A probe card apparatus can comprise a tester interface to a test controller, probes for contacting terminals of electronic devices to be tested, and electrical connections there between. The probe card apparatus can comprise a primary sub-assembly, which can include the tester interface. The probe card apparatus can also comprise an interchangeable probe head, which can include the probes. The interchangeable probe head can be attached to and detached from the primary sub-assembly while the primary sub-assembly is secured to or in a housing of a test system. Different probe heads each having probes disposed in different patterns to test different types of electronic devices can thus be interchanged while the primary sub-assembly is secured to or in a housing of the test system.