CPL Troubleshooting & Repair of Locks 3

Question 1

A padlock shackle will not release after the correct key is fully turned. Which condition best explains this symptom?

Accepted Answer

Shackle under lateral load or tension

Answer

Padlock shackles under lateral tension or load bind the locking dog and prevent release even after the plug rotates correctly; tension must be relieved before the shackle will open.

Question 2

Which symptom most clearly indicates that a lock's plug has excessive side play (slop) within the shell?

Accepted Answer

Plug wobbles during key insertion with no binding on pins

Answer

Excessive side play causes the plug to wobble without properly engaging the pins, indicating wear between the plug and shell.

Question 3

A technician is troubleshooting a Schlage B-series deadbolt where the inside thumbturn works but the key cylinder does not retract the bolt. The most likely fault is:

Accepted Answer

Stripped cam on the cylinder

Answer

If the thumbturn operates correctly but the key side does not, the cylinder's cam that drives the bolt mechanism is the component to suspect.

Question 4

After re-assembling a cylinder, the plug does not rotate freely with the correct key but did before disassembly. The technician should first check:

Accepted Answer

Whether driver pins were accidentally swapped between chambers

Answer

Swapping driver pins of different lengths between chambers during disassembly can cause false shear lines or binding, preventing smooth rotation.

Question 5

A lever handle lock returns to the horizontal position slowly or not at all after being depressed. The technician should inspect the:

Accepted Answer

Return spring or spring cage

Answer

The lever return spring or spring cage is responsible for returning the lever to its resting position; failure of this component causes the slow or no-return symptom.

(CPL) Certified Professional Locksmith Practice Test

(CPL) Certified Professional Locksmith Practice Test

CPL Troubleshooting & Repair of Locks 3