Monday, May 4, 2020

Radio Shack DX-398 / Sangean ATS-909 Mods Part 3 - Tuning Knob

The next part of this series covers the rotary tuning knob. The DX-398 has a good tuning knob, but it has an unwanted feature causing it to stop or "click" in small increments. It is hard to spin the dial freely while tuning for DX. This is due to the plastic notches or detents in the tning shaft that mate up with a half-circle in the metal retainer/spring assembly.

Arthur Hollingsworth  created a video on how to perform this mod - You can view it here https://youtu.be/53VKmO8mqTc?t=1172



Steps

  • Locate 6 solder pads on the circuit board near the LCD display light
  • Remove the solder from the 6 pad connections
  • Remove the tuning control from the board
    Copyright Arthur Hollingsworth
  • Gently pry up the 4 metal tabs on the back of the tuning control with a small, flat bade screwdriver. Use a pair of needle nose pliers to remove any bends
    Copyright Arthur Hollingsworth
  • Gently separate the metal case and plastic control housing
    Copyright Arthur Hollingsworth
  • Remove the copper section from the 4 plastic retaining posts
    Copyright Arthur Hollingsworth
  • Using needle nose pliers, gently flatten the notch that sticks up on one side of the ring
    Copyright Arthur Hollingsworth
  • Reassemble the tuning knob in reverse order noting correct orientation (note the "detent" is now removed, but is shown here for reassembly reasons)
  • After the control has been put back together gently flatten the 4 tabs back into place using the needle nose pliers
  • Resolder the control into place on the PCB
  • Check your work and power up the radio
  • You should now be able to tune much easier now


73,
Jesse W9JES

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