5.15V and have the 12V in the 13s. if you ever looked at the specs on power supplies, it'll list what the voltage tolerance will be.

at any rate, I've operated my MKs like this and it never cooked amplifiers or anything like that. they just need at least 12 volts to operate is all.

likewise, the -5 will dip a little below -5V.... well I guess technically it won't dip enough since it's negative, but yeah, I've seen those generally around like -4.85. also very negligible difference.

the +5 is all that really matters, cause if that's too low, your ICs won't have enough juice to function, and if it's too high, you can burn chips out. as long as the +12 isn't north of 14V then you're fine, cause that might be pushing it a bit. make audio components run too hot.
 
tolerance for power supplies has always been in the +/- 10% on every line, anything beyond that is bad and will cause issues. 13.2 is about as high as i'd like to see a psu output.

atleast that's how i always gauge'd it.
 
tolerance for power supplies has always been in the +/- 10% on every line, anything beyond that is bad and will cause issues. 13.2 is about as high as i'd like to see a psu output.

atleast that's how i always gauge'd it.

correct, the very first PSU swap I ever did was on what's now my restored dedicated KI1 :) the old Peter Chou unit that it came with would go into overcurrent protection a lot, and the Happ Power Pro I dropped in, that was my first foray into voltages and such. my MK2 that was in it at the time was very problematic and I assumed it was a voltage thing (which I later discovered 2 years later to be a CRUD on the rom legs thing) and thought it was interesting how I had it at 5.2 and the +12 was like 13.2 lol

yeah, 13.2 is about right though.
 
i learned all about tolerances with my first OCZ PC Psu. it had adjustable 12v rails, a great feature.

btw mecha what do you prefer for a PSU model/brand for your 90's midway fighters/sports games?
 
i learned all about tolerances with my first OCZ PC Psu. it had adjustable 12v rails, a great feature.

btw mecha what do you prefer for a PSU model/brand for your 90's midway fighters/sports games?

Happ Power Pro. my KI and MK2 cabs use screw terminal power supplies, so I used those there. still running the original box type Peter Chou ones in my old MK/Tekken and KI2 cabs... I think I told you about my light bulb thing, after extensive pot wiping I made em work properly again lol.

the Happ Power Pro box types have this stupid bracket on them that doesn't fit inside the Midway AC block, I wound up busting that off for a Blitz 2000. then I swapped my Blitz cabs around, the Sportstation went into the nicer '99 cab that had the original shitbox PSU, and when that went nuts and skyrocketed to 5.40 on its own, I had nothing else and had to use one of those gigantic XT type power supplies in there... kind that you find in a Namco racing game.

all in all, Happ makes the Power Pro in various form factors, just stick with whatever type yours came with originally.
 
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