youll want to follow this guide:
[guide|19695]
this will allow you to open the devoce and obtain access to the whammy bar. there youll want to inspect and see if there is any solder joint broken or loose wire due to the drop. if nothing visual is seen, it could be damaged internally and may want to consider replacing it. you can find the replacement here:
[guide|19141]
report back here with findings for any additional assistance if needed.