Liftmaster MADCBB MATDCBB MASDCBB Barrier Parts
LiftMaster MADCBB, MATDCBB, MASDCBB & MASTDCBB Replacement Parts
Genuine LiftMaster replacement parts for the Mega Arm family of barrier gate operators — the 1/2 HP, 24 VDC battery-backup barrier operators with a 60:1 gear box and a belt drive. All four models share the same parts list; the tower versions differ only in the chassis and cover.
Standard or Tower? The MADCBB and MASDCBB use the MA006 chassis and MA020 cover. The tower models MATDCBB and MASTDCBB use the MA006T frame and MA020T cover. Everything else on this page fits all four.
Shear pin by arm size. Ref 12 splits two ways — MA013 is the #6 pin and MA0137 is the #7. The shear pin is designed to break on impact, so keep spares.
Arm end caps by arm diameter: MA040 for a 2 inch arm, MA040-3 for a 3 inch arm. Measure before ordering.
Match the chip to the operator. The control board takes a model-specific chip — Mega Arm, Trap, Sprint and Slide/Swing each have their own. Fitting the wrong chip will make the operator behave like a different machine.
Match the motor brushes to your motor series. MA003B, MA003C and MA003E fit the B, C and E series motors respectively; the series letter is on the motor label.
Common Mega Arm Repairs
| Symptom | Usual cause | Parts to check |
|---|---|---|
| Arm fell off or flops loose after an impact | Shear pin done its job | MA013 or MA0137 shear pin, MA010 gate arm bracket |
| Motor runs but the arm does not move | Drive belt slipping or glazed | MA007 belt, MA008 and MA009 pulleys |
| Arm overruns or stops at the wrong angle | Magnet or cam arm out of position | MA011 magnet, MA012 cam arm |
| Operator dead, nothing at all | Fuse, transformer or on/off switch | 072A0057 and K072A0035 fuses, MA015 transformer, K23-20088 switch |
| Intermittent operation, motor sparking | Motor brushes worn — match your motor series | MA003B, MA003C, MA003E brushes |
| Grinding or heavy noise from the gear box | Gear box worn | MA005 gear box, 60:1 |
| End play or knocking at the output shaft | Shaft collar or nylon washer worn | MA036 shaft collar, MA037 shaft washer |
| Board resets or behaves like another model | Wrong or failed chip | K-127A0110B and the other Mega Arm chips |
Barrier Gate Repair & Service Parts
| Ref | Part # | Description |
|---|---|---|
| 1 | K79-60166 | Control Board, MA / MAT |
| 2 | MA002 | Connector, 12 Pin |
| 3 | MA003 | Motor, 1/2 HP, 24 VDC, BM |
| 4 | MA005 | Gear Box, 60:1 |
| 5 | MA006 | Chassis, Mega Arm |
| 5 | MA006T | Frame, Mega Tower |
| 6 | MA007 | Belt, 4L290 |
| 7 | MA008 | Pulley, Gear Reducer, 8" |
| 8 | MA009 | Motor Pulley, 1.5" |
| 9 | MA010 | Gate Arm Bracket |
| 10 | MA011 | Magnet |
| 11 | MA012 | Cam Arm |
| 12 | MA013 | Shear Pin, #6 |
| 12 | MA0137 | Shear Pin, #7 |
| 13 | MA014 | Cover Bolts |
| 14 | MA015 | Transformer, 24V |
| 14 | 072A0057 | Fuse, 250V, 1A |
| 15 | K23-20088 | On/Off Switch, 120VAC, 15A |
| 16 | MA036 | Shaft Collar |
| 17 | MA037 | Shaft Washer, Nylon |
Parts Not Shown in Diagram
| Ref | Part # | Description |
|---|---|---|
| — | MA020 | Cover, Mega Arm |
| — | MA020D | Door Kit, Mega Arm |
| — | MA020T | Cover, Mega Arm Tower |
| — | MA021 | Nylon Arm Nuts, Qty 50 |
| — | MA022 | Arm Bolt |
| — | K10-60133 | Dust Cover |
| — | MA003B | Motor Brushes, Series B Motor |
| — | MA003C | Motor Brushes, Series C Motor |
| — | MA003E | Motor Brushes, Series E Motor |
| — | K072A0035 | Fuse, 3AB, 10A, 250V |
| — | K073A0003 | Line Filter |
| — | K74-33888 | MOV, 300V |
| — | MA040 | Arm End Cap, 2", Qty 2 |
| — | MA040-3 | Arm End Cap, 3", Qty 2 |
Control Board Chips
| Ref | Part # | Description |
|---|---|---|
| — | K-127A0110B | Chip, Mega Arm |
| — | K-127A0111B | Chip, Mega Arm, Trap |
| — | K-127A0112B | Chip, Mega Slide and Swing |
| — | K-127A0113B | Chip, Mega Arm, Sprint |
| — | K-127A0114B | Chip, Sprint and Trap |