Mechanical and Electronic Lock Servicing
Core concepts
Mechanical servicing covers disassembly, cleaning, lubrication, pin replacement, spring replacement, and rekeying. Know that graphite is discouraged in modern locks (it cakes and attracts debris); use purpose-made lock lubricants sparingly. Understand wear patterns: worn bottom pins, weak springs, and elongated keyway wear.
Electronic locks introduce power, access control, and audit trails. Know the difference between standalone electronic locks (keypad, card, biometric) and networked access control. Understand fail-safe vs. fail-secure: fail-safe unlocks on power loss (life-safety egress), fail-secure locks on power loss (asset protection). Know credential types (PIN, proximity card, fob, smartphone), battery backup, and audit-log retrieval.
Traps in questions
- Reversing fail-safe and fail-secure.
- Assuming an electronic lock eliminates mechanical servicing - most still have a key override cylinder.
- Overlooking battery life and low-battery warning as a service call cause.
- Forgetting that electrified hardware must coordinate with the fire alarm (fail-safe on alarm).
Rule of thumb
Diagnose in order: power, credential, mechanism. If the keypad lights but the door won't open, suspect the credential or the strike; if nothing lights, suspect power/battery. On mechanical locks, service the simplest cause first (key, then cam, then pins).
Worked example
A keypad deadbolt beeps but won't retract. Check battery voltage, then confirm the user code is valid, then inspect the motor/latch. If the mechanical key override works, the electronics or motor are suspect - not the door alignment.