YAESU FT-107M DISPLAY UNSTABLE

Discussion in 'Radio Circuits, Repair & Performance' started by KE7TZ, Apr 16, 2019 at 5:32 AM.

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  1. KE7TZ

    KE7TZ Ham Member QRZ Page

    DISPLAY WAS ON 3.937.0 AFTER ABT 15 MINUTES LAST TWO DIGITS BOUNCE UP MAINLY DOWN AFTER ABOUT 45 MINUTES FREQ R/O IS 3.933.0+/- RX/TX IS 3.937.0
    ALL DIGITS GOOD. IDEAS? MAYBE CAP ON DISPLAY BOARD???
     
  2. G4COE

    G4COE Ham Member QRZ Page

    Whoooa, hang on, what IS bouncing, the VFO or the display? Better check the RX and TX signals first, go fiddling with the display and 'IF' it's the VFO then you are going to get no where so lets determine this first since you did not mention this.

    A service manual would be useful here, try this http://www.radiomanual.info/schemi/YAESU_HF/FT-107M_serv.pdf

    Dave
     
  3. N8YX

    N8YX Ham Member QRZ Page

    Counter chip (an LSI part) likely going bad.

    JA2SVZ came up with a replacement using a PIC on a custom carrier board. I'd replace all electrolytics and tantalums on the Counter Assembly Unit as a first-pass effort but if that doesn't cure the issue you'll need to replace the chip.

    http://fpga.world.coocan.jp/COUNTER_e/index.html
     
    Last edited: Apr 16, 2019 at 3:35 PM
  4. KE7TZ

    KE7TZ Ham Member QRZ Page

    THE RX/TX IS GOOD...STAYS ON FREQ 3.937.0 JUST THE DISPLAY ISN'T STABLE
     

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