Power supply problem...help! 6

[DJCyber2101]

OK I am just replaced a case and power supply for a client because system stopped powering up at all.

Installed MB into new case made sure there were no shorts on the case. connect HDD, floppy etc. via IDE Cables.
Connected power and reset switch, HDD LED etc. Plugged in power plug to MB(ATX). Plugged in Monitor, Keyboard(PS2), Mouse(PS2) and power cable. Hit power switch and system powers on for about 1-2 seconds then dies. Power in not even on long enough to turn on monitor. If I unplug and replug in the power cable and wait for 5 minutes I can power on for about 1-2 seconds (same as above). Any suggestions?

Ken

 

[torturedmind]

it might be that the problem is not your psu but some other hardware instead - maybe mobo, cpu, etc. you may want to do trial by elimination in such case.

hope this helps. peace!

kilroy
philippines

"Illegitimis non carborundum!"

 

[DJCyber2101]

OK Pulled CPU and RAM and tested them in my system...they worked well. I will not put my MB into the new case just in case there is a problem with the PS I want to spare my MB.

Ken

 

[BadBigBen]

Hola, check the FSB, evtl. clear CMOS first (some mobos don't like being moved, ie from power), then check the HS fan if it is sitting correctly and that the FAN is operating normaly... Check seating of GFX card, remove the PWR switch and bridge with a screwdriver to turn on PC (this will illiminate the PWR switch as a possible Prob, if the PC POSTs)...



Ben

If it works don't fix it! If it doesn't use a sledgehammer...

 

[DJCyber2101]

Cleared CMOS, heat sink fan OK and seated proper, On board Video so no problem there. Shorted power button...OK ther also.

Ken

 

[franklin97355]

Take it all out of the case and test it with only CPU and memory.

 

[DJCyber2101]

Did it...not dice

Ken

 

[paparazi]

These symptoms usually indicate one of the following:
1) You have connected the CPU fan to the system fan header by mistake (CPU fan header needs to sense a spinning fan or will shut down the PC)
2) The heatsink is fitted 180degrees out? and to all intense and purposes everything looks fine BUT!!! the heatsink doesn't quiet sit squarely on the CPU core so overheats very rapidly (a few seconds) reaches it's thermal cut off point and turns off (don't forget thermal paste!!!)
3) You may have one too many brass standoff mounting points fitted or one in the wrong position so shorting out the motherboard to ground.
4) A plugged in device (CDrom, PCI card, Hard drive) has gone bad and causing a partial short.
Pull out and disconnect all addon cards, CDroms, HDD's etc and see if it posts then.
5) Front side bus jumpers (if the motherboard has them) are set wrong but this wouldn't usually give this symptom.
Martin

We like members to GIVE and not just TAKE.
Participate and help others.

 

[jurgen36]

What CPU and speed, how big is the PSU, is it a Prescot chip?
If Prescot than PSU minimum 400 watts. Regards

Jurgen

 

[DJCyber2101]

OK Motherboard was simply removed from old case and placed into new case (CPU, Heatsink, Fan never had to be removed). The motherboard was tested on a rubber tech mat wit just the power supply and the On/Off switch attached(no IDE Drives or cards) Video is on board so no need to test it. Bus jumpers were not moved at all (or any jumpers for that matter) with the exception of the JP1 which is the CMOS reset jumper and it has been returned to it's original position.

Ken

 

[paparazi]

DJCyber2101
Have you tried pulling off the IDE cables and molex power leads to HDD's and roms, plus removing addon cards?
His old power supply may well have damaged something when it failed ie: Hard drive or CDrom.
So pull off everything,just leave the motherboard, one stick of ram, PSU, CPU/heatsink/fan, with just the power connectors (main plug and P4 connectors) pull out front panel header wires (in case you have a sticking reset or power button)
Martin

We like members to GIVE and not just TAKE.
Participate and help others.

 

[DJCyber2101]

Done that .....no dice

Ken

 

[tf1]

When you switch on, do you get any beeps from the motherboard? If not, it means that POST is not even starting. This would indicate a catastrophic failure of an important component.

My guess is the motherboard must have been damaged during the swap over to the new case. To try to confirm this, disconnect everything (including power leads from peripherals) except the processor and switch on. The motherboard should give you a single bleep (confirming power on) followed by a series of POST errors beepsbecause there is no RAM installed. If it doesn't get that far, then the motherboard is most likely the problem.

Regards: tf1

 

[DJCyber2101]

I tend to agree with you in part. I know that the motherboard was NOT damaged during transfer.

The system was sent to me by my client because she could not power on the system at all. She mentions power outages and construction near her home....my guess is that the power supply died (either from a voltage spike, power outage or similar) and the PS did not properly protect the motherboard causing both the PS and the MB to be damaged. The case and PS have been replaced and each individual component has been tested and they work individually (CPU, RAM, HDD, etc)but I cannot test the MB in another system as I do not have another case and PS. Therefore; the only constant variable is the motherboard and thus the MB is damaged and is the culprit.

Does this seem to be a logical hypothisis?

I just don't want to charge the client for a new MB if it is not the problem (not a good way to keep clients).

Ken

 

[DaveFarquhar]

Ken, your logic sounds good to me, but I would test both the old and the new power supplies to make sure they can power on.

To test a power supply without a motherboard, take a paper clip and connect the pin with a green wire to any of the pins with a black wire. Flip the power switch in the back (if it has one) and the power supply should fire up. If it doesn't, then you know it's bad.

If the original power supply doesn't fire up and the new one does, then it's a very good possibility that when the power supply went down, it took the motherboard with it. But I would try to eliminate the remote possibility that your new power supply is bad before coming to that conclusion. Then if all you have is bad news, you can at least impress your client with your thoroughness.

Dave Farquhar

http://dfarq.homeip.net

 

[DJCyber2101]

Wow...I never heard of that test before..Thanks!! The new PS started and the old one did not. This tells me that the MB is toast also. Ihave ordered the client a now MB and just finished speaking with her and got a few more small upgrades for her system also.

Thanks for your assistance Dave.

Ken

 

[tf1]

Ken

Sounds like you are on the right track there: the original PSU failure must have taken the motherboard down too: so it was probably a power spike that got them.

Suggest to your client that if the mains power in the area is still poor, install a small UPS to isolate the equipment from direct mains.

Regards: tf1

 

[DJCyber2101]

Problem was solved...client is happy and I am $245 dollars richer. Thank you everyone for all you assistance. Client ended up purchasing a new case, MB and RAM from me plus labour.

Ken

***********************************
REBOOTING YOUR COMPUTER DOES NOT
MEAN KICKING IT FOR A SECOND TIME!!
***********************************

 

[evolutionary]

hmm... thanks for all the help here, as i now am having this problem.

here's my story so far.

my computer's cpu fan has been acting up lately, stopping at times and generally not working too well. i just replaced the fan with a better one, and after the install of the new fan, my computer is going through exactly the same issue - will turn on for a second or two, and thats it. no power surges or anything like the previous story.

ive tried replacing the old fan to no avail. the new fan is working like a charm until the power shuts off. the thermal paste is ok too. ive pulled almost everything from the power supply (HDD's/etc), and no dice there either.

the computer now will stay on for about 2 seconds, nothing will come up on the monitor (which is normal for the 1st 2 seconds of the boot process here), and the cd and dvd drives ' lights will come on before the power goes off. no beeps from the computer before it turns off.

i was thinking of getting another power supply today and trying it out. i tried the RAM in another computer, and its fine. i dont have another MB to try, or to put my CPU in.

specs: amd 2400+ processor, atx 400W power supply

anyone have any other tips? some good ones above.....

 

[evolutionary]

wierd. it was the fan, as i installed it according to the directions (it even has writing on the fan to tell which way it goes), but when i turned it 180, it was fine. wierd. ill be handing out some stars now.