Help! Grey Wire on Power Supply only showing 0.2-0.3 V. Computer constantly restarting in a loop

ud0709

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Feb 2, 2016
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Hello,

My computer is not starting up and in continuously restarting. It does not POST. Starts and turns off in one second, again restarts and turns off in one second. This loop continues. I tried resetting the BIOS which did not work. So I removed the PSU to test it. Its a 200W Dell PSU with a 8-Pin MoBo connector and 4-Pin CPU connector all working on 12V. I did the paper-clip jumpstart, the reading on all wires is perfect (12.13-12.15V) except on the grey wire which shows about 0.2-0.3V. Could someone please help me out with what does it mean and what solution is possible.

Thanks
 
Solution
GRAY , possibly Dell Gray = PS_On
http://www.tomshardware.com/reviews/power-supply-specifications-atx-reference,3061-6.html

The PS_ON signal can be manipulated physically by the computer’s power switch or electronically by the motherboard under software control. PS_ON is an active low signal, meaning the power supply voltage outputs are disabled (the system is off) when the PS_ON is high (greater than or equal to 2.0 V). This excludes the +5 VSB (Standby) on pin nine of the ATX main power connector, which is active whenever the power supply is connected to an AC power source. The power supply maintains the PS_ON signal at either 3.3 V or +5 V. This signal is then routed through the motherboard to the remote switch on the front of...
GRAY , possibly Dell Gray = PS_On
http://www.tomshardware.com/reviews/power-supply-specifications-atx-reference,3061-6.html

The PS_ON signal can be manipulated physically by the computer’s power switch or electronically by the motherboard under software control. PS_ON is an active low signal, meaning the power supply voltage outputs are disabled (the system is off) when the PS_ON is high (greater than or equal to 2.0 V). This excludes the +5 VSB (Standby) on pin nine of the ATX main power connector, which is active whenever the power supply is connected to an AC power source. The power supply maintains the PS_ON signal at either 3.3 V or +5 V. This signal is then routed through the motherboard to the remote switch on the front of the case. When the switch is pressed, the PS_ON signal is grounded. When the power supply sees the PS_ON signal drop to 0.8 V or less, the power supply (and system) is turned on. Thus, the remote switch in a system using an ATX or newer power supply carries up to only +5 V of DC power, rather than the full 120 V–240 V AC current like that of the older AT/LPX form factors.


 
Solution


Thanks for the detailed explanation. Should I replace the PSU or there is any manipulation that I can do?