PSU issues and burnt atx connector

[PickledSheep]

Recently my computer has been very unstable. It would randomly reboot
in windows, or even in the bios or during post. I had felt it was
possible overheating. It has recently gotten much worse, today to the
point where it would no longer post. I immediately began to remove
the motherboard to make sure the heatsink was properly seated on the
cpu. While removing the 20 pin ATX cable from the motherboard i
noticed four of the connectors (all red cables) were burnt
and slightly melted along with the connector on the motherboard side. I removed the psu
from the case, and also noticed a strange melted sort of substance
through the fan opening.

I put the psu out of my parents computer (generic 350W PSU, 15A on 3.3V, 25A on 5V and 13A on 12V) in my computer, hooked it back up (except for the CD drives, also i clocked it to the stock voltage) and powered up. It seemed to work fine. Within 5 minutes it produced a nasty electrical smell, and some melted guck appeared inside. I'm not sure if this melted guck is some sort of adhesive, or something similar i am unaware of. It is a milky whiteish yellow, and it has appeared at the bottom of a large capacitor and all over the inside of the SmartBlue.

My question is, did my computer just crush both of these power supplies, and i just need to buy a better one (considering a neopower, modstream or powerstream). Or is there actually something wrong with a piece of my hardware, that is causing the PSU's to overvolt? Also what caused the burnt atx connectors? I fear that replacing just the PSU will not solve the problem, and the the mobo or something else may be the issue. Any suggestions?

Computer specs:
AMD Athlon XP 2500+ (overclocked to 3200+ at stock voltage)
ASUS A7N8X Deluxe Motherboard
512MB Corsair XMS RAM
ATI Radeon 9800 Pro
2X80GB Western Digital HardDrive
BenQ DW1620 DVD Burner
BenQ CD Burner

 

[Operandi]

Just so I'm under standing all this... Your system killed 2 PSUs?

BTW, welcome to Anandtech.

 

[nortexoid]

if Hume has taught us anything, it is that we can never be sure of the causes of your computer's misfortunes. so, try another PSU and pray that it works. if it does not, can try another PSU. again, if that does not work, try another PSU, and so on ad depletio-de-moola. after several thousand PSUs, you might have good reason to believe it's not the PSU, but you surely cannot infer from brute enumeration of instances that the cause is not the PSU.

i bid thee good luck.

 

[Zepper]

Most good Socket-A mobos will have both a 20-pin ATX connector and a 4-pin square, P4-12V connector that looks similar to a 4 pin section of the ATX connector. Both must be used. What has happened is that the 5V wires were overloaded and became loose from thermal cycling. As they became looser, the resistance went up more and more and the connections kept getting hotter - hot enough to soot and/or melt the plastic housings.
. At a minimum, you will need to clean the ATX contacts both male (mobo side) and female (psu side) with good contact cleaner - I use Caig Labs Deoxit and a folded pipe cleaner. You may also need to tighen the female contacts a bit (if you need to get a new PSU, you won't have to do that part).
. Generally any decent PSU won't self destruct like that. An overcurrent condition should cause the affected rail(s) to shut down. But if there has been actual melting or capacitor failure inside, they will need to be replaced. Some use hot glue and other insulating and locating materials that look like they might have melted but it wouldn't really be from the PSU overheating. You would have to know how they looked originally to tell the diff. Send them back to their respective mfr's for inspection if you aren't sure.
. From what I understand, the Radeon 9800s have their own on-board power connectors which also must be used.
. And if you just recently assembled that system, be sure you don't have any mobo mounting posts where they don't belong and possibly shorting out the mobo. On the A7N8X there should be nine mounting points in three (front to back) rows of three posts. You mobo will have silver rings around the proper mounting holes and they will be specifically pointed out in the manual. Extra posts will either unscrew or snap out of the mount pan.
. You didn't mention the make/model/wattage of the first PSU, but the second one is definitely NOT up to handling the system you have listed. It needs a VERY sturdy PSU.
.bh.

 

[Zepper]

From the pix of the A7N8X on newegg, the power circuitry looks poorly designed. There is no P4-12V connector and the ATX socket is placed well away from the on-board regulators. If there are any supplemental power connector(s) on that board, make sure you supply power to them as instructed in the mobo manual.
.bh.

 

[PickledSheep]

Ok, i have been running this system for over a year with an Antec SmartBlue 350.
As for the second power supply, i didnt wreck it, i just smelt electrical so it was obviously overeheating so i powered down immediatley. I'm thinking this psu just couldnt handle my computer. This psu still works fine in another computer. It sounds like this "guck" im seeing inside the psu may in fact be adhesive, and in antec psu's this adhesive supposedlys browns, which is what im seeing through the fan hole. It doesnt look like the stuff leaking out of the caps on BadCaps. Also these problems have arisen recently when i put in my new benq cd-rw and dvd-rw drives.

So i guess im kind of lost. Should i try and warranty this 350 watt smartblue (or will a replacement just have the same problems), just order a new psu, or replace the motherboard as well.

 

[Matthias99]

Even if you try to overload a PSU, it normally won't melt down and self-destruct. Your motherboard is most likely damaged in some way.

 

[Zepper]

I would try the contact cleaning/tightening routine to see if that brings things back to life. After cleaning you can improve the contacts by using Caig Labs Pro Gold. It is a contact enhancer/lubricant/protectant and cleaner (but cleaning is only a minor function of PG). Contacts enhanced with Caig Labs products have been able to carry twice or more of their rated current. And every now and then check the ATX connector with your finger - it should never get more than moderately warm. If it again gets hot, do another clean/protect/tighten cycle. Or just RMA the thing - even Antec is probably using cheap contacts in their PSUs ATX connectors like everyone else instead of the good stuff like real Amp or Molex brand contacts.
. You can point the finger at substandard contacts that loosen from thermal cycling as the culprit - or maybe the PSU cabling was assembled on "Friday" and the wires weren't crimped to the contacts properly. It worked for me with Enlight... There have been a number of posts here about this effect. The pix with the latest example prior to yours showed the ATX shell on the PSU side had completely melted away around the 5V pins. :shocked:
. So until someone can prove otherwise, I'm laying this problem to cheap and/or poorly assembled contacts in the PSU ATX connector. The high currents thru the 5V lines can't tolerate shoddiness in that area at all.

.bh.

The :sun:, the :sun: !