Power supply

[crocodile13]

My main pc is refusing to power up, when switched on there is responce at all.
Ive changed the power supply with a spare one I had and it's still the same .
I think it may be the switch on the case itself but im not sure ive tested the switch with an ohmeter and it seems to be ok or it may be the mobo itself . Im reluctant to buy a new case if it is the mobo, is there anyway i can test the mobo using a meter or can u think of any othert methods to isolate the problem

[kracken]

ATX Power Supply

(at the motherboard)
(at the cable)

20 PIN MOLEX 39-29-9202 at the motherboard
20 PIN MOLEX 39-01-2200 at the cable

<TABLE border=1><TBODY><TR><TH>Pin</TH><TH>Name</TH><TH width=16> </TH><TH>Color</TH><TH>Description</TH></TR><TR><TD>1</TD><TD>3.3V</TD><TD align=middle width=16 bgColor=#ff7f00> </TD><TD>Orange</TD><TD>+3.3 VDC</TD></TR><TR><TD>2</TD><TD>3.3V</TD><TD align=middle width=16 bgColor=#ff7f00> </TD><TD>Orange</TD><TD>+3.3 VDC</TD></TR><TR><TD>3</TD><TD>COM</TD><TD align=middle width=16 bgColor=#000000> </TD><TD>Black</TD><TD>Ground</TD></TR><TR><TD>4</TD><TD>5V</TD><TD align=middle width=16 bgColor=#ff0000> </TD><TD>Red</TD><TD>+5 VDC</TD></TR><TR><TD>5</TD><TD>COM</TD><TD align=middle width=16 bgColor=#000000> </TD><TD>Black</TD><TD>Ground</TD></TR><TR><TD>6</TD><TD>5V</TD><TD align=middle width=16 bgColor=#ff0000> </TD><TD>Red</TD><TD>+5 VDC</TD></TR><TR><TD>7</TD><TD>COM</TD><TD align=middle width=16 bgColor=#000000> </TD><TD>Black</TD><TD>Ground</TD></TR><TR><TD>8</TD><TD>PWR_OK</TD><TD align=middle width=16 bgColor=#777777> </TD><TD>Gray</TD><TD>Power Ok (+5V & +3.3V is ok)</TD></TR><TR><TD>9</TD><TD>5VSB</TD><TD align=middle width=16 bgColor=#800080> </TD><TD>Purple</TD><TD>+5 VDC Standby Voltage (max 10mA)</TD></TR><TR><TD>10</TD><TD>12V</TD><TD align=middle width=16 bgColor=#ffff00> </TD><TD>Yellow</TD><TD>+12 VDC</TD></TR><TR><TD>11</TD><TD>3.3V</TD><TD align=middle width=16 bgColor=#ff7f00> </TD><TD>Orange</TD><TD>+3.3 VDC</TD></TR><TR><TD>12</TD><TD>-12V</TD><TD align=middle width=16 bgColor=#0000ff> </TD><TD>Blue</TD><TD>-12 VDC</TD></TR><TR><TD>13</TD><TD>COM</TD><TD align=middle width=16 bgColor=#000000> </TD><TD>Black</TD><TD>Ground</TD></TR><TR><TD>14</TD><TD>/PS_ON</TD><TD align=middle width=16 bgColor=#00ff00> </TD><TD>Green</TD><TD>Power Supply On (active low)</TD></TR><TR><TD>15</TD><TD>COM</TD><TD align=middle width=16 bgColor=#000000> </TD><TD>Black</TD><TD>Ground</TD></TR><TR><TD>16</TD><TD>COM</TD><TD align=middle width=16 bgColor=#000000> </TD><TD>Black</TD><TD>Ground</TD></TR><TR><TD>17</TD><TD>COM</TD><TD align=middle width=16 bgColor=#000000> </TD><TD>Black</TD><TD>Ground</TD></TR><TR><TD>18</TD><TD>-5V</TD><TD align=middle width=16 bgColor=#ffffff> </TD><TD>White</TD><TD>-5 VDC</TD></TR><TR><TD>19</TD><TD>5V</TD><TD align=middle width=16 bgColor=#ff0000> </TD><TD>Red</TD><TD>+5 VDC</TD></TR><TR><TD>20</TD><TD>5V</TD><TD align=middle width=16 bgColor=#ff0000> </TD><TD>Red</TD><TD>+5 VDC</TD></TR></TBODY></TABLE>

Recheck the outputs with a multimeter/voltmeter of the connector , but as you say u allready tried another PSU and you dont think its that. I suspect its the power on/off switch

[Leeum]

Check the power button connection between the case and the motherboard.

[flexylexy]

check ur main fuse lol.
could it be ur battery??
reset the cmos..

[Packers]

how about the power cord?

[Q-Buster]

First thing I would do is check the mains lead to the PC, if your monitor is normally powered from the PC power supply output, then connect the two leads together, you should have power at the monitor, even though obviously you will have no picture. If that works, reconnect the mains to the PC and check that you can start the power supply by removing the plug from the motherboard and with a paperclip or short piece of wire, short the GREEN wire (pin 14) to a ground connection (say pin 16). If the PSU is OK and the mains lead is OK, then the PSU should start up. If it passes this test, then reconnect the lead to the motherboard. Next try shorting momentarily, with a fine screwdriver, the pins that the case switch go to. (Check with the motherboard manual that you have the correct pins.) Once again, the power supply should start. If it doesn't start at this point, I would strongly suspect the motherboard; if it does, it is the case switch/wiring thats causing your problems.

Q-Buster

[crocodile13]

Thanks for all ur help guys turned out both power supplies were goosed , I tried a 3rd power supply and it worked a treat

Thanks again for all ur suggestions