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Author Topic: Power supply question related to AC  (Read 1281 times)

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Power supply question related to AC
« on: December 22, 2016, 11:18:43 am »
I just sold my Galaga (with JAMMA internals) and so that my buyer has some longevity I thought I'd be nice and install a brand new power supply (the old one works but keeps needing adjustment of the voltage potentiometer). I've had this Suzo-Happ switching PS sitting around in its box for a good 7 years. I install it, but then took a long time figuring out the AC hookup.

My old PS had two AC terminals (marked AC) and one FG terminal (with nothing attached to it).

The new PS has AC(live), AC(neutral) and FG. So is it logical to assume that it MATTERS that I not mix up the live and the neutral? And what about not having a ground attached?

So then I had to determine which was live and which was neutral. I was not able to properly determine this based on the wiring (it doesn't quite match up that Bob Roberts AC wiring diagram that's on the web) so I took a best-guess. Power-up and the PS is squealing and the red LED doesn't come on until I power OFF. (That's right, it lights up on power OFF and then slowly dims away). The +5 measures 1.8 and shows NO change on adjustment. (And don't worry, I had a spare "just for testing" jamma board attached. Not one I care about.)

So to me the squeal sounds like bad caps, but how is this possible straight out of the box? Yeah it's been sitting there for 7 years but still...the old PS is at least 20 years old.

Any input on testing the AC and whether it matters or not on a Suzo-Happ switcher would be appreciated.



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Re: Power supply question related to AC
« Reply #1 on: December 22, 2016, 12:56:43 pm »
 Cant comment on the PS as I have no clue but.
Depending on your supply requirements in the country you live the easiest way to determine L or N is to test to earth.
You will get voltage between L and Earth, You will get 0V between Neutral and Earth.