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Yaesu FT-301AD display mod [message #45] Fri, 31 March 2006 23:36 Go to next message
root is currently offline  root
Messages: 208
Registered: December 2004
Senior Member

This is for the FT-301 series radios with the pesky digital display.

The original display runs very hot. It burns segments out then after a while you have no display, There are no TIL306 and TIL308 segments to be found and no way to know where your at on the band.

This is to help the sorry folk's with a decent radio and no display.

The analog FT-301 has a different front bezel so the internal installation may not work for you. IF you intend to have the display external (easier) go to the wiring instructions and run the cables to RCA jacks or BNC's on rear panel. This is how I did it, Looks factory and works way better than original.

Internal installation (difficult)
  • Remove top cover with the 4 plastic pull knobs

  • Remove the 12 screws on the bottom cover

  • Remove all knobs on the front panel and the 8 counter sunk screws from front panel trim ring.

  • Pull the front panel gently and cut resistor and wires off the calibrate control (save the Cal knob to keep the hole plugged)

  • Remove the Display logic unit PB-1524B and remove the jack nut and old mounting bracket for the board off the front of the VFO, find more compact slim line screws to put back into the VFO for more clearance for the new display board. (Junked CB case screws are a good source)

  • Remove the Display premix unit PB-1541D (bottom of chbassis) and cut the 3 wires at the rear, The white is the VFO feed, cut short and heat shrink. The orange wire is +5V cut this short and heat shrink also.
    The brown wire is the +13.8V source, keep this to hook up the new display power to.
    Remove the silver braid off the ground lug, The ground lug is where the back wire will go to on the new display board.

  • Unplug the black header plug that runs to the band switch. I kept this intact for maybe band data, etc., every position of the band switch grounds one wire at a time.
    On the front panel remove the bezel, remove the 3 small post holding on the tinted lens, file these smooth. I had to discard the tin box for the VFO/CLAR/FIX lights ,I'd rather have a display that works then lights telling me this as well as the switches.

  • Remove the wires off the tin box and heat shrink them. Save the VFO/CLAR/FIX lens to put back on to plug the hole up (I used the JB-weld to glue it back on)

  • Trim 1/8" of plastic off the right hand side of the face plate (not the bezel)

  • Trim 1/16th" off the left hand side of the face plate this will trim one side of the plastic box off also.

  • Trim 1/4" of sheet metal off the chbassis on the right hand side behind where the face plate goes.

  • All this trimming clears the new display board and the display screen. Take your time it will look nice.
    Put face plate and plastic bezel back together with the 3 screws, The top screw needs to be replaced with one with a smaller head.

  • Disbassemble the new display screen by carefully twisting the tabs back into place, GENTLY pull the metal bezel off the screen and circuit board.
    I used JB-Weld to mount the metal bezel to the FT-301 face plate & back of the FT-301 plastic bezel (on the back). It worked well and is way strong. If you don't glob on a mess of it, you'll have a clean and durable mount made up.
    Remember this will also hold both of the new display circuit boards.

  • Carefully reinstall the display screen and the board (make sure it's right side up!) Gently twist the tabs back, I checked it with the 9 V battery to make sure the display was lined up properly with the circuit board.

  • Now solder your RG-174 cables on the new display board mark one cable so you know where it goes, and cut off the 9 V battery connector close to the end of the wires.

  • Put some double sided sticky tape on the front of the VFO casing to help hold and insulate the display board.

  • Mount your faceplate and check for interference with the display board with the chbassis.

  • Reinstall the trim ring and 8 screws, reinstall the knobs.
    Unscrew and pull out the RF board PB-1433 on the right hand side toward the rear on the radio.

  • Locate where the premix coax cable solders to the board, at the circuit trace and C107, C118 is soldered. On the bottom of the board (solder side) solder one leg of a .01uF ceramic disk capacitor with the lead's short. The other leg of the .01uF cap solders to the center leg of a 10k variable resistor.

    The left leg of the resistor solders to the center lead of your RG-174 coax. The shield of the RG-174 coax is soldered to the grounded leg of L101. This is your "HFO" signal. Plug the board back into the slot and reinstall the 2 screws.

  • Remove the 4 screws and the plastic cover at the left hand side of the radio.
    The board in the very back is the AF board PB-1437. It's not necessary to remove this board.

  • Find VR501 - The carrier balance variable resistor. Solder one leg of a .01uF ceramic disk capacitor with the leg's cut short to the center of VR501. The other leg of the .01uF cap solder to the center leg of a 10k variable resistor. The left leg of the 10k variable resistor solder the center lead of the other RG-174 coax. The shield of the RG-174 solders to the grounded side of R508 This is the "BFO" signal.

  • Flip the radio over and solder the red wire of the new display unit to the brown wire mentioned earlier, heat shrink.

  • Solder the black wire to the ground lug mentioned earlier.

Check over your work.
  • Turn both of the variable resistors counter clock wise.

  • Put radio on AM, this will have the BFO in off position.

  • Turn on the radio, Time for the smoke test!

  • Try the radio in receive mode on all the bands, adjust the variable resistor on the RF board for a steady and stable readout. 15M and 10M bands this is sensitive, If it's not adjusted right it will look like your turning VFO when your not. If it's over adjusted it loads up the circuit on the 40M band and weakens the sensitivity on 40 meters. Adjust and check the bands.

  • Now flip the radio on SSB and adjust the variable resistor on the AF unit till your mode reads correctly on the display.

  • Reinstall the plastic cover and 4 screws.

  • Reinstall the bottom cover and the 12 screws.

  • Install the top cover and enjoy a very fine display and knowing where your at on the band.

Thanks to All Most All Digital!!

Front cover
Front cover

Radio top
Radio top

Behind front cover
Behind front cover

AF board
AF board

Display close
Display close

RF board
RF board

Re: Yaesu FT-301AD display mod [message #108 is a reply to message #45] Thu, 22 February 2007 15:26 Go to previous message
dilip is currently offline  dilip
Messages: 2
Registered: February 2007
Junior Member
There are few places where you can find TIL306, TIL308. One is http://www.theheadway.com They are in California and have few in stock. Though these are expensive now.

[Updated on: Thu, 22 February 2007 15:29]

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