Genuine LiftMaster K001A6424 logic board — the medium-duty U-logic control board with the built-in 315 MHz receiver, supplied as the circuit board service kit for LiftMaster's medium-duty commercial door operators built from 2010: the MT and BMT trolley, MJ jackshaft, MH and MHS hoist and MGJ gear-reduced jackshaft (5011 / 5023 / 5025 series). It is the current board for that whole family; the earlier E-logic boards (K001A6424-2 at 315 MHz, K001A6424-3 at 390 MHz) are discontinued and this kit is what LiftMaster supplies in their place.
Read the number on the board and the frequency of your remotes. The board sits in the medium-duty electrical box on the side of the operator; the number is printed on it. Remotes are 315 MHz on this board (purple learn button generation: 371LM / 373LM, or the tri-band 893MAX / 890MAX). A 390 MHz installation with older 971LM / 973LM remotes takes the K001A6424-1 instead — same board, 390 MHz receiver.
Specifications
| Part number | K001A6424 (also written K1A6424) |
|---|---|
| LiftMaster description | Kit, service, circuit board assembly, 315 MHz, 2010 onward — Logic Board, Medium Duty, U |
| Replaces | K001A6424-2 (E logic, 315 MHz) and, for 390 MHz installations, see K001A6424-1 |
| Receiver | Built-in 315 MHz: up to 20 Security+ remotes, or unlimited dip-switch remotes |
| Fits | MT5011, MT5025, BMT5011, BMT5025, MJ5011, MJ5025, MH5011R, MH5011L, MHS5011 (R / L), MGJ5011, MGJ5023, MGJ5025 — medium-duty operators built 2010 onward |
| Standard | UL325 medium-duty logic |
| Condition | Genuine LiftMaster OEM, new |
Which operators use the K001A6424
| Operator | Parts page |
|---|---|
| MT5011, MT5025, BMT5011, BMT5025 — medium-duty trolley | MT / BMT parts |
| MJ5011, MJ5025 — medium-duty jackshaft | MJ parts |
| MH5011R, MH5011L — medium-duty hoist | MH parts |
| MHS5011 — medium-duty hoist, side mount | MHS parts |
| MGJ5011, MGJ5023, MGJ5025 — gear-reduced jackshaft | MGJ parts |
Not for the standard- and industrial-duty operators. The T, GT, GH, J, H, HJ, SD and APT lines use the Logic 3 / Logic 4 / Logic 5 electrical boxes: the L3 K001A5729 and L4 K001A6837 boards are discontinued, and the current Logic 5 board is the K001D8395MC. If your box has a separate power board, you are in that family, not this one.
Parts often replaced with it
Check the RPM sensor and its harness before the board when the door runs a few inches and stops. K79-15016-1 RPM sensor · 29-31244 A/B relay · K21-14182 transformer · 893MAX remote
Is the board actually the problem?
The logic board is the most over-ordered part on a commercial operator. Work down this list before you buy:
| Symptom | Check first |
|---|---|
| Operator dead, no lights on the board | Supply, fuse and the transformer before the board |
| Door runs a few inches and stops, or reverses | RPM sensor and its harness, then the limit switches, then the board |
| Remotes do not work, wall station does | Frequency mismatch (315 vs 390) or remotes not learned; then the receiver on the board |
| Relays chatter or the door will not stop at the limit | Limit switches and the A/B/C relays before the board |
| Board dead after a storm | The board — and fit surge protection with it |
After fitting
Set the open and close limits, learn the remotes to the board (315 MHz), set the timer-to-close if used and re-test the entrapment protection (photo eyes or edge) before returning the door to service.
Fit surge protection when you fit the board. Lightning and utility surges are the most common reason a commercial operator board is replaced, and a new board on the same unprotected supply is at the same risk. The MOV kit on the electrical box is the first line; a proper surge arrester on the supply is the second.
Related
MT / BMT parts · MJ parts · MH parts · MGJ parts · all LiftMaster commercial door parts
Not sure which board you need? Send a photo of the number printed on your existing board to parts@gatehousesupplies.com or call 866-965-5599. We would rather confirm it than have you fit the wrong board.
