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Yaesu 857 cooling fan always on?

Discussion in 'General Technical Questions and Answers' started by K1IGS, Oct 13, 2018.

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  1. K1IGS

    K1IGS Ham Member QRZ Page

    Hey folks, I fired up my 857 this morning and the cooling fan started running continuously. It's not the fan that comes on when I transmit - that one seems normal. This one sounds smaller. It's definitely not temperature related as it started doing this immediately when the radio was still stone cold.

    Any ideas?
  2. KA9JLM

    KA9JLM Ham Member QRZ Page

    What is the ambient temperature ?

    Power supply voltage ?
  3. K1IGS

    K1IGS Ham Member QRZ Page

    It's probably 55 degrees in my shop when I get in there in the morning. 13.8 to 14 volts from my power supply.
  4. WD8BWW

    WD8BWW XML Subscriber QRZ Page

    857 has two fans that run when the radio is transmitting or very hot. "It's not the fan that comes on when I transmit - that one seems normal." The design is such that both fans are in parallel so it is not possible for only one to run. upload_2018-10-14_13-13-35.png
    KA9JLM and K1IGS like this.
  5. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    Did you try putting a matchstick into the blades or something to confirm one is running and the other one is not?

    Seems almost impossible unless one fan has failed entirely, since they both run together.
  6. K1IGS

    K1IGS Ham Member QRZ Page

    Ya, you're absolutely correct - they're both running. I pulled the faceplate off and was able to take a look. Sure enough, they're both running. The fan sound increases when I transmit, then settles down again when I release my PTT.

    Also checked my power supply to verify - 14.07 volts on my multimeter.

    Radio is cool as a cucumber. Hmm.
  7. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Are the fans dirty?
  8. K1IGS

    K1IGS Ham Member QRZ Page

    No, pretty clean. I also put some compressed air through the radio just in case but nothing really came out. The radio is only about 8 months old.
  9. AA7QQ

    AA7QQ Ham Member QRZ Page

    Is there something in the settings that may have constant cooling for heavy digi use?
    I know the schematic well & other than a cap going bad to GND, I cannot think of anything but settings, with your symptoms.

  10. WB2WIK

    WB2WIK Premium Subscriber QRZ Page

    "Cut the red wire.":):p

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