Genuine LiftMaster 050ACTBLKMC receiver logic board — the Security+ 2.0 AC board with Wi-Fi, Bluetooth and the automatic lock output, fitted to the 85870 3/4 HP AC chain drive opener (2021 on). LiftMaster lists it for lock-capable AC chain and belt drive openers manufactured after 2021; the 85870 is the only model it publishes by name.
Read the number off the old board. Yellow learn button, LOCK terminals, and 050ACTBLKMC printed along the edge. The earlier 8587WL used a different lock-capable AC board, the 050ACTWFLKMC, and the two are separate parts at LiftMaster.
Specifications
| Part number | 050ACTBLKMC |
|---|---|
| LiftMaster description | Receiver Logic Board, AC, Wi-Fi (Bluetooth enabled, lock capable) |
| Learn button | Yellow — Security+ 2.0, tri-band 310 / 315 / 390 MHz |
| Connectivity | Wi-Fi and Bluetooth for myQ |
| Lock output | Two LOCK terminals for the automatic garage door lock |
| Power | AC chain and belt drive openers, 2021 on |
| Fits | LiftMaster 85870 — see the 85870 parts page |
| Condition | Genuine LiftMaster OEM, new |
Not for the 8587W or 8587WL — those take the 050ACTBMC and 050ACTWFLKMC. Not for DC openers: the lock-capable DC board is the 050DCTBFLKMC.
Parts often replaced with it
841LM automatic garage door lock · 041-0136 safety sensors · 893LM remote · L979M keypad
Is the board actually the problem?
The logic board is the most over-ordered part on a garage door opener. Work down this list before you buy:
| Symptom | Check first |
|---|---|
| Opener completely dead — no light, no beep, nothing from the wall button | The outlet and breaker, then the line cord and the transformer. The board is last on this list, not first |
| Light comes on, motor hums but the door does not move | The capacitor on an AC unit, or a stripped drive gear. Not the board |
| Door will not close and the opener light flashes 10 times | The safety sensors — alignment, a cut wire or a sun-blinded eye. This is never the board |
| Remotes and keypad stopped working but the wall button works | Remote batteries, then re-program them to the learn button. Only if the learn button LED never lights is the receiver on the board suspect |
| Lost its Wi-Fi or myQ connection | The router, the phone app and the Wi-Fi signal in the garage — not the board. Re-run the myQ setup from the app before ordering anything |
| Runs a few inches and reverses, or stops short of the floor | Door balance and the travel and force settings first, then the travel module and RPM sensor. The board only after those |
| Learn button LED never lights, opener runs one way only, or it failed the night of a storm | The board. Surge damage is the single most common reason one of these is replaced |
After fitting
The replacement board arrives blank. After fitting it you will need to set the travel limits and force, program every remote, keypad and vehicle HomeLink to the new learn button, and re-test the safety reversal on a 2x4 laid flat on the floor. Wi-Fi and myQ do not carry over — delete the old opener from the myQ app and add it again as a new device. Re-enable the automatic lock in the myQ app and check the deadbolt throws and retracts fully before the first close.
Put the opener on a surge protector when you fit the new board. Lightning and utility surges are the most common reason a garage door opener logic board is replaced, and a new board on the same unprotected outlet is at the same risk. A plug-in surge protector rated for motors is a small cost next to a second board.
Related
85870 parts · LiftMaster opener parts · LiftMaster logic board cross reference
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.
