Yaesu S8101823 - Genuine Yaesu 500 Ω Rotator Position Potentiometer

The Yaesu S8101823 is a 500 Ω potentiometer installed inside the mechanical unit of various antenna rotators.

Rotator movement is mechanically transferred to the potentiometer through the gear system. Changes in resistance enable the controller to determine and display the antenna position.

After extended use, the internal resistive track may become worn, causing an unstable indicator, sudden needle movements, intermittent readings or incorrect direction information. Replacing this component can restore the position-feedback system when the fault is located in the potentiometer.

This genuine replacement part carries the Yaesu reference S8101823 and is also identified by the technical designation RA25Y20S B501K.

Main features

• Brand: Yaesu
• Genuine part number: S8101823
• Designation: RA25Y20S B501K
• Type: rotary potentiometer
• Nominal resistance: 500 Ω
• Resistance code: B501
• Function: rotator position sensor
• Installation location: inside the outdoor rotator unit
• Operation: driven by the rotator gear system
• Shaft length: approximately 10 mm on the current version
• Application: rotator repair and maintenance
• Sale unit: one piece

Compatibility

Part number S8101823 is used in various versions of the following rotators:

• Yaesu G-450
• Yaesu G-650
• Yaesu G-800
• Yaesu G-1000
• Yaesu G-1300
• Yaesu G-2000
• Yaesu G-2700
• Yaesu G-2800
• Yaesu G-500
• Yaesu G-550
• Yaesu G-5500
• Kenpro KR-400 and KR-400RC
• Kenpro KR-450
• Kenpro KR-600 and KR-600RC
• Kenpro KR-650
• Kenpro KR-800 and KR-800SDX
• Kenpro KR-1000
• Kenpro KR-1300
• Kenpro KR-2000 and KR-2000RC
• Kenpro KR-2700 and HR-2700SDX
• Kenpro KR-2800
• Kenpro KR-500, KR-500A and KR-500B
• Kenpro KR-5400 and KR-5600

In Yaesu G-5500 systems, this type of potentiometer may be used in the azimuth and elevation position mechanisms, depending on the equipment version.

Possible fault symptoms

• Unstable controller needle
• Position reading that jumps suddenly
• Incorrect antenna-direction indication
• Loss of reading at certain angles
• Difference between actual and displayed position
• Frequent need for recalibration

Supplied contents

• 1 Yaesu S8101823 500 Ω potentiometer

Gears, mounting brackets, cables, resistors, insulating sheets and other rotator components are not included unless expressly stated otherwise.

Important note

Before ordering, confirm the S8101823 part number in the technical manual or directly on the installed component. Some rotators were produced in different mechanical revisions, including older versions with attached wires and current versions with a different shaft arrangement.

Installation requires partial disassembly of the rotator, correct alignment of the gears and subsequent calibration of the position display. Replacement by a technician experienced with antenna rotators is recommended.

Do not rotate the potentiometer beyond its mechanical limits, as this may damage the component.