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Garage Door Opener

Model # 3850 Official Chamberlain garage door opener

Here are the diagrams and repair parts for Official Chamberlain 3850 garage door opener, as well as links to manuals and error code tables, if available.

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Owner’s manual

Model diagram and schematic

SEARCH WITHIN THIS MODEL

ALL PARTS

Showing 10 of 49 parts |

Garage Door Opener Light Socket 4A1344

Garage door opener light socket

Part #4A1344

The manufacturer no longer makes this part, and there's no substitute part

Security + 4-button Remote Control 374LM

Security + 4-button remote control

Part #374LM

The manufacturer no longer makes this part, and there's no substitute part

Outside Quick Release 1702LM

Outside quick release

Part #1702LM

The manufacturer no longer makes this part, and there's no substitute part

Cover 41D504-4

Cover

Part #41D504-4

The manufacturer no longer makes this part, and there's no substitute part

Laser Park Assist 975LM

Laser park assist

Part #975LM

The manufacturer no longer makes this part, and there's no substitute part

10 Foot (3 M) Complete Rail 2770BD

10 foot (3 m) complete rail

Part #2770BD

The manufacturer no longer makes this part, and there's no substitute part

Battery 485LM

Battery

Part #485LM

The manufacturer no longer makes this part, and there's no substitute part

Surge Protector 990LM

Surge protector

Part #990LM

The manufacturer no longer makes this part, and there's no substitute part

3v2450 Lithium Battery: Proximity Switch 10A33

3v2450 lithium battery: proximity switch

Part #10A33

The manufacturer no longer makes this part, and there's no substitute part

Remote Control Visor Clip 29C151

Remote control visor clip

Part #29C151

The manufacturer no longer makes this part, and there's no substitute part

Most common symptoms to help you fix your garage door openers

Choose a symptom to see related garage door opener repairs.

Why does my garage door opener open and close by itself?

Main causes: neighbor's remote programmed at the same time as yours, faulty wall control wiring, bad wall control unit…

What preventive maintenance does my garage door opener need?

Things to do: check garage door travel, tighten brackets and fasteners, test safety sensors, check travel limits and for…

Why does my garage door opener reverse on its own?

Main causes: safety sensor beams blocked, safety sensors not aligned, downforce setting needs adjustment, damaged garage…

Why won't my garage door opener fully open or close the garage door?

Main causes: garage door opener misaligned, travel limits need adjustment, bad travel limit switches, faulty logic contr…

Why won't my garage door opener open the garage door?

Main causes: garage door locked, damaged garage door tracks, up-force setting needs adjustment, RPM sensor failure, bad …

Why is my garage door opener noisy?

Main causes: loose fasteners, broken brackets, need preventive maintenance, worn drive gears, loose or worn belt, loose …

Why doesn't my garage door opener work?

Main causes: faulty logic control board, bad RPM sensor, broken gears in the drive system, bad drive motor…

Why does my garage door opener work intermittently?

Main causes: radio interference, weak remote batteries, sunlight interference with safety sensor beams, safety sensors n…

Most common repair guides to help fix your garage door openers

These step-by-step repair guides will help you safely fix what’s broken on your garage door opener.

How to replace a chain-drive garage door opener motor

How to replace a chain-drive garage door opener motor

Get your garage door moving again by replacing a defective motor in your garage door opener.…

Repair difficulty

Time required

60 minutes or less

How to replace a chain-drive garage door opener RPM sensor

How to replace a chain-drive garage door opener RPM sensor

Learn how to replace the RPM sensor if the door only moves 6 to 8 inches at a time and the LED light flashes 5 times. …

Repair difficulty

Time required

60 minutes or less

How to replace a chain-drive garage door opener drive and worm gears

How to replace a chain-drive garage door opener drive and worm gears

If your garage door won’t move, the drive and worm gears could be broken. This guide will help you replace the gears.…

Repair difficulty

Time required

60 minutes or less

Effective articles & videos to help repair your garage door openers

Use the advice and tips in these articles and videos to get the most out of your garage door opener.

How to enjoy all the online benefits we offer on our Sears PartsDirect website

How to enjoy all the online benefits we offer on our Sears PartsDirect website

Learn about all the convenient features on our Sears PartsDirect website that make your parts purchases easier.…

Top questions about Sears and Sears PartsDirect

Top questions about Sears and Sears PartsDirect

Get answers to frequently asked questions about Sears and Sears PartsDirect.…

How to open a garage door with an opener manually

How to open a garage door with an opener manually

Learn how to open a garage door manually if power to your garage door opener fails.…

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