Repairing a mechanical trap requires a Craft (trapmaking) check against a DC equal to the one for building it. The cost for raw materials is one-fifth of the trap’s original market price. To calculate how long it takes to fix a trap, use the same calculations you would for building it, but use the cost of the raw materials required for repair in place of the market price.
Resetting a trap usually takes only a minute or so. For a trap with a more difficult reset method, you should set the time and labor required.