LiftMaster K29-25-3 330-Ohm Resistor — 5W, 5% Tolerance

The LiftMaster K29-25-3 is the resistor service reference identified as 330 ohms, 5 watts and 5 percent tolerance. Those three ratings describe different electrical characteristics and all must match the approved circuit requirement. Select it by the exact operator service information rather than resistor appearance, a shortened resistance value or an assumption that any higher-wattage electronic component is an equivalent replacement. Select the replacement by the complete part number and the installed equipment configuration. A similar photograph or a shared LiftMaster brand name does not establish interchangeability. Confirm the applicable service drawing before ordering so the repair addresses the correct component and its related mounting, connection and operating requirements.

Compatibility — Models, Versions and Exclusions

Identify the Assembly and Plan the Repair

Resistance, power rating and tolerance must be considered together with the actual circuit and mounting. A resistor can operate at elevated temperature in its intended application, so the technician must preserve the documented clearances and connection arrangement. Do not infer an allowable supply voltage or circuit location from the 5W rating alone.

A failed resistor can be a symptom of another electrical fault or abnormal load. Inspect the surrounding board and wiring before replacing the component so the underlying cause is addressed. Use the specified service item and approved procedure rather than experiment with alternate values to make the operator respond.

An electrical symptom does not identify the failed component by itself. Have qualified service personnel inspect the supply, wiring, connections and equipment condition before replacing parts. Record existing labels and terminal references with power safely isolated. A replacement should restore the documented circuit arrangement; it should not be used to change operating voltage, defeat a protective function or compensate for a mechanical load that the equipment cannot safely move.

Specifications and Product Identification

Before Ordering

• Record the exact operator and circuit location.
• Match 330 ohms, 5W and 5% tolerance.
• Inspect the surrounding circuit for heat damage or faults.
• Confirm mounting, clearances and current package details.

Package Contents and Separate Requirements

This offer identifies the resistor service item. A complete circuit board, wiring harness, heat-management assembly, power supply and operator are not established as included. Confirm the current resistor package and any separately required connection or mounting pieces for the approved application.

Safety Warnings — Read Before Installation or Service

• WARNING: Electrical service can expose hazardous voltage and moving equipment. Use qualified service personnel and electrical personnel where required.
• Disconnect every applicable mains, battery and auxiliary supply before work. Follow the equipment instructions for stored energy and safe isolation.
• Do not bypass grounding, overload protection, monitored safety devices or fire-control functions to make the equipment operate. Diagnose the underlying fault.
• Restore covers and wiring protection, then complete the model-specific functional and safety checks before returning the installation to normal use.

Related Products and Important Differences

• CPS-U monitored photo eyes — separate protection devices for approved commercial-door controls; match the operator and environment.
• TDC12X1BMC MAXUM trolley operator — a complete-operator comparison, not evidence that this legacy service part fits MAXUM.

Frequently Asked Questions

Is 330 ohms the same as 330 kilohms?

No. The identified value is 330 ohms. Do not substitute a different resistance magnitude.

Does 5W describe motor power?

No. It is the resistor’s power rating and does not identify the operator’s motor capacity.

Can I use another tolerance?

Use the exact approved service specification. This reference is identified with a 5 percent tolerance.

Will replacing it fix every board fault?

No. Diagnose the surrounding circuit and correct any cause of overload or heat damage before completing the repair.

Need Help Confirming the Right Product?

Contact Garage-DoorParts.com before ordering. Send the full equipment model, readable part labels and photographs of the installed assembly. Include the dimensions, electrical configuration or accessory details relevant to your project so the listing can be checked against the actual installation.