--- title: Unknown code recovery description: Archive, 2740A, 2740 High-Security Lock --- [Skip to content](https://resources.sargentandgreenleaf.com/migration/knowledge/knowledgebase/2017/02/24/unknown-code-recovery#main-content) English Show submenu for translations [Get Support](https://resources.sargentandgreenleaf.com/migration/knowledge/kb-tickets/new?hsLang=en) [Customer portal](https://resources.sargentandgreenleaf.com/tickets-view?hsLang=en) ![sg\_logo\_horiz\_rgb\_trans.png\]](https://resources.sargentandgreenleaf.com/hs-fs/hubfs/SandG%20Logos/sg_logo_horiz_rgb_trans.png?height=40&name=sg_logo_horiz_rgb_trans.png) Open main navigation Close main navigation - English Show submenu for translations - [Get Support](https://resources.sargentandgreenleaf.com/migration/knowledge/kb-tickets/new) - [Customer portal](https://resources.sargentandgreenleaf.com/tickets-view) - Main site Main site Hello. How can we help you? - There are no suggestions because the search field is empty. 1. [Help Center](https://resources.sargentandgreenleaf.com/migration/knowledge?hsLang=en) 2. [Archive](https://resources.sargentandgreenleaf.com/migration/knowledge/archive?hsLang=en) 3. [2740A](https://resources.sargentandgreenleaf.com/migration/knowledge/archive?hsLang=en#2740a) # Unknown code recovery ## Archive, 2740A, 2740 High-Security Lock To recover from a lost or unknown combination, you will need the six-digit serial number stamped into the lock case below the bolt and on the circuit board located on the inside of the cover (see photographs below). Divide the serial number into three two-digit numbers. This will be your recovery combination. You will also need to make up a new operating combination, as the recovery process requires you to enter a new operating combination. The unknown combination function is activated by pressing the setup module button for one second when the LED next to the unknown code icon is blinking. When this function is selected, the red and yellow LEDs will blink and the lock will beep six times. **[2740 Setup Module Unknown Code Recovery](https://www.youtube.com/watch?v=nygy3GS_b8I&feature=plcp)**   **Applicable to:** 2740 High-Security Lock - [Electronic Push Button Locks](https://resources.sargentandgreenleaf.com/migration/knowledge/electronic-push-button-locks?hsLang=en#main-content) - [A-Series™](https://resources.sargentandgreenleaf.com/migration/knowledge/electronic-push-button-locks?hsLang=en#a-series) - [Digital Time Lock](https://resources.sargentandgreenleaf.com/migration/knowledge/electronic-push-button-locks?hsLang=en#digital-time-lock) - [Model 6123](https://resources.sargentandgreenleaf.com/migration/knowledge/electronic-push-button-locks?hsLang=en#model-6123) - [Model 6124, 6125](https://resources.sargentandgreenleaf.com/migration/knowledge/electronic-push-button-locks?hsLang=en#model-6124-6125) - [Spartan™](https://resources.sargentandgreenleaf.com/migration/knowledge/electronic-push-button-locks?hsLang=en#spartan) - [Titan™](https://resources.sargentandgreenleaf.com/migration/knowledge/electronic-push-button-locks?hsLang=en#titan) - [Keypads](https://resources.sargentandgreenleaf.com/migration/knowledge/electronic-push-button-locks?hsLang=en#keypads) - [Mechanical Spin Dial Locks](https://resources.sargentandgreenleaf.com/migration/knowledge/mechanical-spin-dial-locks?hsLang=en#main-content) - [8400-8500 Series](https://resources.sargentandgreenleaf.com/migration/knowledge/mechanical-spin-dial-locks?hsLang=en#8400-8500-series) - [Model 2937](https://resources.sargentandgreenleaf.com/migration/knowledge/mechanical-spin-dial-locks?hsLang=en#model-2937) - [Model 6730, 6731, 6741](https://resources.sargentandgreenleaf.com/migration/knowledge/mechanical-spin-dial-locks?hsLang=en#model-6730-6731-6741) - [Padlocks](https://resources.sargentandgreenleaf.com/migration/knowledge/padlocks?hsLang=en#main-content) - [Model 8077](https://resources.sargentandgreenleaf.com/migration/knowledge/padlocks?hsLang=en#model-8077) - [ATM Locks](https://resources.sargentandgreenleaf.com/migration/knowledge/atm-locks?hsLang=en) - [Archive](https://resources.sargentandgreenleaf.com/migration/knowledge/archive?hsLang=en#main-content) - [2740A](https://resources.sargentandgreenleaf.com/migration/knowledge/archive?hsLang=en#2740a) - [Z02](https://resources.sargentandgreenleaf.com/migration/knowledge/archive?hsLang=en#z02) - [IP Lock](https://resources.sargentandgreenleaf.com/migration/knowledge/archive?hsLang=en#ip-lock) - [6300](https://resources.sargentandgreenleaf.com/migration/knowledge/archive?hsLang=en#6300) - [2890B](https://resources.sargentandgreenleaf.com/migration/knowledge/2890b?hsLang=en#main-content) - [2890B](https://resources.sargentandgreenleaf.com/migration/knowledge/2890b?hsLang=en#2890b) - [Audit Lock, Model 6126, Model 6127, Model 6128](https://resources.sargentandgreenleaf.com/migration/knowledge/audit-lock-model-6126-model-6127-model-6128?hsLang=en#main-content) - [Audit Lock, 6126, 6127, 6128](https://resources.sargentandgreenleaf.com/migration/knowledge/audit-lock-model-6126-model-6127-model-6128?hsLang=en#audit-lock-6126-6127-6128) - [All Locks](https://resources.sargentandgreenleaf.com/migration/knowledge/all-locks?hsLang=en) - [2740B](https://resources.sargentandgreenleaf.com/migration/knowledge/2740b?hsLang=en) [![Chill listening crop-3](https://resources.sargentandgreenleaf.com/hs-fs/hubfs/SandG%20Logos/sg_logo_horiz_rgb_trans.png?width=88&height=32&name=sg_logo_horiz_rgb_trans.png "Chill listening crop-3")](http://www.sargentandgreenleaf.com?hsLang=en) Sargent and Greenleaf Help Center Copyright © 2026, Sargent and Greenleaf