FT-891 problems

Discussion in 'General Technical Questions and Answers' started by W9LEF, Jan 23, 2021.

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  1. W9LEF

    W9LEF XML Subscriber QRZ Page

    My Yaesu 891 has been a great radio until now.

    What's happening is when I key the mic to initiate a transmission, the radio reboots. This seems to happen once I've used the rig for a bit (total tx time about 5-10 minutes or so). Max 100 watts, SWR is 1.5 or less and a brand new feed line R8X.

    The rebooting happens whether I'm using a mic or using it with digital modes i.e. CAT control.

    Has anyone else experienced this issue and if so, how did you resolve it short of purchasing a new radio.

  2. KK4CUL

    KK4CUL Ham Member QRZ Page

    Sounds overly simplistic, but my guess is a not-so-great connection in your power cable between PSU and radio. That could be improperly crimped PowerPole connectors, terminal lugs on the PSU, even the inline fuses in the power cable (big one on a few of the Icoms I've owned). And since you said after a while, my guess is if it IS a weak connection their might be heat involved causing something to expand or contract, or even a fan is kicking on just barely drawing over the required current or voltage?

    Wouldn't hurt to disconnect the cable at both the radio and PSU ends, clean and secure the contacts or adapters at every step and make sure there's no corrosion or oxidation on any inline fuses.
    KA9TQC likes this.
  3. W9LEF

    W9LEF XML Subscriber QRZ Page

    Thanks for the suggestions. I'll check it out.
  4. W1NB

    W1NB XML Subscriber QRZ Page

    A couple thoughts:

    1) given it happens after you’ve transmitted for a few minutes, it may be heat related. Check to see if the fan is coming on and that it’s not blocked.

    2) it’s possible RF is getting into one of the external connections. Try removing everything except the mic, power and antenna and transmit at 25 watts for some length of time to see if the problem still happens.

    3) make sure the power supply is adequate. It may be that you are drawing close to the maximum amperage for the supply. After you’ve transmitted for a period and the radio increases in temperature it may be drawing a bit more current that exceeds your supply’s capability so it briefly shuts down.
    KA9TQC likes this.
  5. KA9TQC

    KA9TQC Ham Member QRZ Page

    I found this exact behavior trying to use a Honda eu2000 generator's d c output. Switching to truck battery solved it. The generator instructions said "battery charging only"
  6. KD0RCB

    KD0RCB Ham Member QRZ Page

    Good suggestions, and also if you have a dummy load , try transmitting into that at various power levels, and see what happens..that would fully eliminate the antenna system, and coax to antenna...
    W4NNF likes this.
  7. KA2TVX

    KA2TVX Ham Member QRZ Page

    You said "brand new feed line R8x" .
    Has this only started happening since installation of the new feed line?

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