Acer Aspire S5-391 Acer S5-391 Notebook Service Guide - Page 102

Other Functions Failure If other functions such as the thunderbolt switch or HDMI switch, perform the following: 1. Check if the drive is ok. 2. Check if the test fixture is ok. 3. Swap the mainboard. BIOS Problems Forget BIOS Password If there is a wrong CMOS setting or the user forgets the BIOS password, discharge CMOS by shorting the R568 connector. Figure 4-37. Discharge MB CMOS Refer to Clearing the Password Check and BIOS Password on page 2-22. Random Loss of BIOS Settings If the computer is experiencing intermittent loss of BIOS information, perform the following: 1. If the computer is more than one year old, replace the CMOS battery. 2. Run a complete virus scan using up to date software to confirm the computer is virus free. 3. If the computer is experiencing HDD information loss, disconnect and reconnect the power. Troubleshooting 4-28