Possible PSU / Mobo issue?

[Tay690]

Motherboard : M2N-SLI
Memory : 4x 2GB DDR2
CPU : AMD Phenom X4 9500
Graphics : Nvidia 250 GTS
1x Sata HDD
1x DVD Burner
1x Chasis Fan

I had a 650 W PSU that has been in this computer since it was built. I had a couple of blackouts (It was in a surge protector) and the computer began to not start consistently. It would take numerous power cycles to get the computer started and would have to be left on indefinitely.

I have since bought a 550 W PSU and plugged it in and the computer will makes noise like it is starting...but will not post and go beyond that point.

Is the 550 W PSU really not enough to power this setup?

Thanks in advance,
Taylor

 

[BigBadBeef]

Yeah looks like them' surge protectors going off, capacitors in the PSU itself must be blown, discharging too much power. Try shining a flashlight inside the PSU and see if you can spot any bloated capacitors.

 

[Tay690]

I have since checked and cannot see any bloated capacitors inside the 650W PSU. What I don't understand is why the 650W PSU (that is easily 8 years old) randomly works after numerous power cycles...and the brand new 550W PSU doesn't even post. Could it be the motherboard itself? Should I try putting the 650W PSU back in to isolate the motherboard from the problem?

 

[BigBadBeef]

Okay, I've had this problem in my old pc, and I fixed by taking everything apart, cleaning it and putting it back again. At that time I noticed that my AGP slot was a bit wonky and I had to fasten my graphics card to my case with a rubber standoff in addition to the bolt. That worked for a while. In your case, it could be anything making poor contact with the motherboard, causing improper initialization.

Do what I did.

 

[Tay690]

I have since removed the motherboard and cleaned everything thoroughly. I tried the 650W PSU again and it didn't work. Then I connected the 750W PSU from my new computer and it started the first shot but would not post. So at this point I am ruling out the PSU because it works perfectly fine in the new computer.

Could it be the motherboard? Or possibly the thermal compound between the CPU and the heatsink? (it was never changed for the 8 years I have had the computer)

 

[westom]

I have since removed the motherboard and cleaned everything thoroughly. I tried the 650W PSU again and it didn't work. Then I connected the 750W PSU from my new computer and it started the first shot but would not post. So at this point I am ruling out the PSU because it works perfectly fine in the new computer.

Using your logic, the number of possible reasons for that defect could easily be 100. Because shotguning is about replacing and changing everything only on wild speculation. Replacing good parts until something works.

What has been accomplished or learned after all that work? Almost nothing, One obvious discovery is that most all electronic failures have no visual indication. It should be obvious that thermal compound would do nothing to avert a power up. Surge protectors do not go off. Only useful recommendations occur when suspects are defined by the evidence - especially numbers.

A power system is many components - not just a PSU. With a digital meter, one minute labor, and requesting some instructions, then resulting numbers means the fewer who actually know this stuff can reply with definitive answers and useful suggestion.

 

[Tay690]

Not my first power supply issue...they are by far the most annoying to troubleshoot.

What has been learned? Well, judging on the fact that both a brand new 550W and 750W PSU have both failed to post (yet work in my other PC) it is almost certain that it is NOT a power supply issue...so we have now ruled out the most annoying of hardware troubleshooting issues.

Thank you for your constructive response. If I had the tools to do what you were suggesting...I would have been doing it before endlessly swapping power supplies, pulling my motherboard out and wasting 2 hours of my life.

 

[westom]

Not my first power supply issue...they are by far the most annoying to troubleshoot..

Power supply issues are simple. But facts must be learned. For example, normal is for a defective PSU to work in another system. And normal is a good PSU to fail in another system. Therefore swapping may even create confusion. Numbers mean an immediate answer - without speculation, doubts and disconnecting anything.

Second, a PSU is only one component of a power system. Those other compoonents are also why some perfectly good PSU can act defective in some systems. Only numbers report on the entire system.

Third, required tool is maybe $5 in Harbor Freight or $12 in Walmart or a few quid in Malpin. That tool has even been seen on some grocery store shelves. Or can be borrowed from a friend since even auto mechanics use them.

A PSU only might be good. Rest of that power system remains unknown. Nothing definitive has been learned. Probably good and good with doubt are two completely different answers. Answers that are only maybe good can be annoying.

If a power power system is only maybe good, then just keep replacing good parts until something works.