Need quick answer on PSU diagnosis question

[deadlock]

After about 18 months my PC simply wouldn't turn on with the first hit of the power button, and it would take a few jabs to get it going. It got progressively worse until last week, which is when it stopped working altogether.

I tested the PSU by shorting the power pin with a GND pin, and it turns on fine. While it is on, I tested the (idle)voltages using a multimeter and they also read just fine.

So I figured I must have a bust MoBo. Cue a new MoBo, and I get the same problem.

The Standby LED on both boards turn on, and the PSU still tests fine, but neither board will turn on with the PSU plugged into it.

So my question is: Can my PSU turn on fine if I short it and then show correct voltages but still be bust? Like a car engine, is it possible that it doesn't spit out enough "jump" voltage to get the MoBo started? I need to be sure before I go out and buy a new PSU as I live in a country with no return policy.

What sucks is that because all the AMD boards on the market are now DDR2 and AM2, I had to get a new CPU and RAM along with the new board, and it turns out that the board may not have been broken in the first place.

Any advice appreciated.

 

[GalvanizedYankee]

Remove and open the PSU for inspection. You will be looking for bulged, tilting(bottom bung pushes out) or vented capacitors. Gently push the output wires aside and look at the caps buried under the wiring. These are the secondary caps and generally are the ones to cause issue.
If your PSU is an Antec TruePower or SmartPower it will be populated with Fuhjyyu capacitors. These bad-boys are infamous and crap-out under heat pretty quickly.
If your PSU has bad caps it can be recapped and put back into service. For futher info do some reading at http://www.badcaps.net/ If you register there, give the referral to Galvanized, thank you.

Open and inspect the unit.

 

[deadlock]

Galvanized, thanks so much.

I opened the baby up (Antec TPII, as it so happens!) and took a good look inside. Two of the small caps (about a half inch high) on the main board have a little brown stuff seeping out right at the top, in the middle of the "pie" if you see what I mean. I guess these are burst caps?

Then a couple of the taller inch-high capacitors directly underneath the power cables have a slight bulge at the top, and one of them is tilted.

I did the pin-short test again but this time with a HDD attached, and it turned on and the drive spooled up just fine.

Would this test and the apparently dead caps still account for my PC's failure to boot?

Thanks a bunch!!

 

[GalvanizedYankee]

YES! Read me http://www.theflyingpenguin.com/ > My Blog > 9/17/05, about halfway down the page.
I do hope you have all your important stuff backed up.
It was no guess on my part that it was a TP or SP. *shakes head in disgust*

Contact member AntecCSR or Antec, Fremont, CA for an RMA. Then keep it as a spare.
Buy an Enhance ENP-5140GH or Silverstone Element to use.

 

[Bob Anderson]

Gavanized:

I purchased an Antec 1050B with SP 500 late October or early November 2005. No telling how long it was in the mom and pop's inventory. Naturally, I do not want to open it.

What do you think the chances are of it having those bad caps? I'm hoping the cap problem was solved by the time I bought mine.

Two good things, though, that may protect me:

My power demands on the PSU are typically 90-100 watts with the ocasional peak to 130 - 140 (according to my energy meter... handy little device).

I have a dual conversion UPS which regenerates AC anew as a perfect sine wave and noiseless.

The PSU exhausts air at or only slightly above room temp, never feels hot to the touch, and the rear temp controled fan on the PSU has never come on (this is a cool house because I like it that way).

Your comments would be most appreciated.

-Bob

 

[GalvanizedYankee]

Yeah, it has'em. Running 24/7 folding they are good for about 12~18 months, or so it seems.

The problem is heat, these cheap caps drop to their knees when subjected to heat.. Antec under-speced the cooling fan in favor of silence and the output caps are buried in the output harness, right where it's soldered to the pcb. This wiring is like they have a sweater on. Good caps, like used by Seasonic(and all they build for, minus the NeoHEs), Etasis, Zippy/Emacs, Delta and several others is about $10 per unit.

Just be aware of the issue. If it takes hitting the power button twice to power-up...New PSU time.

CWT builds the SP & TP units BUT to Antec's price point.

 

[Bob Anderson]

Thanks, and you bet I'll get a new PSU the first time it fails to power up on the first press.

-Bob

 

[Bob Anderson]

I decided not to wait, since I plan to do a complete new box after Vista SP1 anyways. So, I am ordering the Seasonic M12 500. It's a bit of overkill for me (the 500 watts), but I like all its features, and it relieves me of my uncertainty concerning the SP 500. I'll keep the SP as an emergency spare, but I doubt it will ever come to that.

Thanks to the original poster and Galvinized for getting me off my arse and doing something to head off potential PSU problems.

-Bob

 

[Paperdoc]

Hold up! I think you missed the boat and got lucky!

The original problem as described was that the on/off switch did not seem to work. At first it took several stabs to get the unit turned on, then it failed altogether. This looks to me like a problem with the push switch itself, not the mobo or PSU. That is confirmed by the fact that, every time you short the apprpriate pins, everything boots up just fine! Pull the push switch from the front of the case and check it out thoroughly. Check its cable and connectors, including the pins it fits onto on the mobo. If the switch itself can be opened up, check its parts for dirt, wear, of bad "springyness". (How technical can you get!). Or, simply replace the switch. It is just a momentary-contact pushbutton.

But you may have got lucky in your inspection of the PSU. From your description it still appears to work despite signs of significant breakdown and imminent collapse. So you may have stumbled across a disaster you can prevent! Lotsa people have not been so lucky.

 

[GalvanizedYankee]

Originally posted by: Paperdoc
This looks to me like a problem with the push switch itself, not the mobo or PSU. That is confirmed by the fact that, every time you short the apprpriate pins, everything boots up just fine.

Maybe I should have asked but my guess is the OP pulled the 20/24 pin ATX connection inorder to jump the pins for this type of crude testing. In removing this connection alot of electrical boot load was remove and the PSU did function, if you can call it that.
I respond to maybe two posts a week on this board where an Antec TP or SP is involved in a failure to boot.

The easy fix if the power button is bad is to just use the reset button, then configure the BIOS for just using one button for both functions. The reset would become the power button by switching connections at the motherboard.
The switches can arrive bad or go bad. I use a test light or ohm meter to test these switches before assembly.