FT-991A Audio Feed-back Through Speaker

Discussion in 'General Technical Questions and Answers' started by K8TMW, Dec 22, 2019.

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  1. K8TMW

    K8TMW Ham Member QRZ Page

    My 6 month old FT-991A just started generating serious feedback through the speaker when the microphone is keyed. The antenna is fine, less than 1.2 on 40M, where I was working. Coax is good. Ground is good. It will do it with the power down to 5W.

    I can't say exactly when it started. I've been mostly listening recently. The only thing I did different was trying to use the USB and RS-232 interfaces with Ham Radio Deluxe to receive data. Everything is now disconnected.

    Any advice would be appreciated.
  2. K7TRF

    K7TRF Premium Subscriber QRZ Page

    Is this coming through the rig's speaker or an external speaker and if external is it a set of active speakers requiring power? Does this happen when you transmit into a dummy load?

    You can have a low SWR on an antenna and still have substantial common mode RF currents on the coax shield on some bands that can lead to RFI problems in the shack. What kind of antenna is it? Do you see the same problem if you reduce your transmit power?

    And I guess the other obvious question is whether you could have accidentally turned on your Monitor function which of course should only be used when you run headphones. (page 72 of the manual)
    K8TMW, PY2RAF and KU3X like this.
  3. K8TMW

    K8TMW Ham Member QRZ Page

    See, this is why I love amateur radio so much: there are lot's of good people willing to help the newbies. The monitor function was turned on. Can't say when or why. Thanks for the super quick help!!!!!
    WA3GWK and K7TRF like this.
  4. KE0EYJ

    KE0EYJ Ham Member QRZ Page

    Oh, just saw your reply... good for fixing it!
    K8TMW likes this.
  5. K8TMW

    K8TMW Ham Member QRZ Page

    Thanks for the input! I'm just glad it was a simple, if not embarrassing, fix. ;-)
  6. PY2RAF

    PY2RAF XML Subscriber QRZ Page

    Hi Tim,

    As a digression on the thread; shortly after I got my FT-991A, I was panicked because I had a "stuck s-meter".

    Called a few friends, a respected tech about my issue and no one had idea of what was happening.

    I filed a support ticked with Yaesu, freaked out, with the following video as supporting evidence in order to help the troubleshooting: https://rf3.org:8443/q/stuck-smeter.mov

    Well, guess what was it: Notice the "RF Gain" pot position at the beginning of the video :p

    Merry Christmas and happy 2020 everyone!!! \o/ <3
    K8TMW likes this.
  7. WQ2H

    WQ2H QRZ Lifetime Member #214 Platinum Subscriber Life Member QRZ Page

    I love Yaesu - but their instruction manuals do take time to "thoroughly digest".

    I've had a 991 since they introduced it and I still learn something new about it just about every week. :) Good luck !

    Jim, WQ2H / WK2XAH
    K8TMW likes this.

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