Is there an easy way to use a computer power supply with out a motherboard? I am assuming that the power supply is checking for an open circuit and not turing on. Let me know if any of you all have any suggestions.
There's usually a loopback connection that requires a jumper. *Many* SMPSs don't like no-load.
...Jim Thompson
-- | James E.Thompson, P.E. | mens | | Analog Innovations, Inc. | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | Phoenix, Arizona Voice:(480)460-2350 | | | E-mail Address at Website Fax:(480)460-2142 | Brass Rat | |
Yes,assuming it's an ATX supply there is a pin (PS-ON) that needs to be taken low to switch the PSU on.
Pinout:
Also remember that some of the rails may have minimum load requirements.
sPoNiX
-Is there an easy way to use a computer power supply with out a
-motherboard? I am assuming that the power supply is checking for an
-open circuit and not turing on. Let me know if any of you all have any
-suggestions.
Read this:
ATX power supplies have an electronic switch that you must hook up. Also for proper regulation you need to provide a load to the 5V (and possible 3.3V on an ATX supply too).
This connector diagram should give you the information you need:
I still use old AT supplies with no problem.
BAJ
I have lots of small ones, like the ones used in external SCSI CD and HD boxes, if any one needs one, two, three... let me know. 115v AC in +-12 and +5 out at 1-2 amps.
Bob
Mike wrote:
On 10 Oct 2003 08:04:44 -0700, snipped-for-privacy@hotmail.com (Mike) Gave us:
Most PC Supplies will shut off if a sudden load transient occurs.
As long as you don't exceed the current flow of the supply you are using or try to drive an inductive load it should work fine....I believe the grey wire needs to be clamped to ground, but you should do a google check to verify.....Good luck on your project....Ross
Newer computer power supplies (after 1995) use what is called a "switching" power supply. They require about a 10% load to operate properly. If they do not have the load then an internal switch will turn them off after about 1 or 2 seconds. You can purchase specuial load resistor plugs that will allow them to kick in.
Switching power supplies don't work as described. Some switching supplies require a minimum load - usually less than
10%. Some will work just fine without any load. To know with certainty: consult the manufacturer's data sheet which is typically found only with minimally acceptable supplies.Furthermore, just because one supply starts without a load does not mean it will do so every time. That test is only experimental evidence. Without also theoretical fact - the specifications - then one can never know with certainty that a power supply can or cannot start without load. Both theory and experiment are always required to know a fact. But we do know this. Not all switching power supplies require a minimum load to startup every time.
Switching power supplies are not new. They existed over 30 years ago - and were quite common in computers long before PC existed.
In the meantime, this URL demonstrates how to test a switching power supply without computer attached. ATX computer power supplies are better tested inside the computer, AND, at minimum, a 3.5 digit multimeter is required. Valid testing without at least that meter is futile
- if not a major time waster:
Further information: alt.sys.pc-clone.gateway2000 "How do you test a power supply?" 11 Oct 2003 alt.comp.hardware.pc-homebuilt "Do you think my PSU is powerful enough?" 13 Oct 2003 "200W power supply good enough?" 6 Oct 2003 alt.comp.periphs.mainboard.asus "will a cheap PSU (antec) kill P4S800?" 15 Oct 2003
"Jan Z." wrote:
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