TDC Maxum Trolley Operator Parts

LiftMaster Maxum TDC Trolley Operator Replacement Parts

Genuine LiftMaster replacement parts for the Maxum TDC industrial DC trolley operator. Find your part number in the tables below and click it to go straight to that item.

Models Covered

TDC 700 lb: TDC7S1BMC, TDC7S4BMC.
TDC 1200 lb: TDC12S1BMC, TDC12S4BMC, TDC12X1BMC, TDC12X4BMC.
TDC 2200 lb: TDC22X1BMC, TDC22X4BMC.

How to read your model number: T = trolley, then DC, then the door weight (7 = 700 lb, 12 = 1200 lb, 22 = 2200 lb), then the duty cycle (S = standard 20 cycles/hour, X = extended or continuous duty), then the voltage (1 = 120/240V single or three phase, 4 = 480V three phase), then B for battery-backup capable. MC carries no significance. Sprockets, frames, motors and chains all vary by weight and duty letter, so read the full number off the operator's label before ordering.

Trolley, Rail and Door Arm Assembly

Reference numbers match the assembly view above.

Operator Head — Service Kit Locations

LiftMaster services the operator head as kits, each shown as a K callout above. The Ref column in the tables that follow uses the same K numbers, so you can go from the drawing to the part. Where one callout covers several part numbers, the right one depends on your door weight (7, 12 or 22) and voltage digit (1 or 4) — read them off the model number first. The K5 in the trolley assembly view above is LiftMaster's callout for the door arm kit and is unrelated to K5 here.

TDC Service Kits — Sprockets, Frames and Motor Cap

Drive sprockets are matched to the chain pitch. The 16-tooth #41 sprocket is standard fitment on the TDC22 and is also the part used to slow a TDC12 by about 20%.

Dual Trolley Modification Kits

Dual trolley kits add a second rail to a TDC for wide or tall doors. Pick by operator model and door height — the number at the end of the part number is the maximum door height in feet. Rails ship freight.

Auxiliary trolley kits for jackshaft and hoist units, mount brackets and the auto reconnect kit are on the Maxum accessories page.

Door Drive Chain Kits

Chain kits are cut to door height. Measure your door before ordering, and confirm the pitch: #48 for the TDC 700, #41 for the TDC 1200 and 2200.

#48 chain — TDC 700

#41 chain — TDC 1200 and TDC 2200

Motor, Gear Box & Encoder Assemblies

The motor's part number is printed on the motor's own 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.

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.

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.

Toroidal Transformers & Covers

Transformers are sized to the door weight and the supply voltage — six combinations, all different parts. Match both before ordering.

2200 lb Models Only

The TDC 2200 adds an electromechanical holding brake on top of the dynamic braking fitted to every Maxum. The 700 and 1200 do not use this kit.

Common TDC Faults