Replace stock heatsink fan in Dimension 8400 possible...

[wildwolf]

I've got a dimension 8400 computer that has a Dell custom 4 wired exhaust fan that cools the CPU. Well, obviously, it's not doing a good enough job at low rpm's as any task (such as opening firefox, email app, or even worse, a 3D application) will cause the fan to ramp up to high RPMs. It's unbearable to hear and unbelievably loud. The fan can't be removed, as there's a sensor on it that the motherboard reads: w/o fan, system won't boot.

I have seen that many have problems with this really loud fan. I have seen somebody modify brackets to a socket 775 heatsink/fan unit (Zalman something...and this IS a socket 775 CPU) so that it would fit/replace the stock heatsink. They also had to modify the huge CPU fan and move it back from the newly installed heatsink/fan.

I'd rather not be having to modify a new heatink/fan just to get it to fit in the case. However, I will if nobody can give me some pointers on some good cooling and hopefully quiet heatsink/fan units that would mount pretty much straightforward into the Dimension 8400.

Does anybody have any suggestions?

OR...does anybody know if I can mount a name brand motherboard into this case without any problems? (Asus, Abit, Shuttle, etc.)

 

[MustISO]

The reason it says the system won't boot may be because the BIOS reads the RPM sensor and if it detects no fan, it won't boot. As long as you plug a fan in it should be fine.

 

[wildwolf]

It's a special 4-pin connector on this specific fan. I've never encountered system fans with 4 pins, have you?

Looks like I'm SOL anyways, as the new heatsink/fan I just picked up at Compusa won't work. Dells seems to have drilled their PCB holes for the retention bracket at what appears to be nonstandard places. Thus, I have no way to secure the new heatsink/fan...and what a shame. I think this new unit would have done nicely. Zalman 7000B-CU with required ZM-CS1 clip support for socket 775.

The ZM-CS1 clip was required to allow the 7000B-CU to attach to the socket 775, however, it's massively larger than the holes for the socket 775 on this dell.

 

[FlyingPenguin]

Order a new fan from Dell. 8400's are VERY quiet. If the fan is constantly ramping up to high speed then it's probably defective (probably a bad sensor on the fan). I've seen this with a few client's systems. Assuming you have the unit in an airconditioned room, you should barely hear the fan running most of the time.

If the unit is still under warranty they'll overnight the fan to you for free.

Also a quick Google search turned up a few places that sells surplus fan & shroud assemblies for Dell 8400's. Here's one: http://www.pcsurplusonline.com/viewprod.cfm?ID=5353

I'd check ResellerRatings.com before ordering from them. I've never dealt with them.

You'd probably find them on Ebay too.

Hope this helps...

 

[LiLithTecH]

How much room do you have BEHIND the case?

The heatsink that Dell uses is a heatpipe design very similiar to Zalman's.
If the PC does not have enough of output, the noise level on the system
would increase (basically backflow of the airflow). Since the airflow is
not sufficient, the sensor(s) (there are 2) see the higher temps and increase
the RPM to compensate, making the stituation worse.

You need atleast 8-12 inches min. of unblocked space behind the PC.

 

[wildwolf]

System's got 74 more days on warranty, and I just got off the phone with them. They're shipping me a new fan. Hopefully that fixes the issue.

If not, I'll see if I can mount another motherboard in this case.

Roger

 

[FlyingPenguin]

It is NOT supposed to be noisy under normal operation at a normal room temp, and you should have an ON SITE warranty.

If the fan doesn't solve the problem make them come out and fix it. You may end up getting the entire mobo/CPU/heatsink/memory replaced. That's what they usually do. The on site techs don't get into troubleshooting anything mobo reated, they just swap it out and send the old hardware back to the factory.

That's a nice system with the right video card in it - probably what I'd buy right now if I didn't feel like building and I don't have much time for building anymore. The 8400 is essentially the same computer as their high-end Dimension XPS gaming system with a diffferent case and a slightly lower wattage PSU. Everything else including the mobo is the same.

I have lots of clients with 8400s and you can't hear the fans running normally, so believe me something is wrong and it's fixable. I've had the occasional client with a fan that would run fast and loud and replacing the fan usually fixes it.

 

[wildwolf]

I applied some arctic silver...and you can slightly hear the fan running during idle.

If I choose "setup" however (instead of windows) it runs like a banshee. If I boot windows, and open a couple explorer windows. you can hear it rev up for a couple minutes. If I fire up a game (something as old as Quake2), it runs like a banshee.

There's NO way I would a machine this loud as a desktop machine. It's under warranty yes, but it is no longer the original CPU in the machine (which should NOT affect a fan's performance. I bought the machine from a guy on the forum here and he's fully transferred the warranty to me already. Other than the loud fan, I'm happy with the purchase.

Oh, and "on site" warranty won't do me much good. I'm typically busy M-F 8-5 pm...unless you know their techs will come out around 6:00 pm....I requested and assured the Dell support that I'm quite capable of replacing the fan myself (which I am), and if this doesn't fix the problem, I will try to replace the heatsink. They can't, nor would I expect them to, replace the CPU.

 

[imported_Kensai]

Originally posted by: wildwolf
I applied some arctic silver...and you can slightly hear the fan running during idle.

If I choose "setup" however (instead of windows) it runs like a banshee. If I boot windows, and open a couple explorer windows. you can hear it rev up for a couple minutes. If I fire up a game (something as old as Quake2), it runs like a banshee.

There's NO way I would a machine this loud as a desktop machine. It's under warranty yes, but it is no longer the original CPU in the machine (which should NOT affect a fan's performance. I bought the machine from a guy on the forum here and he's fully transferred the warranty to me already. Other than the loud fan, I'm happy with the purchase.

Oh, and "on site" warranty won't do me much good. I'm typically busy M-F 8-5 pm...unless you know their techs will come out around 6:00 pm....I requested and assured the Dell support that I'm quite capable of replacing the fan myself (which I am), and if this doesn't fix the problem, I will try to replace the heatsink. They can't, nor would I expect them to, replace the CPU.

BIOS = No fan speed control whatsoever.
Starting = No fan speed control whatsoever.

 

[FlyingPenguin]

but it is no longer the original CPU in the machine (which should NOT affect a fan's performance.

Umm, yes it could. If the temp sensor on the system isn't calibrated for the temp sensor on the new CPU (I really don't know if the mobo uses the fan's sensor alone or a combo of the fan and CPU temp sensor) or if it's a CPU that runs hotter than the original.


ANYWAY might have something that helps you out even if the new fan still is too noisy. Found this thread here:
http://www.daniweb.com/techtalkforums/thread8531.html

I had the same issue with a Dell Dimension 8400 - the fan drove me nuts! I bought a Zalman quiet fan and realised that there was more to it than this as Dell are a bit individual. After searching for ways to turn off the bios fan error i came up with zilch. It cannot be done.

I eventually realised that I needed to work with the Dell fan. The Zalman quiet fan was shipped with a cable that had a resistor on board to reduce the voltage. I simply added this to the Dell fan red wire to reduce the dell RPM! Silence! My fan is cooling, no errors and I can work in peace!!!

Took me 3 weeks to sort this out and the solution was a 10 minute job!

Hope this helps...

 

[wildwolf]

Looks like I'm SOL anyways, as the new heatsink/fan I just picked up at Compusa won't work. Dells seems to have drilled their PCB holes for the retention bracket at what appears to be nonstandard places. Thus, I have no way to secure the new heatsink/fan...and what a shame. I think this new unit would have done nicely. Zalman 7000B-CU with required ZM-CS1 clip support for socket 775.

Already tried that thread's advice, but couldn't find my drill bits (just moved to a new house) and besides didn't have a hacksaw nor vise to hold the brackets. Also the brackets that came with the 7000 unit I bought may have been different than the 7700 came with, I don't know.

With no way to modify the brackets, I would not have been able to mount the new heatsink/fan to the CPU.

I'm gonna go out on a limb, btw, and assume that Intel would NOT work as closely with Dell as would be required to tune/calibrate their CPU's with Dell's fans. I've read reports that replacing the fan unit fixes the problem as well, so with that in mind, if they were calibrated together....then that idea went out the window when only fans were replaced.

I have 3-4 business days for a fan to get here...if it works, great news for me. If not, I'll spend another $100, get a used namebrand motherboard, and sell this one with a "noisy" notice which includes the fan.

 

[FlyingPenguin]

Not sure if you understood my last post. Sounds like someone else with the same problem just dropped a resistor in line with the fan to lower the voltage slightly and that eliminated the noise.

At most you would need to spend the money on one of those Zalman fans that comes with the resistor and just use the resistor - save the fan for something else.

As for swapping mobos, forget it. You might as well buy a new case and build it from scratch. Dell cases are proprietary - you'll have to modify it to fit a normal mobo.

I the the resistor is the simplest solution.

 

[wildwolf]

I could do the resistor thing, but I hope it turns out to be a bad fan/sensor. If that fixes it, all is well. If not, I will use the resistor idea....if that doesn't satisfy me, I'll opt for a new motherboard (I have a spare case...just like the looks of the dell).

Thanks for the input though. I appreciate it.

 

[wildwolf]

Just my luck, wasn't the fan.

Gotta be: processor, motherboard, or just bad engineering? Surely these things aren't THIS loud everywhere. It's fairly quiet...UNTIL I fire up a game, or open a few items. After brief pause, item opening will eventually settle down the fan.

Fire up Quake2, however, and that puppy whines like there's no tomorrow.

Oh well, have already ordered additional parts to get over the Dell, and I'll soon pass it on to somebody else that doesn't mind loud systems.