FT-891 Headset Noise Modification
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.
Picture before the Modification
The connection points of the two resistors and the grounding point are drawn in fuchsia colors.
Picture with the Modification done
How to open the Panel-Unit
Unscrew the 4 screws labeled with “1”.
Peter Sidler – HB9PJT