System boots only if 4 pin +12V is plugged out, is this a likely mobo or PSU problem?

[c627627]

System boots only if 4 pin +12V is plugged out, is this a likely mobo or PSU problem?

Only after I plug out the 4 pin +12V does my system power up.


I don't have another PSU with a 4 pin to try to see if this is a PSU or a mobo problem.


I suppose running this without plugging in the 4 pin isn't going to be too bad, but I'd sure like to know if it's the mobo or the Antec TPII-380 PSU...
_____________________
AMD Athlon XP 2500+ AXMH 2500 FQQ4C
IQYHA 0348 SPMW
2 x 512MB Centon PC3200 (Samsung chips) @ 9 4 4 3
[200] FSB x 12 = 2400 MHz @ 1.85 Vcore with memory frequency at 100% [200 FSB] @ 2.90 Vdimm and 1.8 Vdd
Epox 8RDA3+ v2.1, BIOS 07/29/2004
Thermalright SLK-900A with variable speed 80x25mm Thermaltake Smart Fan 2
AIW 9600XT 128MB; Antec SX-835II case ; 380W Antec TruePower2 TPII-380
Five 80x25mm Case Fans

 

[CrackerD|ce]

If you have access to another comp. why not just try it on that? That would be a easy way to do it.

 

[c627627]

No kidding. I have another mobo but it has no 4 pin connector.


Yeah, that's what I need to do, get a hold of another mobo or another PSU with a 4 pins to tell which one of those is out. There's no way around it.

 

[The Coolest]

I what's the deal with plugging the 4 pin connector and leaving it?
Also I see that you don't have an Abit board, but my NF7 ran w/o the 4 pin cable plugged in just fine for a few years.

 

[c627627]

I what's the deal with plugging the 4 pin connector and leaving it?

Hi, I don't know what this question means, can you reword it please?

 

[Oklahoma Wolf]

Could be either PSU or mobo... both Epox and Antec are known for developing bad capacitors after a while. I'd inspect the board for bad caps for sure, and look through the fan on the Antec for the same in there.

 

[KillrBuckeye]

You probably wouldn't make a n00b mistake like this, but when I built my first 939 rig whose mobo had a 20-pin power connector and a 4-pin +12V connector, I mistakenly plugged in the square 4-pin connector that separates from the 20+4 modular connector. I didn't even realize that the PSU had another, separate 4-pin plug for +12V. The symptoms were a failure to power on: the fans would jerk, but then immediately stop as overvolt protection kicked in. Just thought I'd share this in case you're dealing with your first 20+4 pin PSU and/or mobo with 4-pin +12V connector.

 

[The Coolest]

Hi, I don't know what this question means, can you reword it please?

Sorry I misread "plugged out" as "plugged in".
So it only boots if the 4pin auxilary cable is disconnected?

 

[c627627]

Big thanks to this guy KillrBuckeye for posting in this thread:

You probably wouldn't make a n00b mistake like this, but when I built my first 939 rig whose mobo had a 20-pin power connector and a 4-pin +12V connector, I mistakenly plugged in the square 4-pin connector that separates from the 20+4 modular connector. I didn't even realize that the PSU had another, separate 4-pin plug for +12V. The symptoms were a failure to power on: the fans would jerk, but then immediately stop as overvolt protection kicked in. Just thought I'd share this in case you're dealing with your first 20+4 pin PSU and/or mobo with 4-pin +12V connector.

This is EXACTLY what my problem was. It went away after I plugged in a separate 4 pin connector tucked away with all the other connectors not used on this mobo.


I'm sorry, how can you not instinctively plug in the two together when 20 and 4 connectors are right next to each other and 20 and 4 Antec cables are taped together right next to each other?


How can you not expect a massive number of RMA returns on account of designing it like this?

 

[KillrBuckeye]

Hey man I'm glad I could help! If you look closely at the male/female plugs for the 4-pin connectors, you will see that only one of the 4-pin connectors matches the female plug in the motherboard. The unfortunate thing is that you can EASILY get the wrong one to slide in with very little force. It's a very good thing that most mobos and PSUs have built-in overvolt protection, or we would be seeing a lot of RMAs as you mentioned. Here is my thread from last year when I was experiencing the same problem!

http://www.ocforums.com/showthread.php?t=403722

 

[Gautam]

Let the record show that c627627 is officially a n00b.

This is yet another reason to hate multiple +12v rails. If there were a single rail then it wouldn't matter which you plugged in. (In theory of course)

 

[c627627]

In the movie Slingblade, Karl's coworkers could not figure out why a lawn mower won't start even though nothing appears to be wrong.

Karl walks over to the mower and immediately looks in the gas tank:
Y'er out of gas... mm-hm.

 

[Gautam]

Seriously though, this is something that Antec needs to be much clearer about. Though they're thoughtful enough to tell you that its necessary to open your case in order to install their power supplies (step 2, owners manual), yet this is the closest they come to explaining the 4 pin connectors:

Connect the 24-and-20-pin Main Power Connector and the 4-pin +12V Connector to your motherboard as needed.

"As needed"...not terribly descriptive in the slightest.

http://www.antec.com/pdf/manuals/truepower2.0_En_Manual.pdf

I think its time for you to raise a ruckus again.

 

[ScottinIndy]

In the movie Slingblade, Karl's coworker could not figure out why a lawn mower won't start even though nothing appears to be wrong.

Karl walks over to the mower, immediately looks in the gas tank:
Y'er out of gas... mm-hm.

Now that was funny!!

 

[c627627]

I think its time for you to raise a ruckus again.

Of course.

My pet peeve is when engineers and designers don't realize that majority of their market doesn't have a slightest clue about electronics yet engineers go out of their way to make their lives miserable with designs like that coupled with manuals that are clearly written with the assumption that reader has identical level of understanding as the designer himself.

 

[Gautam]

Steps 1 and 2 make it seem like they're inferring that the reader has the level of understanding of a cucumber though.

1. Disconnect the power cord from your old power supply.
2. Open your computer case.

 

[c627627]

Yes, meanwhile they left out the part that matters.

On the subject of raising a ruckus:

I posted here, post #22 and #23:
http://www.ocforums.com/showthread.php?t=465608

It's a thread about how even the most determined sometimes may not get results after 'raising a ruckus.'