One of my computer fans is working backwards

Discussion in 'General Hardware' started by Lunarbob, Mar 4, 2015.

  1. Lunarbob

    Lunarbob Guest

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    I have an odd problem here, it seems that one of the fans in my computer case is working the opposite that it should be. The fan on the top of the case that blows the hot air out is slowing down as the temperature rises and speeding up as it lowers.

    Currently Speedfan tells me its running at 3190RPM while my cpu is 38C.
    Earlier I was playing a game of Shadow Warrior on steam, the cpu was 43C, but the fan speed dropped to 2935RPM. I wouldn't really mind too much except that around that speed it started to rattle making an annoying noise.

    Has anyone some experience in such a problem? Or advice please? Thank you.
     
  2. Hootmon

    Hootmon Guest

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    Do you have more fans blowing out compared to in? A stronger fan might be giving you an negative internal pressure. Opening the case will demonstrate this.

    Generally you want to be running positive pressure with filtered intakes.
     
  3. Lunarbob

    Lunarbob Guest

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    Do you have an idea how I can check that?

    I have a cpu fan thats been running at 3100-3300 consistently, I believe that one is the one on the actual processors.

    I have a fan on the bottom of the front that blows air out, and that keeps around 1400-1430.
     
  4. Hootmon

    Hootmon Guest

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    Take the side panel off. If the top fan starts spinning the right way you know that too much negative pressure is the problem.


    Any intake fans?
     

  5. jbmcmillan

    jbmcmillan Guest

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    Always had my front/side fans inward and back/top out seems to work best for me.
     
  6. Lunarbob

    Lunarbob Guest

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    Wait, my mistake. My Front bottom fan actually brings the air in.
     
  7. dk_lightning

    dk_lightning Ancient Guru

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    He is not saying his fan is spinning backwards. Please go back and read the thread and not just the title..
     
  8. Hootmon

    Hootmon Guest

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    I understand that. Its just a matter of degree.

    The same trouble-shooting applies if his other fans spin up when temps rise they could slow down a weak fan.

    All he really needs to do to prove it is remove the side panel. If the problem goes away its a pressure problem. It it persists, its an electrical problem.
     
    Last edited: Mar 6, 2015
  9. Hootmon

    Hootmon Guest

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    So, front bottom intake. Top exhaust. What else?

    Is your PS drawing air from the inside or outside of the case?
     
  10. Lunarbob

    Lunarbob Guest

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    Sorry for such a late responding.

    I disabled one of my fans today, the top back fan was an exhaust fan. It was running at a maximum of 1450, but started to drop rapidly, it was around 900 when I unplugged it since it was making a noise.

    Now my fans situation is

    Front bottom I have an intake fan, and that is the one that has been working in reverse. It is hanging around 3000RPM while I am web surfing, but when a game starts and more heat starts generating it will start to lower speed instead of raise it.

    I have the cpu fan which is working the right way, hanging around 3100 now, but if the temp gets close to 50C it goes faster, I had around 3500 earlier testing it.

    My only other fan is on the GPU, it works fine as well.

    The fan on the PSU isn't listed anywhere, but it blows upwards.

    Apparently I need to buy some replacement fans because I now have two exhaust fans that don't run. On the top back and the very top.

    I read that the positive/negative airflow doesn't actually happen if your case isn't sealed up. Mine has a fairly large grated area on the side.
     

  11. allesclar

    allesclar Ancient Guru

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    Swap the fan out with another one and see if the same scenario is reproduced :)
     
  12. Lunarbob

    Lunarbob Guest

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    I am thinking of buying some 4 pin fans so I can control their speed, but I'm not sure if my motherboard has connections for them. I have looked at the board and the specs but I still can't tell. Would you be able to tell me where in the specs I should be looking for this information? Thank you.

    General
    CPU - Support for Socket AM3 processors: AMD Phenom™ II X6 / X4 / X3 / X2 (except 920 / 940) / Athlon II X4 / X3 / X2 / Sempron processors
    - Supports CPU up to 140W
    - Supports AMD OverDrive™ with ACC feature (Advanced Clock Calibration)
    - AMD LIVE!™ Ready
    - Supports AMD's Cool 'n' Quiet Technology
    - FSB 2600 MHz (5.2 GT/s)
    - Supports Untied Overclocking Technology
    - Supports Hyper-Transport 3.0 (HT 3.0) Technology
    Chipset - Northbridge: AMD 770
    - Southbridge: AMD SB710
    Memory - Dual Channel DDR3 memory technology
    - 4 x DDR3 DIMM slots
    - Supports DDR3 1600(OC)/1333/1066/800 non-ECC, un-buffered memory
    - Max. capacity of system memory: 16GB*

    *Due to the operating system limitation, the actual memory size may be less than 4GB for the reservation for system usage under Windows® 32-bit OS. For Windows® 64-bit OS with 64-bit CPU, there is no such limitation.
    BIOS - 8Mb AMI BIOS
    - AMI Legal BIOS
    - Supports "Plug and Play"
    - ACPI 1.1 Compliance Wake Up Events
    - Supports jumperfree
    - SMBIOS 2.3.1 Support
    - CPU, VCCM Voltage Multi-adjustment
    - Supports Smart BIOS
    Audio, Video and Networking
    Graphics - n/a
    Audio - 7.1 CH Windows® Vista™ Premium Level HD Audio (VIA® VT1708S Audio Codec)
    LAN - PCIE x1 Gigabit LAN 10/100/1000 Mb/s
    - Realtek RTL8111DL
    - Supports Wake-On-LAN
    - Supports PXE
    Expansion / Connectivity
    Slots - 2 x PCI Express 2.0 x16 slots (green @ x16 mode, orange @ x4 mode)
    - 1 x PCI Express 2.0 x1 slot
    - 3 x PCI slots
    - Supports ATI™ CrossFireX™
    Connector - 4 x SATA2 3.0 Gb/s connectors, support RAID (RAID 0, RAID 1, RAID 10 and JBOD), NCQ, AHCI and Hot Plug functions
    - 1 x ATA133 IDE connector (supports 2 x IDE devices)
    - 1 x Floppy connector
    - 1 x IR header
    - 1 x COM port header
    - 1 x HDMI_SPDIF header
    - CPU/Chassis/Power FAN connector
    - 24 pin ATX power connector
    - 8 pin 12V power connector
    - CD in header
    - Front panel audio connector
    - 3 x USB 2.0 headers (support 6 USB 2.0 ports)
    Rear Panel I/O I/O Panel
    - 1 x PS/2 Mouse Port
    - 1 x PS/2 Keyboard Port
    - 1 x Coaxial SPDIF Out Port
    - 1 x Optical SPDIF Out Port
    - 4 x Ready-to-Use USB 2.0 Ports
    - 2 x Powered eSATA2/USB Connectors
    - 1 x RJ-45 LAN Port with LED (ACT/LINK LED and SPEED LED)
    - HD Audio Jack: Side Speaker / Rear Speaker / Central / Bass / Line in / Front Speaker / Microphone
    Other Features / Miscellaneous
    Unique Feature - ASRock OC Tuner
    - Intelligent Energy Saver
    - Instant Boot
    - ASRock Instant Flash
    - Hybrid Booster:
    - CPU Frequency Stepless Control
    - ASRock U-COP
    - Boot Failure Guard (B.F.G.)
    Support CD - Drivers, Utilities, AntiVirus Software (Trial Version), AMD OverDrive™ Utility
    Accessories - Quick Installation Guide, Support CD, I/O Shield
    - ATA 133 Cable
    - 2 x SATA Data Cables
    Hardware Monitor - CPU Temperature Sensing
    - Chassis Temperature Sensing
    - CPU/Chassis/Power Fan Tachometer
    - CPU Quiet Fan
    - Voltage Monitoring: +12V, +5V, +3.3V, Vcore
    Form Factor - ATX Form Factor: 12.0-in x 8.2-in, 30.5 cm x 20.8 cm
    OS - Microsoft® Windows® 7 / 7 64-bit / Vista™ / Vista™ 64-bit / XP / XP Media Center / XP 64-bit compliant
    Certifications - FCC, CE, WHQL
    - EuP Ready (EuP ready power supply is required)
     

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