LiftMaster Electrical Box Parts — MT, BMT, MJ, MH and HMJ Operators
Genuine replacement parts for the electrical box fitted to LiftMaster medium-duty commercial door operators. One box design serves the MT and BMT trolley, the MJ jackshaft, the MH hoist and the HMJ hoist-jackshaft, so the internal parts below are shared across all five.
The complete box is model and voltage specific — and handed on the MH and HMJ. Order the whole box from the first table, or individual components from the tables below it. Parts marked no longer available have been discontinued and are listed for identification only.
Complete Electrical Boxes
Match your operator model, voltage and hand. The model number is on the operator's data label.
| Model |
Part # |
Description |
| MT5011 |
K-MT5011 |
Electrical Box, 115V |
| MT5025 |
K-MT5025 |
Electrical Box, 230V 50Hz (no longer available) |
| BMT5011 |
K-BMT5011 |
Electrical Box, 115V |
| BMT5025 |
K-BMT5025 |
Electrical Box, 230V 50Hz (no longer available) |
| MJ5011 |
K-MJ5011 |
Electrical Box, 115V (no longer available) |
| MJ5025 |
K-MJ5025 |
Electrical Box, 230V |
| MH5011R |
K-MH5011R |
Electrical Box, 115V right hand (no longer available) |
| MH5025R |
K-MH5025R |
Electrical Box, 230V right hand |
| MH5025L |
K-MH5025L |
Electrical Box, 230V left hand |
| HMJ5011R |
K-HMJ5011R |
Electrical Box, 115V right hand (no longer available) |
| HMJ5011L |
K-HMJ5011L |
Electrical Box, 115V left hand (no longer available) |
| HMJ5025R |
K-HMJ5025R |
Electrical Box, 230V right hand (no longer available) |
| HMJ5025L |
K-HMJ5025L |
Electrical Box, 230V left hand (no longer available) |
Box Components
| Ref |
Part # |
Description |
| 2 |
10-10316 |
Electrical Box Cover (no longer available) |
| 3 |
23-10916 |
SPDT Interlock Switch — not fitted on MT (K23-10916) |
| 4 |
K29-2 |
Resistor, 2 Ohm |
| 5 |
42-10040 |
Terminal Assembly, 3 lug (K42-10040) |
| 6 |
42-110 |
Terminal Block, 10 position (K42-110) |
| 7 |
K71-10345 |
RPM Sensor Board — MT only |
| 8 |
74-10352 |
RPM Sensor Board Harness (K74-10352) |
| 9 |
21-10340 |
Transformer — 115V models (K21-10340) |
| 9 |
21-5230 |
Transformer — 230V models (K21-5230) |
| 10 |
24-24-1 |
Relay, 24V DPDT — MT5011 and MT5025 (K24-24-1) |
| 10 |
24-24-6 |
Relay, 3PDT 24V (K24-24-6) |
| 11 |
29-12110 |
Capacitor, 20 MFD |
| 11 |
K29-10338 |
Capacitor |
| — |
K31-10350 |
Standoff |
| — |
K1A6424-2 |
Logic Board, medium duty, E, 315MHz (no longer available) |
Limit Shaft & Limit Switch — L and S Groups
The limit shaft assembly is shown on the dashed lines in the diagram. Most limit faults are cured by the shaft kit or the switch kit rather than individual pieces.
| Ref |
Part # |
Description |
| L1 |
11-10321 |
Limit Shaft (K11-10321) |
| — |
K72-12487 |
Limit Shaft Kit — models F, MT, BMT and MJ |
| — |
K72-33872-1 |
Limit Switch Shaft and Sprocket — MT, BMT, MH, MJ |
| — |
K75-12493 |
Limit Switch Kit (K72-12493) |
Upgrade Kits & Options
Safety Sensors & Edges
| Part # |
Description |
| CPS-U |
Commercial photo eye |
| CPSUN4G |
Monitored through-beam photo eyes |
| CPS |
Safety eye sensors — mechanical operators |
| CPS-UN4 |
Safety eye sensors — commercial doors |
| K77-16011 |
Mounting hardware, CPS N4 |
| 65-5302 |
Pneumatic sensing edge, 22 ft, with take-up reel |
| LC-36A |
Safety eye sensors (no longer available) |
