Over Heating Case Fans

[jimmyj68]

Anyone out there who bought the new SilenX Xtrema Pro 120 mm case fans? Just installed in the front and rear of an Antec P-160 and at the same time popped in a new SeaSonic S12 500 PSU. Hooked the fans to the 3 pin connectors from the PSU that are weighted to offer a "low" voltage on two three pin connectors and one "high" three pin connector. Put the rear fan on the high and the front on a low connector. After 5 or 10 minutes running the system the strong smell of burning electrics began to fill the room. The system continued to operate normally and I could see no obvious source for the odor.

My first thought was my new PSU - a big no-no. I shut the system down removed the case side and began inspecting for damage. Sniffing and feeling brought me to the fan motor hub which was hot enough to making touching it uncomfortable. Guessing that perhaps having the front fan and the rear was loading the rear fan down, I disconnected the front fan, powered up the system and after a while the odor returned but not as strong as before.

To make a long story short, I changed the fan power source to the motherboard connection (Intel D945PSNLK) and that made no difference so my concern that maybe the psu connectors were screwed up went out the window, I switched fans and the same thing occurred. Having heard that some intel boards had faulty fan/temperature control circuits and wondered if perhaps my board was at fault - I'm finally concluding that it must be the fans. Possibly though rated for 12 volts they were labled incorrectly and the fan is rated at a lower voltage - they run much cooler on the low psu connector.

Contacted SilenX and they will send a new fan - I probably need to let them know that the second fan has the same problem. Anyone out there who has had a similar experience? I'd really like a clean bill of health for the new PSU and the motherboard.

 

[Thor86]

I have two of them in my Antec Sonata, and have no such issues. But, ironically, I replaced my Antec fan because of the same issue, it litterally burned out.

 

[potato28]

Place some oil in berings?

 

[jimmyj68]

I don't know about oiling the fan. Doesn't sound lke a good (read safe; oil flying around in your case). Besides, the first fan to overheat began to throw "oil" on the fan shroud and a small anount leaked out to the lower side of the shroud when the fan was off.

 

[potato28]

Oil wont destroy your comp. If your scared, try it outsice the case first.

 

[jimmyj68]

Here's a strange notion - - - wife was using my computer this morning and notified me she could really smell something again (she noticed it from downstairs the first time). While she was doing whatever - I removed the side of the P-160. Ten minutes or so later the fan had cooled to normal hub surface temperature and seem to be running quieter.

Does it seem plausible that the fan is trying to pull more air from the case than can be equally taken in through the front case vents? This would load the fan just as placing your hand over the intake side of a fan loads it down. Could this be the case?

Larger and noisier high speed case fans bulldoze their way through such restricted air flow problems. This fan is designed for moving a lot of air with not much of a motor turning the 7 large blades. The motor is only about an inch in diameter. With the case closed, the fan is pulling through a Zalman 9500 within a couple of inches from it and the Zalman fan impacts the SilenX fan almost like an object blocking air flow. When there was a second similar SilenX fan installed in the front fan dock of the P-160 it effectively created a high positive air pressure rating severely loading the rear fan. The little one inch diameter motor was being pushed to its limits turning those seven huge blades.

Wadaya think?

p.s. I don't want oil flying around inside my computer - - - - - nasty when combined with normal dust accumalations.

 

[Zepper]

Silen-X fans are not a good choice (third or fourth-string fans made quiet by the expedient of an internal dropping resistor). Google for numerous sob stories... In any case, they should not be put on any type of fan controller. They have internal dropping resistors and are designed to be run at the speed they are set to by that resistor.

WTTW: Beware of new fan companies making grandiose claims. Let others catch the arrows.



.bh.

 

[jimmyj68]

I don't think so.

Any "quiet" fan (relatively low RPM) is either dropping the voltage input with a resistive load or is designed and constructed from the ground up to operate at a "relatively" low rpm with 12 volt input. Second guessing SilenX, it looks like they are using a designed, small, low RPM motor turning relatively large high efficiency fan blades. It is not at all improbable that the vagaries of computer case construction and air flow was not given sufficient consideration.

I have seen a number of brands of fans that come with an optional resistive load to plug between the fan and the input power source. When these are used with the motherboard fan connectors they are usually subject to variable input (fan controller) from the motherboard as system temperature increases or decreases. The SilenX fans come with 3 pin connectors with the intent in mind to connect the fan to the motherboard connections.

p.s. again! Replaced the side cover of the P-160 and the temperature of the fan hub went up again. I'm going to replace the zalman 9500 with a Scythe ninja I have and see if it makes any difference. I'm going to use the ninja without a fan.

I've long ago forgotten the formulas for determining voltage drop, current drop etc. across a given resistive load, but I believe I do recall that the resistive load cares not a whit about how the input voltage varies. It simply drops a lower voltage as the input voltage decreases. Commonly, fans are connected to drop 12 volts to either 7 or 5 volts depending on how slow you can stand to have your fans turn and still reasonably keep temperatures down. So, probably, a fan with a built in drop to seven volts will not run if the input is seven volts - if it is the expected 12 volts it will run at seven as the user wanted.

 

[Zap]

When fans start to die or get noisy, basically the bearings are drying out or disintegrating.

Oiling fan motors is a fairly common practice to extend the life of fans that are getting noisier or starting to die, just peel back the sticker on the frame side of the fan hub and underneath will be a round rubber plug. Remove plug and put a few drops of multipurpose oil in the hole. Put plug back in and replace sticker (or cover with tape). Good as new, kinda. Seriously, it works. BTW, use compressed air to blow out any dirt first.

When fans start dying, the motor gets hotter. Also, doesn't resisters get hot?

 

[jimmyj68]

There are no resistors external to the fan, and they are brand new delivered in there little plastic strongboxes last week.

I removed the Zalman 9500 fan (and motherboard so as to put the bottom plate in for the Scythe Ninja 755 attachment bracket) and put everything back together again with the Silenx fan still at the rear and the second Silenx fan reinstalled at the front. The system is idling at 46 degrees with just the Ninja and no auxiallary fan added. it goes up to 58 when playing Battlefield Vietnam (is that a stressed game?). Think I'll try my Microsoft Flight Simulator. I know it can heat things up.

 

[Zepper]

Probably soldered to the piece of PCB that's under the label where the leads attach. Could be an under-spec resistor - they have to maximize their profit wherever possible...

.bh.