FT-891 Headset Noise Modification

| diciembre 23, 2018

FT-891 Headset Noise Modification

Headset Noise-Modification FT-891

Situation

When listening quietly with the headset, noises will interfere with changes to the display, for example from the S-Meter. The background noise is also annoying when you hear at a low volume.

The problem is related to the sensitivity of the headset and maybe to the serial number of the FT-891. Mine is 6K050037.

Modification

The modification is done in the panel-unit. Installation of two 10 Ohm resistors, which are connected in parallel to the left and right channel of the headphones to the ground. Then the disturbing noises are attenuated and are no longer perceived.

Schematic

  • The connection points of the two resistors are drawn in fuchsia.
  • The factory fitted jumpers are marked green-black.

FT-891 Headset Noise Modification

Picture before the Modification

The connection points of the two resistors and the grounding point are drawn in fuchsia colors.

FT-891 Headset Noise Modification


Picture with the Modification done

FT-891 Headset Noise Modification

How to open the Panel-Unit

Unscrew the 4 screws labeled with “1”.

FT-891 Headset Noise Modification

Peter Sidler – HB9PJT

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