Swapped PSU fan never starts. Is this safe?

autoboy · Post by **autoboy** » Fri Aug 24, 2007 12:46 pm

I checked out my HTPC the other day to swap out my 2600pro that didn't work right and put my 7300LE back in. What a relief from the terrible color that the 2600pro had. Anyways, I found that the grill on the back of the PSU was not warm at all. I wondered what was up so I plugged it in without the cover on and the fan would not start. It has probably been running like this for almost a year because I felt no heat on the fan grill a long time ago but forgot about it and never checked it out.

The system:
Antec Truepower 430W w/low speed 120mm Yate Loon swap (this started just fine when i did the swap)
NSK2400 case
athlon64 S754 3200+ 90mn Venice core at 1.1V
Nvidia 7300LE
Biostar Tforce 6100
2 3.5" harddrives
Sits in an enclosed HT cabinet open at the back with rather poor airflow that has never caused a problem so I don't worry about it.

This system proably uses about 75W at full load and it is always at full load because I fold on it 24/7. The power supply case was not particually warm to the touch, only directly on the side near the heatsinks. It did not smell hot or show any signs of distress. The entire system has been absolutely stable, more so than any of my other machines and I can't remember a single time the machine ever froze up. It looks like the power supply is working only on convection currents. The air is pulled in from the back grill and exhasted out the "intake" PSU grills on the nsk2400 and this is why the PSU grill is not even slightly warm to the touch.

Should I be worried about this PSU failing, or overheating and causing a fire or something? I would think that if the PSU got hot enough the voltage on the fan would be enough to start the fan and it would cool itself off. I have heard of others with a similar problem, but their PSU always eventually got hot enough to start the fan, cool off the PSU, and then the fan would always run. I have never heard of one never starting, but the temperature of the psu in that enclosed space of the nsk2400 is really not high enough to cause concern, and it appears to be working just fine. Is there anything I should worry about. I'm thinking about another swap to a medium speed fan like the scythe s-flex 1600 rpm version just to be safe.

mr. poopyhead · Post by **mr. poopyhead** » Fri Aug 24, 2007 4:24 pm

does the PSU have over-temperature protection? if it hasn't kicked in already, i wouldn't be too worried... especially if you say that it's been running like this for some time now...

autoboy · Post by **autoboy** » Fri Aug 24, 2007 5:48 pm

It is a temperature controlled fan. With a finger push the fan starts up so it works. It is an Antec Truepower 2 that I found for $20 on sale and I decided to pick it up. I assume it has thermal protections, but I would also assume that if the power supply is getting hot, it would ramp up the voltage on the fan to start it. Could it be a current controlled fan controller?

Anyone else? I'm not sure I trust someone named mr poopyhead with a potential fire hazard.

Fayd · Post by **Fayd** » Fri Aug 24, 2007 6:28 pm

i have a smartpower 450 that the rear fan doesnt run on.

i dont really know what to do about it. i never feel air really coming out of it, but it hasnt failed yet.

i guess i'll keep letting it keep on.

maybe i should email antec about it. :/

Acreo Aeneas · Post by **Acreo Aeneas** » Fri Aug 24, 2007 8:38 pm

I would do some research on the TruePower 2 series from Antec if you want to know more.

From prior experience and research, I would not be concerned about your Antec TP2 PSU failing. Unless the ampage draw is very near or over what is rated/labeled for the +12V rail(s) on the side of the PSU. In which case, I would then worry about the PSU failing. Otherwise, I don't think you'll draw over 14A on the +12V rail(s) even folding 24/7.

If you want to ensure that the PSU or parts don't burn out, then install a UPS on the machine and hook the power into a surge protector (if there isn't one built into the UPS - and most should have one built in).

autoboy · Post by **autoboy** » Fri Aug 24, 2007 9:15 pm

Acreo Aeneas wrote:I would do some research on the TruePower 2 series from Antec if you want to know more.

From prior experience and research, I would not be concerned about your Antec TP2 PSU failing. Unless the ampage draw is very near or over what is rated/labeled for the +12V rail(s) on the side of the PSU. In which case, I would then worry about the PSU failing. Otherwise, I don't think you'll draw over 14A on the +12V rail(s) even folding 24/7.

If you want to ensure that the PSU or parts don't burn out, then install a UPS on the machine and hook the power into a surge protector (if there isn't one built into the UPS - and most should have one built in).

Did you read my post? I'm on a system that uses 75W at full load. I am not even close to maxing anything out. The fan doesn't spin on it because I did a fan swap and the starting voltage of the fan is higher than the starting voltage of the power supply fan controller. I am concerned that the psu might overheat, but I'm really kinda interested in the fact that it can run passively for a year without problems. I'm asking everyone for their advice to make me a little more confident in the passive power supply that is not supposed to be passive. At 75W load and 65% efficiency the power supply puts out 30W of heat which is not inconsequential and should IMO heat the heatsinks up enough for the psu fan to turn on but that is not happening.

fjf · Post by **fjf** » Sat Aug 25, 2007 12:51 am

With such a low load your are probably safe. The key word here is : probably. If this bothers you, change the fan to one that starts. If you are happy with it, don't.

jaganath · Post by **jaganath** » Sat Aug 25, 2007 1:55 am

obviously it would be safer if the power supply was cooled by the fan. even if the PSU doesn't feel hot, heat is pretty much the only factor in the lifespan of PSU components, so cooler is better. however since the psu was cheap you could indulge your curiousity and see how long it lasts like this.

autoboy · Post by **autoboy** » Sat Aug 25, 2007 6:50 am

jaganath wrote:obviously it would be safer if the power supply was cooled by the fan. even if the PSU doesn't feel hot, heat is pretty much the only factor in the lifespan of PSU components, so cooler is better. however since the psu was cheap you could indulge your curiousity and see how long it lasts like this.

Yeah, i'm kinda intrigued by it and I want to see if it affects it in any way. I really don't want to burn my house down though.

Acreo Aeneas · Post by **Acreo Aeneas** » Sat Aug 25, 2007 12:01 pm

autoboy wrote:
Acreo Aeneas wrote:I would do some research on the TruePower 2 series from Antec if you want to know more.

From prior experience and research, I would not be concerned about your Antec TP2 PSU failing. Unless the ampage draw is very near or over what is rated/labeled for the +12V rail(s) on the side of the PSU. In which case, I would then worry about the PSU failing. Otherwise, I don't think you'll draw over 14A on the +12V rail(s) even folding 24/7.

If you want to ensure that the PSU or parts don't burn out, then install a UPS on the machine and hook the power into a surge protector (if there isn't one built into the UPS - and most should have one built in).
Did you read my post? I'm on a system that uses 75W at full load. I am not even close to maxing anything out. The fan doesn't spin on it because I did a fan swap and the starting voltage of the fan is higher than the starting voltage of the power supply fan controller. I am concerned that the psu might overheat, but I'm really kinda interested in the fact that it can run passively for a year without problems. I'm asking everyone for their advice to make me a little more confident in the passive power supply that is not supposed to be passive. At 75W load and 65% efficiency the power supply puts out 30W of heat which is not inconsequential and should IMO heat the heatsinks up enough for the psu fan to turn on but that is not happening.

Yes, I did read your post. I still can't see how your system is only drawing in 75W (unless you also clocked down the speed of your CPU) while folding 24/7. You only mentioned that you clocked the Venice's voltage down to 1.1 from 1.4.

Anyways, a simple solution to your worry about a possible PSU overheat. Since the PSU fan doesn't start, you can rig up a 120mm by the interior vent of the PSU, voltage mod it so it spins at the lowest, and then you'd have some airflow past through your PSU.

autoboy · Post by **autoboy** » Sun Aug 26, 2007 1:11 pm

Well, considering that a Venice single core 90nm cpu at only 2.2ghz uses maybe 40W max full load even with stock voltage, a .3V undervolt can bring that down to 30W. The 7300LE is at idle 95% of the time and uses maybe 10-15W at full load, the motherboard is a 6100 board that doesn't use too much power, and the two drives are 10W each, yeah, 75W is about right. Most computers output between 60-150W so there is really no way to max out a 430W power supply except with overclocks and dual graphics.

Putting in another fan would work , but maybe a I could just rig up the fan to a hard 5V and that should take care of things right?

Elixer · Post by **Elixer** » Sun Aug 26, 2007 2:52 pm

There are 3 possibilities as to what's happened.

The most likely is that the fan has been used and now has some ware, and due to the low voltage when the PSU isn't very hot, no longer starts at the minimum voltage. Heating up the PSU however will cause it to start.

The second is that the fan has fried. This has happened to me before when playing with PSUs (think I shorted +12V to ground, PSU fan died, but PSU is still working). I replaced the fan and everything was fine. Or the fan has been getting a low 4V and not starting because the PSU wasn't hot enough and over time that killed the fan. Normally fans don't mind this though. Every now and then, fans do "just die." I've seen it while working in a computer room.

The third unlikely possibility is that the PSU fan controller has died, and your fan is fine, it's just the controller that's gone. If this is the case, you should just wire your fan to 5V and forget about it.