using a computer power supply without a motherboard

[Mike]

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.

 

[Jim Thompson]

On 10 Oct 2003 08:04:44 -0700, mjhnational@hotmail.com (Mike) wrote:

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 Voice480)460-2350 | |
| E-mail Address at Website Fax480)460-2142 | Brass Rat |
| http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[S P O N I X]

On 10 Oct 2003 08:04:44 -0700, mjhnational@hotmail.com (Mike) wrote:

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.

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: http://xtronics.com/reference/atx_pinout.htm

Also remember that some of the rails may have minimum load
requirements.

sPoNiX

 

[Byron A Jeff]

In article <27d5f974.0310100704.3a4a3b36@posting.google.com>,
Mike <mjhnational@hotmail.com> wrote:
-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: http://web2.murraystate.edu/andy.batts/ps/PowerSupply.htm

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:

http://hardwarebook.net/connector/power/atxpower.html

I still use old AT supplies with no problem.

BAJ

 

[Bob Huish]

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:

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.

 

[DarkMatter]

On 10 Oct 2003 08:04:44 -0700, mjhnational@hotmail.com (Mike) Gave us:

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.

Most PC Supplies will shut off if a sudden load transient occurs.

 

[Ross Mac]

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

"Mike" <mjhnational@hotmail.com> wrote in message
news:27d5f974.0310100704.3a4a3b36@posting.google.com...

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.

 

[Jan Z.]

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.

--
JZ
Anchorage, Alaska
"Mike" <mjhnational@hotmail.com> wrote in message
news:27d5f974.0310100704.3a4a3b36@posting.google.com...

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.

 

[w_tom]

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:
http://www.hardwaresite.net/faqpowersupply.html

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:

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.