Built PC not turning on completely

[kaschenberg]

Hello, been a long time reader here but never posted.
I've got a pc that I've built a couple years ago consisting of:

Raidmax 450w psu
MSI k9a2 platinum mobo
AMD Athlon x2
2gb ddr2 800mhz ram
ati 5770 1gb

Last night I was just browsing the web and my screen went black. Holding the power button on the case did nothing, totally unresponsive even though it was still running.

I flipped the psu switch, then back on. I pushed the power button - it turns on and seems normal but no beeps and nothing is displayed on my screen.

Where should I start first?

Thanks for the input guys, I appreciate it.

 

[rolli59]

http://www.tomshardware.com/forum/261145-31-perform-steps-posting-boot-video-problems
Check out the bread boarding linked to in the guide, my first suspicion would go towards the PSU though.

 

[kaschenberg]

Yeah same here. I was wondering though, can the PSU be bad even though it turns the motherboard/components on but still not be supplying the correct power? I've seen Dell's that will turn on but the power button blinks orange when the PSU is dead.

 

[ujaansona]

Troubleshooting tips from Toms:
http://www.tomshardware.com/forum/261145-31-perform-steps-posting-boot-video-problems

I want to highlight:
6. Have you tried booting with just one stick of RAM installed? (Try each stick of RAM individually in each RAM slot.) If you can get the system to boot with a single stick of RAM, you should manually set the RAM speed, timings, and voltage to the manufacturers specs in the BIOS before attempting to boot with all sticks of RAM installed. On a personal note: Clean the RAM contacts(exposed pins on RAM) with spirit.

"The best way to check the PSU is to swap it with a known good PSU of similar capacity. Brand new, out of the box, untested does not count as a known good PSU. PSU's, like all components, can be DOA.

Next best thing is to get (or borrow) a digital multimeter and check the PSU.

Yellow wires should be 12 volts. Red wires: +5 volts, orange wires: +3.3 volts, blue wire : -12 volts, violet wire: 5 volts always on. Tolerances are +/- 5% except for the -12 volts which is +/- 10%.

The gray wire is really important. It should go from 0 to +5 volts when you turn the PSU on with the case switch. CPU needs this signal to boot.

You can turn on the PSU by completely disconnecting the PSU and using a paperclip or jumper wire to short the green wire to one of the neighboring black wires.

This checks the PSU under no load conditions, so it is not completely reliable. But if it can not pass this, it is dead. Then repeat the checks with the PSU plugged into the computer to put a load on the PSU. You can carefully probe the pins from the back of the main power connector."

 

[kaschenberg]

I checked some wires on the PSU as suggested above.

Blue wire: was giving somewhat irratic reading of -10 to -11.8V.
Gray wire: NEVER did anything - tested while switching the computer on with the switch and never saw any voltage.
Yellow wires: were giving +12V.
Violet wire: was reading ALL OVER THE PLACE.

I'm going to go out on a limb here and say it's the power supply. It was purchased in 2008 so I figure 3 years on a cheap Raidmax is to be expected. It does have a slight smell to it but nothing overpowering like when my Thermaltake went out.

I suppose I'll head to the local Best Buy and pick something up to finalize my findings then order from Newegg/Tigerdirect.

 

[kaschenberg]

I wanted to update this:

Bought a thermaltake 430w PSU - just installed it. It's back up now!

Thanks for the help guys!