Description
Replacement Volume Potentiometer & Crab-Eye Nut for Motorola Mag One
Genuine Motorola Solutions Original on/off volume potentiometer switch with slotted crab-eye retaining nut for Mag One BPR40 and Alpha L radios.
The Motorola PMDN4016AR (also cataloged as PMDN4016 and PMDN4016A) is an authentic original equipment manufacturer (OEM) replacement volume potentiometer switch and retaining crab-eye spanner nut assembly engineered specifically for Motorola Mag One portable two-way radios. Designed for radio repair technicians, commercial depot service centers, and fleet maintenance shops, this component restores reliable on/off power switching and clear audio level control to heavily used portables. Sourced directly from our verified inventory of Motorola Two-Way Radios & Accessories, the PMDN4016AR eliminates scratchy volume adjustments, intermittent power shutdowns, and loose control shafts caused by daily wear or drops.
Frequent channel adjustments, jobsite impacts, and accidental drops directly onto the volume knob can crack internal carbon wiper tracks or sheer solder pins on the radio's main circuit board. The Motorola PMDN4016AR provides factory-spec rotational torque and precision resistance, ensuring smooth audio gain adjustment in demanding commercial work zones compliant with occupational safety communication guidelines under OSHA Standards. Engineered and manufactured to meet rigorous electronic assembly reliability standards under IPC Standards (IPC-A-610), the assembly features heavy-duty through-hole solder pins and an impact-resistant metal control shaft built to endure severe vibration tested under DoD Standards (MIL-STD-810H). The included precision-machined slotted crab-eye nut secures the potentiometer barrel firmly against the upper radio housing, preventing shaft wobble and compressing the chassis gasket to maintain factory dust and moisture resistance certified under IEC Standards (IEC 60529 IP54).
Key Features & Benefits
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Authentic OEM Replacement Component: Direct factory-original replacement ensures exact PCB pin spacing, switch detent tactile feel, and electrical resistance.
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Resolves Audio & Power Issues: Fixes common symptoms of failing radios, including static during volume adjustment, dead audio spots, and intermittent power cutoffs.
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Slotted Crab-Eye Nut Included: Includes the precision-threaded collar spanner nut to anchor the switch solidly against the upper chassis.
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Preserves IP54 Chassis Sealing: Threads tightly down onto the upper housing collar to compress the internal sealing gasket against moisture and dust intrusion.
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Heavy-Duty Metal Shaft: Resists rotational fatigue, lateral impact forces, and stripping when the radio knob is turned or bumped.
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Precision Rotary Resistance: Provides smooth, predictable volume tapering from low whispering levels up to full commercial audio output.
Specifications
| Attribute |
Details |
| Brand |
Motorola Solutions |
| Model / SKU |
PMDN4016AR / PMDN4016A / PMDN4016 |
| Product Type |
Replacement Volume Potentiometer Switch & Retaining Nut |
| Switch Functionality |
Integrated Rotary On/Off Power Switch with Linear Volume Control |
| Mounting Hardware |
Slotted Crab-Eye Spanner Collar Nut Included |
| Mounting Format |
Through-Hole PCB Solder Termination with Chassis Panel Mount |
| Housing Material |
Die-Cast Metal Barrel with High-Grade Contact Terminals |
| Compatible Radio Platforms |
Motorola Mag One BPR40 & Mag One Alpha L |
| Installation Requirement |
Soldering & Slotted Spanner Tool Required |
| Color / Finish |
Machined Metallic Finish with Brass Bushing |
Compatibility
Compatible Motorola Portable Two-Way Radios
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Frequently Asked Questions
What is the difference between part numbers ending in "A", "AR", or having no letter?
There is no functional, electrical, or dimensional difference. Motorola Solutions uses trailing letter suffixes (such as A or B) to indicate manufacturing revisions, while an "AR" or "R" suffix commonly denotes an authorized replacement service part kit. The parts cataloged as PMDN4016, PMDN4016A, and PMDN4016AR are physically and electrically identical, providing the exact same resistance values, PCB pin spacing, and chassis fitment.
Can this potentiometer be installed without soldering?
No. The PMDN4016AR is a component-level replacement part that is soldered directly to the radio's internal printed circuit board. Proper installation requires professional soldering equipment to desolder the damaged switch and solder the new terminals into place.
What tool is required to tighten the included crab-eye nut?
The retaining nut features two opposing slots (often called a crab-eye or spanner nut). It is tightened and loosened using a specialized radio spanner tool or crab-eye spanner bit. Using needle-nose pliers is not recommended, as they can slip and scratch the radio housing.
Will this potentiometer fix a radio that crackles when adjusting the volume?
Yes. Crackling, scratchy audio, or dead audio zones when turning the knob are classic symptoms of worn or corroded internal carbon wiper tracks inside the potentiometer. Replacing the switch with a new PMDN4016AR restores clean, quiet volume control.
Does this part include the plastic exterior volume knob?
No. This listing includes the internal electronic volume potentiometer switch and the exterior threaded slotted crab-eye nut. The exterior plastic knob cap is transferred from the existing radio or purchased separately if damaged.
Warranty
1-year manufacturer’s replacement warranty.
