LiftMaster MGJ Medium-Duty Gear-Reduced Jackshaft Operator Parts

Liftmaster K20-1050C-1M-1 Motor, 1/2HP, 120V, MGJ

LiftMaster K20-1050C-1M-1 Motor 1/2 HP 120V for MGJ Commercial Operator

$384.43

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LiftMaster K75-11377 Compound Sprocket 41B19 x 1-1/4 in Bore

$58.21

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LiftMaster K32-11414 Gear Reducer 45:1 1 HP for MGJ Commercial Operator

$797.84

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LiftMaster K74-31243 MOV Kit for Logic Commercial Operators

$58.71

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Liftmaster K10-33850 E-Box, Cover, MH, MJ, MT

LiftMaster K10-33850 E-Box Cover for MH, MJ and MT Commercial Operators

$73.94

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LiftMaster K72-33872-1 Limit Switch Shaft and Sprocket Kit

$74.95

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LiftMaster K72-33872-2 Limit Switch Shaft Kit for MGJ Commercial Operators

$76.18

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LiftMaster K72-12493 Limit Switch Kit for Medium-Duty Commercial Operators

$29.50

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Liftmaster K94-33961 Wire Harness Kit, MT, MJ, MH

LiftMaster K94-33961 Wire Harness Kit for MT, MJ and MH Operators

$66.37

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Liftmaster K0016424 Logic Board, Medium Duty, U, 315MHz

LiftMaster K001A6424 Logic Board, Medium Duty U, 315 MHz

$144.95

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Liftmaster K23-10041 Limit Switch Replacement Kit (SPDT, 10A 125/250VAC) 1/2 HP

LiftMaster K23-10041 SPDT 10A Limit Switch for Select 1/2 HP Commercial Door and Gate Operators

$15.25

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Liftmaster K29-10338 Motor Capacitor 70MFD 50/60Hz 230VAC MT BMT MJ MH HMJ MHS

LiftMaster K29-10338 70 MFD 230VAC Motor Capacitor for Commercial Door Operators

$39.95

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Liftmaster K13-10024 Limit Nut Replacement Part Commercial Door Operators

$11.73

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Liftmaster K001A6424 Logic Board Medium Duty U 315Mhz Commercial Door Operators

$144.95

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Liftmaster K13-10024 2-Pack Limit Nut Replacement Part Commercial Door Operators

$22.00

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Liftmaster K29-10338 Motor Capacitor, 70MFD, 50/60Hz, 230V

$39.95

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Frequently Asked Questions : Liftmaster MGJ Medium-Duty Logic Gear-Reduced Jackshaft Operator Replacement Parts

Q1: What are the standard replacement parts for the LiftMaster MGJ operator?

A1: Common replacement components for the LiftMaster MGJ jackshaft operator include Medium-Duty Logic control boards, continuous-duty motors, and limit switch assemblies. Mechanical hardware such as the internal gear reducer, drive sprockets, and roller chains are also frequently replaced.

Q2: How do I identify the correct Medium-Duty Logic board for my MGJ operator?

A2: To find the compatible replacement control board, locate the specific part number printed directly on your existing board or refer to the operator's specification label. The replacement board must match the exact voltage and phase of the original unit.

Q3: Can the internal gear reducer on the LiftMaster MGJ be repaired if it fails?

A3: The gear reducer is a critical sealed mechanical unit designed to handle the torque required for medium-duty commercial doors. If the unit begins to leak or fails internally, the entire gear reducer assembly typically requires complete replacement by a qualified professional.

Q4: What should be done if the motor on the MGJ jackshaft operator needs replacement?

A4: Replacing a commercial operator motor involves managing high-voltage electrical connections and aligning mechanical components. For safety and operational integrity, this procedure must be completed by a licensed electrician or a local qualified commercial door technician.

Q5: Why might the limit switch assembly on the LiftMaster MGJ need to be replaced?

A5: Limit switches endure constant mechanical wear during standard commercial operations. If the door consistently over-travels or fails to stop at the designated open and close boundaries, the internal cams are likely worn and require complete replacement.

Q6: Are drive sprockets interchangeable across different LiftMaster jackshaft operators?

A6: Drive sprockets must precisely match the shaft diameter, keyway dimensions, and torque specifications of the specific MGJ operator. Always consult the manufacturer's parts diagram to select the correct mechanical sprocket to prevent system damage.

Q7: What safety peripherals are compatible with the LiftMaster MGJ operator?

A7: The MGJ operator requires continuous-monitoring safety devices, such as commercial photoelectric sensors or optical safety edges, to comply with UL 325 safety standards. Consult the manufacturer's installation manual to verify that replacement sensors communicate correctly with the logic board.

Q8: Can a damaged contactor on the LiftMaster MGJ be repaired internally?

A8: The contactor functions as a high-voltage relay that transfers power to the motor and is not designed for internal repair. When the electrical contacts become pitted from repetitive use, the entire contactor block must be replaced as a single unit.

Q9: Who is qualified to replace the internal friction clutch mechanism on the MGJ?

A9: The internal friction clutch is a tension-loaded safety mechanism designed to protect the door hardware by allowing slippage during an obstruction. Servicing or replacing this critical component requires specialized knowledge and should only be performed by a local qualified technician.

Q10: What routine maintenance is required after installing new mechanical parts on the MGJ operator?

A10: Newly installed chains, sprockets, and gear assemblies must be correctly aligned, tensioned, and lubricated according to exact factory specifications. For detailed maintenance schedules and safety testing procedures, consult the technical manual provided by the manufacturer.

LiftMaster MGJ Medium-Duty Gear-Reduced Jackshaft Operator Parts

Products [16]

Frequently Asked Questions : Liftmaster MGJ Medium-Duty Logic Gear-Reduced Jackshaft Operator Replacement Parts

Q1: What are the standard replacement parts for the LiftMaster MGJ operator?

Q2: How do I identify the correct Medium-Duty Logic board for my MGJ operator?

Q3: Can the internal gear reducer on the LiftMaster MGJ be repaired if it fails?

Q4: What should be done if the motor on the MGJ jackshaft operator needs replacement?

Q5: Why might the limit switch assembly on the LiftMaster MGJ need to be replaced?

Q6: Are drive sprockets interchangeable across different LiftMaster jackshaft operators?

Q7: What safety peripherals are compatible with the LiftMaster MGJ operator?

Q8: Can a damaged contactor on the LiftMaster MGJ be repaired internally?

Q9: Who is qualified to replace the internal friction clutch mechanism on the MGJ?

Q10: What routine maintenance is required after installing new mechanical parts on the MGJ operator?