Safe lock help · Sentry Safe
Safe lock troubleshooting › Sentry Safe › Sentry S-series commercial fire safe, keypad with C and # keys (S6770)
The SentrySafe S-series commercial fire safes (the S6770 and its relatives) have a small keypad with a C (start) key and a # (finish) key, next to a key lock and the handle. You press C, your code, then #, and a melody plays while you turn the handle. This guide covers how to open it, set your personal code and user code with the M button on the back of the door, replace the four AA batteries, and what the beeps mean.
Want the whole manual? Jump to the manufacturer download links.
Is this your lock?
- A commercial fire safe (often white) with a small keypad: the numbers 1 to 9, a C key, 0, and a # key. There is a key lock beside the handle, and a small LED.
- A memory button (M) is on the back of the door, and the battery housing is below the keypad (the safe’s manual calls the keys Start button C and Finish button #).
- The model numbers in Sentry’s manual for this lock are S6770, S6370, S7371, S7771, S8371 and S8771. Models with a dial use the dial: this guide is for the ones with the keypad.
- It runs on four AA alkaline batteries. The code is 4 to 16 digits.
How to open it
- Turn the key in the cylinder lock to the right.
- Press C (the Start button). The LED flickers and the lock gives a Bi sound.
- Enter your code. The LED flickers and the lock gives a Bi sound for each key.
- Press # (the Finish button). A melody plays.
- While the melody plays, turn the handle counterclockwise and open the door.
- Sentry’s example for a code of 2000: press C, 2, 0, 0, 0, #. If it is done right, the melody rings for 4 seconds.
- Model S6520 is the one exception: it has no key in the handle, and the handle turns clockwise.
How to change the battery
The lock uses four AA alkaline batteries (we recommend Procell) in the battery housing below the keypad. Sentry says that if the LED flickers and the melody plays, but the door does not open, it is time to replace the batteries. Your personal code is not erased, even if the batteries are completely dead. Batteries last about 3 years if you open the safe three times a day.
- Sentry’s manual does not give the steps for opening the battery housing in words: see the picture in the manual (it is marked “Battery Housing”). If you cannot reach it, call us.
How to set your personal code and a user code
Do this with the safe door OPEN.
Sentry says to test the new code before you close the door: press the buttons as in the opening steps (for 2000: C 2 0 0 0 #). If it is done right, the melody rings for 4 seconds.
Set your personal code (4 to 16 digits)
- Press the M (memory) button on the back of the door. The LED flickers and the lock gives a Bi sound.
- Press 1 and then #.
- Enter your new personal code (4 to 16 digits) and press #. A melody plays.
Change your personal code without opening the door
- Press #. The LED flickers and it sounds Bi.
- Enter your current personal code, and press #. The LED stays on and the melody plays.
- Enter the new personal code and press #. A melody plays.
Set a second (user) code
- Press the M button on the back of the door.
- Press 2, and then #.
- Enter the second code (4 to 16 digits) and press #. A melody plays.
Erase the user code
- Press the M button on the back of the door.
- Press #, then 2, then #.
- Sentry’s example: to set the personal code 2000, press M, 1, #, 2, 0, 0, 0, #. To change a present personal code 1234 to 2000 without opening the door, press #, 1, 2, 3, 4, #, 2, 0, 0, 0, #.
Beeps and lights
| What you hear / see | What it means |
|---|---|
| LED flickers with a Bi sound | The key press was accepted. |
| Melody rings | The code was accepted. Turn the handle while it plays. |
| Bi Bi Bi Bi | The code was wrong. |
| LED flickers and the melody plays but the door does not open | The batteries are weak. Replace them. |
Wrong codes
An incorrect code gives four Bi sounds. If a wrong code is entered more than 5 times, the lock is paralyzed and will not work. Sentry’s manual says the lock is released by entering the original code twice in a row with the opening steps (the keys light the LED but make no sound): C, code, #, C, code, #. A melody rings when it is released. If that does not work, call us.
If it still won’t open
The LED flickers and the melody plays, but the door will not open
The batteries are too weak to open the lock. Replace all four AA batteries. Your personal code is kept.
The lock does nothing at all
Check that the key is turned to the right so the cylinder pops out, and that there are good batteries in the battery housing. Then call us.
I forgot the personal code
Please do not keep guessing: more than 5 wrong codes paralyze the lock. Call us and we will open the safe.
Download the full manufacturer instructions
This page is a quick-reference summary. For every feature and diagram, use the official manual for your model:
- SentrySafe Fire-Safe Commercial Safes owner’s manual 112394Sentry’s manual for the S6770, S6370, S7371, S7771, S8371 and S8771. Linked from SentrySafe.com’s Product Manuals page.
- SentrySafe Product Manuals (find your model)Type in your model number to get your own manual.
Need a hand?
Still stuck? We can help.
Having a hard time getting into your safe? Our technicians are trained to open malfunctioning safes professionally, so your valuables can still be safely secured. Call us or stop by.
Steve’s Lock, Safe and Alarm · 3401 N. Sepulveda Blvd, Manhattan Beach, CA 90266
More lock guides
About this guide. This is an independent guide from Steve’s Lock, Safe and Alarm, a safe and lock dealer. Brand and model names belong to their owners and are used only to help you identify your lock. We are not affiliated with the manufacturers. These steps summarize the manufacturers’ own instructions; your lock may be a different version, so if anything here does not match what your lock does, follow your manual or call us. Always change codes with the safe door open, and test the new code several times before you close the door.
Steps last checked against the manufacturer documents on October 19, 2026.