Hotwire Power supply

[Shane Thoen]

I'm working on a personal project and I'm using a 250w ATX computer power
supply. Is there any way to cross some wires in the 24-pin connector that
goes to the motherboard to always have the powersupply "on" even when it's
not connected to a MB? Looking at the specs for the PS, the
green lead (pin #16) is the PS_ON/OFF - do I cross that with something?

Or am I completely off my rocker and smoking crack?

Thanks in advance!!

Shane Thoen

 

[John McGaw]

I'm working on a personal project and I'm using a 250w ATX computer power
supply. Is there any way to cross some wires in the 24-pin connector that
goes to the motherboard to always have the powersupply "on" even when it's
not connected to a MB? Looking at the specs for the PS, the
green lead (pin #16) is the PS_ON/OFF - do I cross that with something?

Or am I completely off my rocker and smoking crack?

Thanks in advance!!

Shane Thoen

Are you sure about your pin numbers? The references I checked say that pin
#14 is the ps_on/off. It also says that it is "active low" which jibes with
my recollection that one simply grounds that pin to hotwire the supply.

http://www.hardwarebook.net/connector/power/atxpower.html
http://www.hardwaresecrets.com/faqpowersupply.html

 

[Guest]

Yes, you are correct. Looking closer, the specs I was looking at is for a
different power supply. The specs I was looking at were for a 24-pin and
the one I have to hotwire is a 20-pin. I do thank you for the reference
links! They are certainly going to come in handy!

Unfortunately, when I cross the green PS_ON with a black ground, the PS fan
turns for half a second and then dies. Does it matter what kind of wire I
use? I've tried everything from a basic paperclip to a wire from a defunct
PS. Are there any other wires that need to be crossed or would this seem to
indicate that the PS is faulty?

Thank you kindly!

Shane T

 

[user]

Yes, you are correct. Looking closer, the specs I was looking at is for a
different power supply. The specs I was looking at were for a 24-pin and
the one I have to hotwire is a 20-pin. I do thank you for the reference
links! They are certainly going to come in handy!

Unfortunately, when I cross the green PS_ON with a black ground, the PS fan
turns for half a second and then dies. Does it matter what kind of wire I
use? I've tried everything from a basic paperclip to a wire from a defunct
PS. Are there any other wires that need to be crossed or would this seem to
indicate that the PS is faulty?

Thank you kindly!

Shane T

You might need to load the power supply down. Some supplies shut down
when little or no current is drawn.

 

[Guest]

That did it all right! I stuck two case fans and an old HDD on the leads
and it worked perfectly.

Thanks!!

Shane T

 

[ric]

I'm working on a personal project and I'm using a 250w ATX computer power
supply. Is there any way to cross some wires in the 24-pin connector that
goes to the motherboard to always have the powersupply "on" even when it's
not connected to a MB? Looking at the specs for the PS, the
green lead (pin #16) is the PS_ON/OFF - do I cross that with something?

Connect it to ground (any black wire.)

 

[ric]

Are you sure about your pin numbers? The references I checked say that pin
#14 is the ps_on/off. It also says that it is "active low" which jibes with
my recollection that one simply grounds that pin to hotwire the supply.

Pin 14 is PS_ON with the standard 20 pin connector. The OP had a
24 pin connector.

http://www.formfactors.org/developer/specs/BTX_Specification v1.0a.pdf

Page 27, Figure 13.

 

[John McGaw]

Pin 14 is PS_ON with the standard 20 pin connector. The OP had a
24 pin connector.

http://www.formfactors.org/developer/specs/BTX_Specification v1.0a.pdf

Page 27, Figure 13.

No, he had a 20 but was looking at the wrong chart. To quote his reply "The
specs I was looking at were for a 24-pin and
the one I have to hotwire is a 20-pin." The only 24-pin ATXs that I have
seen are 450W+ server supplies so I just made a wild stab at it. Even I get
lucky sometimes...

 

[ric]

No, he had a 20 but was looking at the wrong chart. To quote his reply "The
specs I was looking at were for a 24-pin and
the one I have to hotwire is a 20-pin."

Yeah, but that was in his follow-up post. My response was to his
original post where he says, "Is there any way to cross some wires
in the 24-pin connector..."