There are at least two reason that I want to understand this.
I saw an 'empty' case with power-supply that was rigged up
with some spooky lights inside a case that has a plexiglass
side panel, so you can see (red, blue, green) lights illuminate
the inside of this case.
What, exactly, are these lights, or at least, what is the technology
behind them, for example: LED, Cold-Cathode, Neon, plain old bulb
So, I purchased the empty case, an ATX power-supply, and
a couple of these lights, and an instruction sheet, but quickly
realized after I brought it home that I was sorely lacking in
conceptual knowledge as to the theory behind the wiring.
(The display model in the store is plugged in and the lights
come on when the power-supply is turned on. But, there is
no mother-board in the display model at all.)
Are you 100% sure there was only that much to the case/system? Often
a display model of something can have additional misc. parts to make
it do it's "thing". In this case there might've been a rigged
connector plugged into the power supply, that shorted the PS_ON line
to ground and perhaps a load on the 5V rail, dpending on what rail,
how much power the lights use. This wouldn't be needed in a system
with motherboard/etc, only to correctly wire up the lights.
So, based on what you posters have said, I now know that
some jumpering of wires is probably being done. (Actually,
I do NOT recall now whether the FANS were on.)
These lights probably need only 5-volts to drive them?
Perhaps I'm assuming you want this to be a whole system but you did
only want a case with no motherboard?
I don't know about 5V, there's not much that uses 5V BUT an LED-type
could use either 5V or 12V, depending on the size of the included
resistor, and the lighting design... if in doubt always try the lower
voltage before the higher one.
Another reason I wanted to know was that I had a machine go
dead (would NOT power up) last week, and since I had no
clue at all how to trouble-shoot that problem, I had to shell
out money to a fixit place just to learn whether I had a power-supply/
power-switch problem or a mother-board failure.
If they couldn't narrow it down more than that, you were taken for
money with no proper diagnosis... it's very easy to determine if it's
the motherboard or the switch, just remove the switch plug and jumper
or short the pins with something metal. However, only the most
severly damaged motherboard won't turn on a properly working power
supply, or of course if the board or wiring is shorted.
(They first diagnosed it as the front panel swtich, replaced that,
I took it home, it STILL would not power up, took it back, and
they now tell me I have a bad motherboard. I'm starting to understand
now why it took them 1.5 hours of labor and two tries just to
get to this point.)
In less than 1/2 hour they should've been able to swap in a different
PSU and switch for testing, have a definitive diagnosis. You were
taken by an incompetent shop. IMHO, they shouldn't have gotten a
penny if they can't even diagnose something this simple, but maybe
they didn't even have a single decent (spare) power supply to try,
only junk. Many shops do use junk PSU unless something else is
special-ordered.
Hope this satisfies the curiosity about why I wanted to understand
this stuff better.
Cheers...
Half the time a shop diagnoses a bad board, it's a junk power supply.
The rest of the time it could be a number of things, the board or a
BIOS setting or dead video card or hard drive or...
The good old swap-in-better-power-supply test is the easiest way, but
certainly NOT the same make/model, if it's junk.
If the power supply is a generic I'd go ahead and replace it anyway,
even if it turns out to be the motherboard. Also I already mentioned
how to test the switch, just unplug it and short the appropriate two
pins, are in the motherboard manual or silk-screened on the board
itself right under the appropriate pins.
Dave
