Donkey Kong & Switching Power supply - Sprites - Why?

barakawins

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Donkey Kong & Switching Power supply - Sprites - Why?

Hooked up an arcadeshop Happ Suzo power supply with the nintendo adapter in my Donkey Kong. It plays o.k. But, I get sprites from time to time. I checked the voltage at the rams and they are 5.1vdc. I put the original supply back in and it works fine. Anyone experience this? I tired in the 115vac to the proper lugs at the bottom of the cabinet to the small power strip by the transformer. Hopefully someone knows how to resolve this. I did the same set up for DK Junior and I get sprites too.

Is there a cap kit for Nintendo Power supplies?
 
For some reason, some DK PCB's just don't like switchers. Not sure if there's anything you can do about it.
 
It's the -5VDC line. Most standard switchers are rated at 1 amp (some, not even that much) on the -5VDC line. Donkey Kong motherboards are stuffed with quite a few ECL chips. These chips operate on the -5VDC rail. The switchers are't beefy enough to meet the demands of the motherboard.

Edward
 
If you use the original supply and it works fine, then why are you trying to wire in a switcher? :D

If you're worried about caps in the power supply, I don't know if anyone sells a cap kit per say, but you can just order the caps individually from Mouser or any other component distributor.

-Ian
 
It's the -5VDC line. Most standard switchers are rated at 1 amp (some, not even that much) on the -5VDC line. Donkey Kong motherboards are stuffed with quite a few ECL chips. These chips operate on the -5VDC rail. The switchers are't beefy enough to meet the demands of the motherboard.

Edward
To add to that BITD when I was messing with DK boards I measured that a
typical DK board will draw 1A or more on the -5VDC line. Most switchers do not
actually "switch" the -5v, its usually just a simple 7905 circuit and the amount
of current you can draw out of it is usually dependent on that design and/or what
type of heat sinking they put on the 7905. So some switchers might be able to
handle the load, others not. The graphics on DK type boards are highly susceptible
to lack of -5v and also to heat.
 
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