Product Overview
The LiftMaster K76-34728 is an EMI board and power switch assembly used in select LiftMaster 24V commercial gate operators. It is not the logic board that controls gate timing, radio programming, or accessories. Instead, it sits in the power side of the operator and provides filtering and service power functions that help the operator run correctly in commercial environments.
This board is commonly replaced when the power switch, receptacles, or EMI board section is damaged, corroded, heat marked, or no longer passing power correctly. It may also be inspected after a surge event, water intrusion, or repeated power-related nuisance failures.
Because the EMI board interfaces with line voltage, the diagnosis should not be guessed from symptoms alone. The technician should confirm incoming voltage, transformer condition, fuse status, harness connections, and the main control board before deciding that K76-34728 is the failed part.
Compatible With
Commonly associated with LiftMaster 24V commercial slide and swing gate operator families, including:
- CSL24V slide gate operators
- CSL24U slide gate operators
- CSL24UL slide gate operators
- CSL24ULMC where the parts diagram confirms K76-34728
- CSW24V swing gate operators
- CSW24U swing gate operators
- CSW24UL swing gate operators
- CSW24ULMC where the parts diagram confirms K76-34728
Also Known As / Related Part Numbers
- K76-34728
- 76-34728
- LM-K76-34728
- LiftMaster K76-34728
- EMI board
- EMI board with power switch
- Power switch board
- CSW24 EMI board
- CSL24 EMI board
Features & Specifications
| Manufacturer | LiftMaster |
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| Product Type | EMI board with power switch |
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| Part Number | K76-34728 |
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| Application | Power filtering and service switch assembly |
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| Compatible Operator Type | Select 24V commercial swing and slide gate operators |
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| Voltage | Includes 120V receptacle / power switch functions on compatible units |
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| Common Model Families | CSW24 and CSL24 series |
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| Notes | Confirm board number and wiring layout before ordering |
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Technician Note
If the operator is dead or intermittent, do not assume the EMI board is the only failed component. Check incoming power, fuses, transformer output, surge damage, and board harnesses before replacing parts.
Before Ordering
- Confirm the operator is a compatible CSW24 or CSL24 family unit.
- Match the original EMI board or parts diagram to K76-34728.
- Verify voltage and receptacle/power-switch configuration.
- Inspect the control box for water, insects, heat damage, and surge marks.
- Have a qualified technician perform all line-voltage testing.
Important Ordering Warnings
- Not the main logic/control board.
- Not a universal power board for all LiftMaster gate operators.
- High-voltage wiring is present in this area of the operator.
Professional Advisory
Never bypass the power switch, grounding, EMI filtering, fusing, or safety devices to force a gate operator to run. Correct the electrical fault before returning the system to service.
Product Questions & Answers
What does the K76-34728 EMI board do?
It helps manage line power at the operator and provides EMI filtering, built-in 120V receptacles, and an AC power switch on compatible CSL24 and CSW24 commercial gate operators.
Which operators commonly use this EMI board?
It is commonly listed for LiftMaster CSL24V, CSL24U, CSL24UL, CSW24V, CSW24U, and CSW24UL commercial slide and swing gate operators.
Is K76-34728 the same as the main control board?
No. This is the EMI board with power switch and receptacles. It is separate from the main control board, battery charging system, expansion board, and accessory wiring.
Can this board fix a dead operator?
It may be involved in a power issue, but a dead operator can also be caused by incoming power, fuses, transformer failure, surge damage, battery issues, or main board failure. Diagnose before replacing parts.
Does this part require electrical experience?
Yes. This board is part of the operator power system. Installation and diagnosis should be handled by a qualified gate technician.
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