My computer light turns on then off, no fan no screen
Changed the power supply and Power On switch?
New parts? Okay. We'll come back to them. For now, lets look over some simple things.
I can tell you that even after 20+ years as a tech, I still get a little zealous, when it comes to building computers. Sometimes we get into a rush, and overlook the simple things.
1.Are you sure the 20/24-pin motherboard power cable, is in tight, and down in there?
2.Are you sure the Front Panel connector, is connected right on the motherboard? Some Front Panel's have individual wires with terminal ends, that go on separate pins on the motherboard Front Panel header.
I'm asking are you sure the Power On switch is connected to the right pins, on the motherboard Front Panel header.
Everything good so far? Okay, lets look at the motherboard.
Look at the Electrolytic Capacitors on the motherboard. Specifically the ones that surround the processor. See if they show obvious signs of being bad.
Here is a link that will show you what Electrolytic Capacitors look like, and the visual signs of failure of them,
Good so far? Okay, lets check out that power supply, and at the same time, check out the Power On switch. Even if these items are brand new, they can still be bad.
I need you to make a jumper wire. This is to jump the Soft Power On, part of the power supply.
Wire needs to be like the power supply connector wires. That thick. It needs to have insulation on it. Should be 3 inches long, and have about 3/4th's of an inch of insulation, removed from each end.
Twist the ends tight, and into a pointed shape. Bend the wire into a U shape.
The 20/24-pin motherboard power cable, needs to be plugged into the motherboard. Where the wires go into the connector, there are socket holes. For every wire going down in there, there is a metal terminal end, on the end of each wire. The metal terminal end is pretty far down in there. Your jumper wire must go down in the socket hole, with the wire that is in the socket hole now.
You will see a Green wire, and a bunch of Black wires. The Green wire is the Soft Power On wire.
ANY Black wire is a Ground wire.
You want to jump across the Green wire, to ANY Black wire. (You can use the Black wire that is next to the Green wire. Just wanted you to know that you could use ANY Black wire you see)
Computer plugged into power. You may want to wear a glove on the hand that plugs the jumper wire in. The reason is that there will be a spark.
Not a big one, but I want you to feel safe.
Just stick one end of the jumper wire, down in the Green wire socket hole. Make sure it's deep enough to touch that metal terminal end. Now since the jumper wire is a U shape, just stick the other end in the Black wire socket hole.
You only want to touch it momentarily. Around 1 to 2 seconds. Then remove it.
If the power supply comes on, you have a bad Power On switch, or bad Front Panel header on the motherboard. If the power supply doesn't come on, you have a bad power supply.
With the power supply running, you can see if your motherboard is bad or not. I have seen VERY FEW motherboards, that have a bad Front Panel header. (Header is a -> Connector <- when referring to the motherboard)
Apr 28, 2009 |
Smart Modular SV3170A