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Thread: Power Supply or Airflow Problem

  1. #1
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    Power Supply or Airflow Problem

    I recently put a Creative Sound Blaster 5.1 card in my computer (the one at newegg for $33). My fans now make more noise and the rpms seem to drop and the fan gets louder when the computer is doing more work. I took the side cover off so I could see which fan was making noise and the new noise stopped. There was just normal fan noise and it didn't go up and down depending on how much processing was going on. The sound card is fairly large but it does not seem to block any airflow. I put the cover back on and the noise started again. It does seem to be the cover rattling that is making the noise but it rattles worse when the computer is doing more work. I only have a 300 watt PS. I'm not sure what brand but the guy who put it in said it was a fairly good one (not bottom of the line anyway). I checked and no wires etc seem to be near fans or restricting rotation. I am assuming that with the cover on it is somewhat more work for the fan to pull air through the case. Is it possible that a subtle change in airflow and/or the extra power consumed by the sound card is too much for my power supply and thats the reason for the fan/rattle problem which appears and disppears when the cover is on or off. I had taken the cover off and on numerous times before installing the card and it never seemed to rattle even when put on incorrectly.

    The system info is Athlon 1700+, Biostar M7VKQ-A003 Ver 1.1 mainboard, there is one case fan, one PS fan and one CPU fan, Sony DVD, ATAPI CD-RW, 40GB WD HDD, Cisco wireless DSL board, Maxtor 40GB USB external HDD, Canon Scanner with USB connection, Logitech USB mouse, HP printer with USB connection, Palm Hotsync cradle, Belkin powered USB hub, Zio! USB card reader. (not using everything at once!)

    Running XP home
    Last edited by drdan; 01-29-2003 at 10:02 PM.

  2. #2
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    It could be a subtle change from putting the sound card in if it is tight in there already. Have you checked temps to see if there is any change in that? For the cover, a small piece of insulation could probably stop the rattle, but I would cofirm that the temps are ok before eliminating the symptom.

    Your power supply could be strained, but I don't think you would hear that through extra vibration, you would see weird shutdowns and screen freezes.

    Budfred

  3. #3
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    To confirm temps do I run the computer for a while and then restart to troublshooting screen? How much will it cool off during the 3 minute statr up procedure. Any ideas on why fan rpm lowers and rattle seems to change with processor load. I would think if the processor is doing more work the fan rpm if anything would go up.

  4. #4
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    What's confusing is the problem didn't happen with the cover off.

    In one way it sounds like a rattle. In another, it sounds like the CPU fan might be getting weak or worn. Actually weak is less likely than a worn bearing that, under more load, doesn't rattle but more like buzzes and causes the RPM's to lessen due to increased resistance to spinning in an orbital pattern of the spindle.

    But then you didn't mention your power supply size either. How many of these peripherals load at startup? The Sounblaster just may be putting the ability of the PSU to the limits as it seems it is busy enough already. What device will suffer first is anybodies' guess when on the borderline of what the PSU can deliver.

    I would try removing the case again and going through several motions to try the repeat of the problem in an attempt to pinpoint it.

    Have you looked in BIOS to see the CPU fan speed and CPU temp?

    Edit: Oops 'cover' not 'case'. Side panel? Or full cover?
    Last edited by Fruss Tray Ted; 01-30-2003 at 08:09 PM.
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  5. #5
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    I would check temps in BIOS after running for a while. You Restart and immediately go into BIOS when the opening screen comes up. It won't have a lot of time to cool down before then. If you mobo can monitor temps, there will be a BIOS option for PC Monitoring or Health or something like that. You could also download MBM5 or another temp monitoring program, but the BIOS is probably the most reliable reading.

    Budfred

  6. #6
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    Yeah, I think I'd go with MBM5 if your system has the sensors. You can monitor individual fan speeds on the fan tachs as well as temps if you're equipped...

    Are any of your fans "smart" fans able to throttle up or down as called upon?

    If so, with the cover off and perhaps running cooler they're not throttling up...

    Reminds me of a car I once had where at 57Mph I'd get a vibration...not less, not more...just a 57!
    Lighten up! --- A merry heart does good like a medicine. (Proverbs 17:22)

  7. #7
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    The problem has changed some. Now the fan makes noise and rattles the case only when cold. When I start the computer when it has cooled off overnight the fan shakes, roars and rattles until the computer warms up, maybe 3-5 minutes after startup. I have MBM5 and the CPU is running 61-62C under load and the CPU fan is about 5900 rpm. The CPU fan is the only fan speed I'm getting and the speed doesn't change when the noise is occurring so I assume the problem is the case or PS fan. I would think it was just a bad fan if the problem did not suddenly start after installing the sound card.

    Any more thoughts on this?

  8. #8
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    If I went to a better power supply, would the Antec True power 330 watt likely be sufficient. How hard would this be to replace and any potential problems?

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    The Antec True Power are reported to be quite good, but it might be worth a few extra bucks to get the next level just to be sure you don't run into trouble. It is very easy to replace the power supply. Disconnect the power connections, remove four screws and slide it out. Slide the new one in, replace the screws and connect the power plugs. You may want to have a plastic tie handy since you will probably have some power plugs that you won't need and can tie off to keep out of the way.

    For the fan issue. I would check to make sure case fans are screws properly in place since one could simply be loose. If one is, you can also remove it and put some washers on, then remount if you want it to be significantly quieter. If you do have a bad one, you can replace it easily. I would boot up cold with the case open to find out where the rattle is coming from.

    Edit:

    Your CPU is running a bit hot and it may be worthwhile to look at upgrading your heatsink and CPU fan. That is assuming that the heatsink is well seated on the CPU, if it is not, reseating with Arctic Silver might fix it.
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  10. #10
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    I'm wondering if the problem might be the fan itself. It could be that when the fan cools down friction becomes an issue and as it warms up it spins freely and the sound goes away....

    I would agree with Budfred that your temps are a bit high. Did you affix the headsink yourself? It would appear from the temps that indeed something's not happening as it should at the interface of the sink and processor.

    Heatsink and fan combos are relatively inexpensive... Well, unless you want to get a bit sophisticated...Thermaltake Volcano stuff etc.

    Perhaps the fan noise is just a precursor to its failure....
    Lighten up! --- A merry heart does good like a medicine. (Proverbs 17:22)

  11. #11
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    Logical answers and I appreciate the info. I now have some avenues to explore. I'm thinking I need to check or replace the CPU fan and heatsink whether it's related to the noise or not. That seems fairly easy unless the the heatsink is currently stuck to the CPU. Isn't there some kind of tape or something that "melts" to the CPU the first time it heats up? If so, how do I get the heatsink off and clean up the CPU?

    I think I will explore tightning up or reseating fan and sound card screws first. I may just replace the fan anyway since they're cheap.

    There is still the basic question though. Since the fan does not make noise (even when started cold) with the cover off, what is going on? My three theories are:

    1. The cover changes something about the seating of the fan or position something else and it causes a rattle. This is the least likely since that probably wouldn't change much when the computer warms up - but it might.

    2. The sound card has changed the airflow enough that a hidden problem with a fan or fan bearing shows up because it's slightly more a strain to pull air through with the cover off. In other words an airflow problem. This could contribute to the higher CPU temps I would think. Once the fan heats up it's easier to turn and the problem is masked again.

    3. The change in airflow does increase strain a little but it is really showing a problem with power supply rather than fan bearings and that's why, when it first started, the fan speed seemed to change in relation to the amount of work the computer was doing. Still it seems that most power supply problems cause different symptoms than this so it's less likely than the fan/airflow theory.

    Actually I guess it could be a combination of two or all three.

    This is not a real significant problem but it's fun for me trying to figure it out. I may very well solve the noise issue by replacing a fan but it may still be that I'm "on the edge" in terms of power supply or I may need to address case airflow issues. I don't want to put a bandaid on what could be a significant underlying problem for the future.

  12. #12
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    It should be pretty easy to remove the CPU heatsink. It usually will have a piece of thermal tape, pad or grease, but this should be glued to the CPU. Putting the new one on is just a bit more tricky. I recommend using Arctic Silver because it is highly thought of around here and it is supposed to drop the temp another 5 degrees or so. There are detailed instructions on their website about how to use it and I would recommend following them. I printed them out so I would have them handy as I was working. To get the Arctic Silver thin and smooth on the CPU plate, I put postit notes forming a square around the contact plate on the CPU so that the edges would be clean and that worked well.

    For the fan noise..... If it is not making the noise with the cover off, I would suspect that it could be a cable or something banging against the fan blades, although that doesn't explain why it goes away after a while. I doubt it is due to air flow or bad bearings and suspect it is just something loose.
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  13. #13
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    Is it possible to remove the Soundblaster to monitor the temps at least for one reading?

    Are your fans and heatsinks blown free of dust? Is there possibly a corner screw missing which attaches your motherboard to the case side or something similar like missing CDROM mounting screws etc.? I would eliminate any physical rattling with rubber bands, cable ties, matchbooks, popsicle sticks and clothespins or even putting a slight stress on the case with palm pressure to see if it stops.

    If it is positively one of the fans, you could momentarily (for an instant) hold or slow the fan speed with your finger to find which one causes the rattle. Then replace once you know. I realise it's going to be difficult to isolate due to it's limited time window (warm up) and lack of problem with the cover off. Hmmm, let's see,,, if you make an audio recording of it and send it to someone they might say "Oh yeah, I know what that is..." "It's the doomahicky by the thingamajig causing an inverse stress ont the whatchamacallit!

    The heatsink pad used between the CPU and heatsink is more like an adhesive tape with an absorbent back on it. The tape is non-drying like celophane type 'Scotch Tape' (where's the registered trademark when you need one? ). The backside has a grease like compound applied to it (consistency like hand cream) that dries over time but is not supposed to. If the pc is more than a few years old (or has many hours on it) it would be a good idea, esp. if you are experiencing elevated temps over time, to re-apply some heatsink compound.
    ________________________________
    Edit:
    The more I think of it, it seems to be the CPU fan is the likely culprit and to hold the fan back on an already high temp condidion wouldn't be a good idea. Replacing the HS/fan combo with some fresh grease would be a real easy, inexpensive try if not cure to "The case with the Mysterious Rattle" /Edit
    Last edited by Fruss Tray Ted; 02-08-2003 at 03:07 PM.
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  14. #14
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    If you decide you are going to replace the heatsink and fan I would suggest doing things up right and lapping the new heatsink...

    61C is actually a bit on the high side. Since the RPMs appear to be within acceptable limits it certainly focuses in on the interface.
    Lighten up! --- A merry heart does good like a medicine. (Proverbs 17:22)

  15. #15
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    Well, some more info but no clearer (at least for me) I took the cover off and started it cold and no noise (as before). However, after 2 or 3 minutes I opened MBM5 to check the temp. As soon as I clicked on it the sound in the computer changed. There was a slight "growling" coming from one of the fans. I know it sounds ridiculous with the cover off but I still couldn't tell which one it is. Without studying the contact point with the blades still, I was hesitant to touch the blades themselves and putting pressure on the side of the fans did not change the sound. Maybe the PS fan as I can't touch it at all. I tried some other applications and increased load would change the sound also with those.

    But - once the computer had been running for about 15 minutes, increased load did NOT change the sound anymore. BTW the CPU temp stayed at 56-57C with the side cover off.

    Anyone have an "AH HA!" moment yet?

    I'm starting to get more interested in what's really going on than in just getting it running quietly again.

  16. #16
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    If you can, with the cover off, after it starts making noise, disconnect the power from one fan at a time until you find the one making the noise. Be sure to reconnect each fan before moving on to the next one. Be careful not to touch any boards, and wear an antistatic strap while doing this. After you find the noisy fan, turn the system off and replace it. Replacement fans are inexpensive, I just ordered one from Directron for my wifes computer - cost- $1.
    Also I'm not sure how the fan speed is monitored, but if it is calculated based on current draw, and the bearings are going bad,the draw could increase, The sensor would think that the fan speed increased, but it would have actually slowed down.

    Directron

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    2 things occur to me:

    1. If the sound changes after the warm up, chances are good that it is the CPU fan since that it the only fan that is directly exposed to rapidly rising temps.

    2. If the temp is lower with the case off, it suggests that you probably don't have enough air moving through the case and another fan or higher CFM fan might be worthwhile.
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  18. #18
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    Is it possible...

    ...that the sound is coming from the hard-drive? When you say 'growling' and associate it's stabilizing after a few/several minutes it may be that. At least I have seen a drive do that type of sound before. And you mention the sound when the pc is 'under load'.

    An old mechanics trick to finding noises that are hard to find by ear is to use a stick (nowadays a type of stethoscope can be purchased) to pinpoint the source or area of the sound. This is real good at finding which cylinder has noisy valves. It makes me wonder if you could use something similar to listen for the sound in your pc. Maybe a dowel or even a tree branch of approximately 1/2" to 3/4" dia. about a foot to foot and a half long should do. You place one end on the item you want to test and put the other just in front of your ear closing the ear opening with the little flap (Tragus) in front of it with the dowel. You may think it sounds funny but it works like a charm at finding low frequency noises.
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  19. #19
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    I don't think it's a good idea to unplug and plug fans in while the system is powered up. Too many bad things could happen.

    It's simple enough to unplug the case fan before you power up. See if that makes a difference. But, do not unplug the CPU fan!

    Have you checked the mounting screws for the PSU to make sure they are tight? Are all your drives secured tightly?

    I agree wholeheartedly that the HSF should be replaced. I assume you're using the HSF that came with the CPU?

    An extremely good and inexpensive heatsink right now is the Thermalright SK-7. Use an 80mm case fan of your choice with it. I would recommend a fan with minimal cfms of 40 or more. Bestbyte has some good 41cfm Top Motor fans for dirt cheap. Or, you could go with a 47cfm Panaflo UA1 or the 53cfm Mechatronics.

    Your CPU temps shouldn't be that high for a stock AXP 1700+. When you replace the heatsink, get yourself some Goof Off found at Walmart for cleaning off the old TIM from the core. Then follow that up with some 91% isopropyl alcohol for a final cleaning. Use a coffee filter or other lint free cloth to give it that final wipe before applying ASIII.
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  20. #20
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    I would agree with BB regarding unplugging/plugging fans...we don't know how "fragile" the components are that either monitor or connect to them. I think it runs too close a parallel to "hot swapping" devices not intended to do so.

    And, for sure the Heatsink Fan...which unplugged on most won't allow a boot to begin with...a cheap replacement fan could provide the necessary troubleshooting information rather than result in shelling out for a new MotherBoard!
    Lighten up! --- A merry heart does good like a medicine. (Proverbs 17:22)

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    At this point, what I want to know the most is why does increased load change fan speed. It is not hard drive noise as Fred suggested. I'm sure that with more attention or using a listening device I could pinpopint the fan without much problem. I'm thinking of replacing the PS first just to see, though. If there is some kind of marginal power supply problem then I don't want to mask it with a better fan. I may build a better computer within the year and I assume an Antec True Power 380 or 430 watt would easily transfer to a new computer and still be in good shape.

    Before I go that route, can anyone think of any other reason that the computer doing increased work would change fan noise. The CPU temperature does not rise noticeably when the fan noise increases. Also the CPU fan speed on MBM5 does not change when fan noise changes. I do not believe the computer has any features to change fan speed. The only thing I can think of is a power drain which is just enough to affect a fan that probably has some problems anyway. But I don't know enough to determine if there is some more likely explanation.

  22. #22
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    I'm shooting from the hip here...but doesn't MBM5 offer monitoring of voltages on all the legs? I'm also wondering if these have alarms you could set to let you know their values might have changed...

    Sorry I've not done the research for ya...
    Lighten up! --- A merry heart does good like a medicine. (Proverbs 17:22)

  23. #23
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    Now see, I told you I didn't know enough to think of some things. That makes sense to the point of being painfully obvious. Instead of alarms I can just pull up the "dashboard" and watch all the voltages to see if any of them change when the sound changes. If I can GET the sound to change then, it's finicky. Anything more specific I'm looking for? In reading reviews of power supplies, one of the problems with cheaper ones is keeping voltages constant even when there is enough overall power. Perhaps something like that is going on. That might account for this weirdness without the typical symptoms of not enough power.

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    Budfred ..... Caveat Emptor....

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  25. #25
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    Okay, I'm sure you're getting tired of this but a little more info again. Today I started the computer up with the side cover off, after it sat for two days. There was no noise whatsoever, even under load. Then after being on for an hour and a half and heated up it started making noise under load again! LOL

    I did pinpoint the noise to the PS fan I believe. I put my hand over the exhaust holes for the PS and the noise instantly got very loud and the whole power supply started shaking. I was only blocking the exhaust about 70%, I didn't seal it.

    Also, I noticed that at one point the reading on the +12V meter went from +12.11 to +32.18 and then back down to +12.00. I don't know if that's a misreading with MBM5 but it's another clue that I may have a screwy PS. Just the PS fan acting funny I think is enough to try replacing the PS first, then the CPU fan and heatsink. I currently have a Premier 300 watt PS made by ATNG which I just had installed a couple of months ago.

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