No post no display

[ndoherty55]

I just installed new POWER supply and hard drive in a machine I built 3 years ago. The cpu fan does not work. Graphics card fan does work.
cd player works reads XP disk but I get no display and no post

 

[ndoherty55]

I just installed new POWER supply and hard drive in a machine I built 3 years ago. The cpu fan does not work. Graphics card fan does work.
cd player works reads XP disk but I get no display and no post

Just to add a few more things. I toubleshot according to the sticky about boot/no post problems. I went through all obvious things. This system worked fine for past 3 years until recent power/ Hard drive problems. Hard drive had bad sectors and wouldn't boot. Replaced HD, then original power supply died

Gigabyte 965pds3 MB
INTEL duo 6600 processor
oztech 2gb ddr2-800
antec p180b case
geforce gts250 graphics cardWDcaviar black 650gb new hard drive
coolmax 700w atx2 new power supply

The guts of this system are almost 4 years old, so maybe it's time to upgrade, but $ is tight and I only want to fix what's broken. I'm thinking the Mb has some problems, since cpu fan doesn't run, it spins briefly then stops when power switch is turned off!!

No beeps when power is turned on. Last time I powered on, machine powers on for a few seconds then lights up again, then shuts down, etc.

I'm beginning to think power supply is bad. Any suggestions are welcome. Thanks

 

[dEAne]

You did read the post regarding no post no display - Just the motherboard, PSU, and CPU no RAM no video card. If the motherboard has a led it should lit and the obvious beep sound indicating no RAM. The PSU's fan should spin if not then try this PSU from another computer if it works then you have a dead motherboard.

 

[jsc]

Work through our standard checklist and troubleshooting thread:
http://www.tomshardware.com/forum/261145-31-read-posting-boot-problems
I mean work through, not just read over it. We spent a lot of time on this. It should find most of the problems.

If not, continue.

I have tested the following beeps patterns on Gigabyte, eVGA, and ECS motherboards. Other BIOS' may be different.

Breadboard - that will help isolate any kind of case problem you might have.
http://www.tomshardware.com/forum/262730-31-breadboarding

Breadboard with just motherboard, CPU & HSF, case speaker, and PSU. You do have a case speaker installed, right? If not, you really, really need one. If your case or motherboard didn't come with a system speaker, you can buy one here:
http://www.cwc-group.com/casp.html

You can turn on the PC by momentarily shorting the two pins that the case power switch goes to. You should hear a series of long, single beeps indicating memory problems. Silence indicates a problem with (in most likely order) the PSU, motherboard, or CPU.

Remember, at this time, you do not have a graphics card installed so the load on your PSU will be reduced.

If no beeps:
At this point, you can sort of check the PSU. Try to borrow a known good PSU of around 550 - 600 watts. That will power just about any system with a single GPU. If you cannot do that, use a DMM to measure the voltages. Measure between the colored wires and either chassis ground or the black wires. 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.
http://www.youtube.com/watch?v=5FWXgQSokF4&feature=youtube_gdata

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.

If the system beeps:
If it looks like the PSU is good, install a memory stick. Boot. Beep pattern should change to one long and several short beeps indicating a missing graphics card. Silence or long single beeps indicate a problem with the memory.

Insert the video card and connect any necessary PCIe power connectors. Boot. At this point, the system should POST successfully (a single short beep). Notice that you do not need keyboard, mouse, monitor, or drives to successfully POST.

Now start connecting the rest of the devices starting with the monitor, then keyboard and mouse, then the rest of the devices, testing after each step. It's possible that you can pass the POST with a defective video card. The POST routines can only check the video interface. It cannot check the internal parts of the video card.