JDC, RJDC, JHDC Maxum Jackshaft & Hoist Parts
LiftMaster Maxum JDC, RJDC & JHDC Replacement Parts
Genuine LiftMaster replacement parts for the Maxum industrial DC jackshaft and hoist operators — models JDC, RJDC and JHDC. Find your part number in the tables below and click it to go straight to that item.
Which operator do I have? All three are wall-mount DC operators built on the same control platform, and they share the main board, EMI boards, transformers and control box. What separates them is the disconnect:
JDC — jackshaft, no hoist and no manual release. Battery backup is included so the door can be run during a power failure.
RJDC — jackshaft with a manual release. Pull the sash chain to disconnect the operator from the door. Built left-hand (RJDC7S1BEL, RJDC7S4BEL) and right-hand (RJDC7S1BER, RJDC7S4BER) — the handing is not field-changeable, so order frame and release parts to match your unit.
JHDC — jackshaft with a hoist. A green engage rope and a red disengage rope electronically disable the controls so the door can be moved by hand chain.
Trolley (TDC) models are a different machine — see TDC Maxum Trolley Operator Parts.
Models Covered
JDC jackshaft (700 lb): JDC7S1BMC, JDC7S4BMC, JDC7S1BE, JDC7S4BE.
RJDC jackshaft with manual release (700 lb): RJDC7S1BEL, RJDC7S4BEL, RJDC7S1BER, RJDC7S4BER.
JHDC hoist (700 lb): JHDC7S1BMC, JHDC7S4BMC, JHDC7S1BE, JHDC7S4BE.
JHDC hoist (1200 lb): JHDC12S1BMC, JHDC12S4BMC, JHDC12X1BMC, JHDC12X4BMC, JHDC12S1BE, JHDC12S4BE, JHDC12X1BE, JHDC12X4BE.
JHDC hoist (2200 lb): JHDC22X1BMC, JHDC22X4BMC.
How to read your model number: the frame letters come first (J = jackshaft, RJ = jackshaft with release, JH = jackshaft with hoist), then DC, then the door weight (7 = 700 lb, 12 = 1200 lb, 22 = 2200 lb), then the duty cycle (S = standard, X = extended/continuous), then the voltage (1 = 120/240V single or three phase, 4 = 480V three phase), then B for battery backup, then E for the 3-inch extended shaft. MC carries no significance. On the RJDC only, a trailing L or R is the handing. Ordering motors, frames and sprockets correctly depends on the weight, the duty letter and the shaft size, so read the full number off the operator's label.
Motor, Gear Box & Encoder Assemblies
These are the complete drive assemblies. The motor's own part number is printed on the motor's data label — if you can reach it, read the number off the label and match it below; that is the most reliable way to order the right motor. Note that the 700 lb units are split by shaft size: the standard 2-inch shaft and the 3-inch extended shaft ("E" models) take different assemblies.
| Part # | Description |
|---|---|
| K41-0539-000 | Motor, Gear Box & Encoder — RJDC7 |
| K41-0374-000 | Motor, Gear Box & Encoder — JDC/JHDC 700, non-3 in. shaft |
| K41-0540-000 | Motor, Gear Box & Encoder — JDC/JHDC 700, 3 in. shaft |
| K41-0375-000 | Motor, Gear Box & Encoder — JHDC12S, non-3 in. shaft |
| K41-0409-000 | Motor, Gear Box & Encoder — JHDC12X, non-3 in. shaft |
| K41-0595-000 | Motor, Gear Box & Encoder — JHDC12S, 3 in. shaft |
| K41-0376-000 | Motor, Gear Box & Encoder — JHDC22X |
Motors, Brushes & Encoder
Service-level motor parts, for when the gearbox is sound and only the motor or its wear items need replacing. The brush kit fits the extended and continuous duty "X" models.
| Part # | Description |
|---|---|
| K41-0424-000 | Motor with Endcap — JDC, RJDC, JHDC, TDC 700 standard duty |
| K41-0425-000 | Motor with Endcap — JHDC, TDC 1200 standard duty |
| K41-0426-000 | Motor with Endcap — JHDC, TDC 1200 extended/continuous duty |
| K41-0427-000 | Motor with Endcap — JHDC, TDC 2200 extended/continuous duty |
| K41-0413-000 | Motor Brushes (4) — extended/continuous duty X models |
| K41-0469-000 | Motor Cap only — RJDC7, JDC7 and TDC7/12/22 |
| K41-0387-000 | Encoder, with drive sprocket, snap ring, mounting plate and screws |
Control Box & Electronics
The main board is common to every Maxum operator. The EMI board is not — there is a 480VAC board and a separate 120/240VAC board, and fitting the wrong one is the most common ordering mistake on this platform. Check the voltage digit in your model number (1 = 120/240V, 4 = 480V) before you order.
| Part # | Description |
|---|---|
| K41-0388-000MC | Main Board — all Maxum operators |
| K41-0390-000 | EMI Board — all Maxum operators, 480VAC |
| K41-0391-000 | EMI Board — all Maxum operators, 120/240VAC |
| K41-0395-000 | Control Box with Cover (front, back and hardware) |
| K41-0380-000 | Bridge Rectifier — 700 and 1200 |
| K41-0478-000 | Bridge Rectifier — 2200 |
| K77-36541 | Antenna |
Toroidal Transformers & Covers
Transformers are sized to the door weight and the supply voltage — six combinations, all different parts. Match both before ordering.
| Part # | Description |
|---|---|
| K41-0381-000 | Toroidal Transformer — 700, 120VAC-240VAC |
| K41-0382-000 | Toroidal Transformer — 700, 480VAC |
| K41-0383-000 | Toroidal Transformer — 1200, 120VAC-240VAC |
| K41-0384-000 | Toroidal Transformer — 1200, 480VAC |
| K41-0385-000 | Toroidal Transformer — 2200, 120VAC-240VAC |
| K41-0386-000 | Toroidal Transformer — 2200, 480VAC |
| K41-0428-000 | Transformer Cover — T, J, RJ and JH, 700 & 1200 |
| K41-0429-000 | Transformer Cover — TDC22 and JHDC22 |
Frames & Drive Sprockets
The RJDC and JHDC have their own frames, listed in their own sections below. The 12-tooth sprocket below is the standard fitment; a 10-tooth kit is available to slow the door about 20% — see the accessories page.
| Part # | Description |
|---|---|
| K41-0551-000 | Operator Frame — JDC/JHDC7 and JHDC12 |
| K41-0566-000 | 12-Tooth Operator Sprocket, #50 chain — JDC7, RJDC7, JHDC7/12 |
JHDC Hoist Parts (JHDC Models Only)
The hoist chain and the engage/disengage ropes are sized to the installation, not to the operator — measure before ordering. The hoist assembly ships with the red and green ropes but without the hoist chain.
| Part # | Description |
|---|---|
| 1910929FT12 | Hoist Chain — 12 ft length |
| 1910929FT25 | Hoist Chain — 25 ft length |
| K41-0269-000 | Disengage and Engage Ropes — 15 ft length |
| K41-0549-000 | Disengage and Engage Ropes — 29 ft length |
| K41-0479-000 | Hoist Assembly with red/green ropes, no hoist chain — JHDC 700, 1200 & 2200 |
| K41-0480-000 | Operator Frames, left and right sides — JHDC 2200 |
RJDC Manual Release Parts (RJDC Models Only)
The RJDC7 frame is handed. Confirm whether your unit is an L or an R from the last letter of the model number before ordering the frame.
| Part # | Description |
|---|---|
| K41-0541-000 | Operator Frame — RJDC7 |
| K41-0542-000 | Manual Release Subassembly — RJDC7 |
| K41-0548-000 | Plastic Cover only, for Manual Release — RJDC7 |
2200 lb Models Only
The 2200 lb units add an electromechanical holding brake on top of the dynamic braking fitted to every Maxum. The 700 and 1200 do not use this kit.
| Part # | Description |
|---|---|
| K41-0476-000 | Service Kit, Brake only — 2200 models |
Common Maxum Faults
| Symptom | Likely part |
|---|---|
| Door runs to the wrong position or limits drift | Encoder K41-0387-000, or the full motor/gearbox/encoder assembly |
| No response at all, no display on the wall controller | Toroidal transformer for your weight and voltage, or bridge rectifier |
| Operator dead after a lightning event or line surge | EMI board — K41-0390-000 (480VAC) or K41-0391-000 (120/240VAC) |
| Motor runs weak, sparks, or smells hot on an X model | Motor brushes K41-0413-000 |
| Remotes and accessories stopped pairing | Antenna K77-36541, or main board K41-0388-000MC |
| JHDC hoist chain slips or ropes will not disengage | Hoist assembly K41-0479-000, ropes K41-0269-000 or K41-0549-000 |
| RJDC release will not re-engage | Manual release subassembly K41-0542-000 |
| 2200 lb door drifts down when stopped | Brake service kit K41-0476-000 |
Related
TDC Maxum Trolley Operator Parts · Maxum DC Operator Accessories & Kits · Complete Maxum DC Operators
Not sure which part you need? Have your full model number and serial number ready from the operator's label and give us a call — we work on these units every day.