These are the older Linear AC ceiling-mount openers. The manuals we have posted cover LDO33, LDO50, LSO50, and LCO75. They use 318 MHz MegaCode remotes such as the MDT-1A, ACT-34B, and NMTK keypad. Horsepower and lighting differ by model. Not every Linear AC model or manual is shown here. We post the manuals we have. Older or uncommon units may not be listed.

Shared features

• AC motor ceiling-mount openers
• 318 MHz MegaCode radio
• LDO33 is 1/3 HP; LDO50 and LSO50 are 1/2 HP; LCO75 is 3/4 HP
• Belt or chain rail depending on the kit
• Courtesy light on the operator head

LDO / LSO / LCO Manuals

LCO75 Homeowner Manual Download PDF

LCO75 Installation Manual Download PDF

LSO50 Homeowner Manual Download PDF

LSO50 Installation Manual Download PDF

LDO33 / LDO50 Homeowner Manual Download PDF

LDO33 / LDO50 Installation Manual Download PDF

Compatible remotes and parts

Here are some common compatible Linear parts. Search all Linear parts on the store: Shop Linear Parts.

NMTK Wireless Keypad

Current MegaCode keypad. Replaces MDTK and LPWKP on these LDO, LSO, and LCO operators.

Shop NMTK

ACT-34B Keychain Remote

4-button MegaCode keychain. Each button can learn to a different Linear opener.

Shop ACT-34B

MDT-1A Remote

1-button MegaCode visor remote for these LDO, LSO, and LCO operators.

Shop MDT-1A

HAE00002 Safety Sensors

Linear photo-eye safety sensors used on these residential operators.

Shop HAE00002

We don’t sell opener circuit boards. They typically aren’t the issue when experiencing problems with the operator. Go through the troubleshooting steps in the operator manual and if you still believe that you need a logic board, email store@garagedoorzone.com and we can point you to the correct part number.