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Wavering fan -- fix?
All,
Posted this in an older thread but haven't heard much in the way of reply --
My 8400 fan has a kind of buzz to its tone that constantly speeds up and down with the slightest bit of load on the CPU.
I noticed the other night, with my iPod plugged into the front USB port closest to the case, that the wavering goes away. Even disconnected the iPod and just ran with only the cable plugged in. There is still a bit of a buzz to the fan, but not as harsh as before, and it is at a consistent speed 98% of the time.
Plugging a USB device into the back ports does nothing for the fan noise.
I thought it might have something to do with the fact that I had raised the grey cover on the front of the machine to plug in the cord and had improved airflow, but I've closed that cover now (with the cord still in the USB slot) and still the fan is now consistent.
If I unplug the USB cord, the fan starts going up and down again.
Any ideas what might be going on and what I might try next with Dell tech support to solve the fan problem? I have another fan sitting on my desk waiting to install.
Thanks and regards,
Dave
Posted this in an older thread but haven't heard much in the way of reply --
My 8400 fan has a kind of buzz to its tone that constantly speeds up and down with the slightest bit of load on the CPU.
I noticed the other night, with my iPod plugged into the front USB port closest to the case, that the wavering goes away. Even disconnected the iPod and just ran with only the cable plugged in. There is still a bit of a buzz to the fan, but not as harsh as before, and it is at a consistent speed 98% of the time.
Plugging a USB device into the back ports does nothing for the fan noise.
I thought it might have something to do with the fact that I had raised the grey cover on the front of the machine to plug in the cord and had improved airflow, but I've closed that cover now (with the cord still in the USB slot) and still the fan is now consistent.
If I unplug the USB cord, the fan starts going up and down again.
Any ideas what might be going on and what I might try next with Dell tech support to solve the fan problem? I have another fan sitting on my desk waiting to install.
Thanks and regards,
Dave
Dave, I have a 8400 also. I had a wavering fan issue and also i could open the front cover for the USB ports and the tone or wavering would get better. I think i have the prob. fixed by replacing the heat sink and the processor fan, which i went through four of them. The last i just ordered the from spare parts because i did not want to go through the hassle of tech. Support for a forth time. Many other 8400 users have complained of fan issues with their systems. Most were resolved with a heat sink and a fan replacement. Since i last replaced the parts the system has been very quiet and very little wavering. Good luck and if you come up with any thing new let us know.
dimension 8400
3gig p4, 512mem
xp home
dvd/rw,dvdrw
ati pci300JimBo_0313
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Posted March 18th, 2005 17:00
Dave,
Just to reinforce Munkie's post, I too had the whining, wailing , buzzing , vacuum cleaner noise based on CPU usage coming from my new ( 12/04 ) 4700 . After more tech chats than I care to remember and 4 fans I finally got a new heatsink/CPU/fan kit today. Took me 15 minutes to install and the problem is gone , gone ,gone.
JimBob
"Master of the Sr. Moment"- The big one -- I'm an 8400 -- it's got three copper tubes at the bottom, a big stack of aluminum fins, and then the whole thing is covered with a green plastic shroud that directs the airflow out via a fan attached to the back of the case.
I've heard on this board that cold air out = bad heat sink. Heat sink #2 definitely kicked warm air out the back, and the fan was a Nidec. Still had the wavering noise so bugged Dell until they sent a tech with a motherboard, a heat sink, and a fan. I wasn't paying attention and didn't realize until after the tech had gone that fan #3 was a Delta.
Ordered a new fan (also turns out to be a Delta) and I'm going to pop it in tomorrow afternoon. Now I'm suspicious of heat sink #3 cause there is cold air out the back, not warm. JimBo_0313
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Posted March 18th, 2005 18:00
Dave,
Which heat sink do you have .... the short copper one with the airfoil shaped fan shroud or the "big" heat sink with the copper tubes and the "boxy" fan shroud ?
JimBob- Agreed. The Delta is noisier than the Nidec fan but it's not bad -- as long as it picks a speed and stays with it. The problem is whatever is controlling the speed of the fan, and I'm not entirely sure which part is responsible for that. Motherboard? CPU? Got me. I suspected CPU, and wanted the CPU replaced anyway since if I do have a cooling problem, I'd rather replace the bugger than have it belly up on me three days out of warranty, but tech support blew me off about a new processor.
I'll just keep asking for replacement parts until something fixes it. JimBo_0313
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Posted March 18th, 2005 19:00
We could go at this forever but .... the way I got mine done was to ask for a fan and when the Bollywood tech assumed I was stupid he just automatically assigned a Dell ( Bantec ) techie to come out and install it. When the tech heard the fan noise he agreed that it needed the fan/CPU/heatsink package and ordered it direct from Delltown. He had the Dell parts guy on my speakerphone and there was not even a question about what was needed. I know this is like beating a dead horse but the offshore tech support is more like tech stonewalling at a certain point. Ya just gotta figure a way around it or them or who ever ..... lottsa luck !!!
JimBob
"Master of the Sr.Moment"JimBo_0313
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Posted March 18th, 2005 19:00
Hummm ,
My 4700 is a 3.4 / P4 and was supplied with the small heat sink originally ( some references indicate a major Intel/Dell faux pas ). The heat sink I got today is the big one like yours and it fixed my problem. The one difference I've noted in the fixed vs. the still drives me *&@!%&%$ crazy ( 4700's and 8400's ) is that the CPU was replaced in addition to the heat sink ( as in my case ). I wonder if the CPU might be the final piece to the fix !!! Then again I might not have a clue what I'm talking about .... but somewhere deep in the eroding recesses of my mind a little voice says that the dang fans had little to do with the problem from the gitgo !!!!
JimBob
"Master of the Sr. Moment"Dave, what Bios version are you using? ao4 seemed to help a little. The longer my system stays on the quieter it gets, or i just get use to it. I tried to get dell to send a nidec fan but kept getting delta replacements. The last had a different revision number and is much quieter than the other three. Plus make sure that the thermal grease it applied to the processor proper! Not too much, i used antec silver #5 seems to work better than oe. with antec silver#5 a little goes a long way they suggest a drop no larger that a grain of rice for the p4.
dimension 8400
3gig p4, 512mem
xp home
dvd/rw,dvdrw
ati pci300
RoHe
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Posted March 17th, 2005 17:00
Maybe this is a stretch, but here goes. When I open front cover on my normally quiet 8400, temp of HD drops by about 2 degrees according to app running in background, suggesting better airflow. USB cable without iPod shouldn't be recognized as a USB device and shouldn't draw any power from the port. So perhaps it's really a mechanical thing. Either the cable is preventing something from vibrating, or it changes the airflow slightly so the fan temp sensor is cooler and happy. Temps may be at edge of sensor's on/off set point, which is suggested by whining fan. It starts to rev up and that cools sensor just enough to slow it down. So a slight change in airflow from the cable might be all it takes.
Either way, be glad you found a simple solution. :)
Be interesting to see if this solves the problem on anyone else's system. And interesting to hear what some Dell engineering type has to say.
Ron
Message Edited by RoHe on 03-17-2005 11:46 AM