Audio test (Speaker test) Tests speaker. (Tests PCM and FM audio source, too.) Audio test (Use JIG) Tests the items requiring the audio jig. Remote Controller Button test Tests the operating buttons of CD-PLAYER remote control unit. Battery test Group Performs charging and discharging test of a battery. A used battery with 30% to 80% already charged battery is necessary. Battery 1 test This tests the battery 1. Battery 2 test This tests the battery 2. To perform this test, boot up the PCG-720 series without connecting the CD-ROM to the device bay 2. (CD-ROM is not necessary.) CD ROM test Tests the CD-ROM. It takes about 30 minutes. FDD Test Test the FDD. Note that the diagnostics floppy disk can be damaged, when this test ends in fail.. HDD Test Tests the HDD. Contents of HDD is destroyed when this test is performed. Be sure to make a backup of data stored in the HDD before initiating this test. It takes about three hours with the 2GB HDD and about six hours with 4GB HDD. Keyboard test Tests the keyboard. Start pressing the keyboard surely from an end of a keyboard. The Fn key is disabled. Press �Fn+End� instead. LED test Check that the LEDs start illuminating from the left of the LEDs. Main Memory Test Tests the memory. Main System Test Tests the entire system including CPU, MATH and DMA.