Q: Boynton Beach Florida area repair and supply shops

As the G4 is obsolete it depends on whether they have old parts in stock.

Obsolete products are those that were discontinued more than seven years ago. Apple has discontinued all hardware service for obsolete products with no exceptions. Service providers cannot order parts for obsolete products. These include ALL G4 models. On November 23, 2011 all G5 models were declared as 'vintage'. Obsolescence cannot be far behind.

http://support.apple.com/kb/HT1752?viewlocale=en_US