Is your alarm clock under the two-year warranty? If so, check the manufacturer's website as follows on how to return your clock to them for repair or replacement:
If your clock is not under warranty, you can replace these knobs yourself. You will need to locate a replacement part on the following website:
After you have purchased the replacement part, follow these directions to replace the alarm and time setting knobs:
Using a standard flat head screwdriver, remove the black battery compartment cover, which is located on the back of the alarm clock towards the bottom between the alarm clock legs by lifting gently on tab with the screwdriver. Remove (1) "AA" battery from the battery compartment. Set battery aside.
Remove the three small silver screws located at the top and both sides of the back cover using the #1 Phillips screwdriver which is in the iFixit toolkit. Remove the black back cover of the alarm clock by gently pulling upward being careful not to disconnect the wires which are attached to the back cover.
The alarm and time setting knobs are identified as black posts attached to an opaque wiring box, which is located towards the upper center of the inside of the alarm clock. Remove the wiring box by gently pulling upward.
The following replacement guide shows photos to follow for setting knob replacement:
Equity Alarm Clock 13014 Setting Knob Replacement
After replacement of the wiring box, repeat steps above in reverse order to reassemble the alarm clock.