Page 84 - GIGABYTE Service Manual-v3.0-110101

5.2.7 BIOS or CMOS Setting Error

Basic Input Output System: is the software embedded on a chip located on the
computer’s main board. The BIOS executes POST to test and initialize the system

components and then loads (boots) the O/S. The BIOS also handles the low-level
input/output to the various peripheral devices connected to the computer. CMOS
setting is the option which provide by BIOS include all system information, password
setting, performance setting and peripheral equipment detect... The error post code: C1,
C1-33, 05-0D-41, FF,

Because of the function of BIOS, if any data error or setting not match with system, it
would cause system lock up not only hang up at post C1 but also 05-0D-41,00,FF,...
Repair step:

01. Clear CMOS
02. Re-flash BIOS Data by SPI BIOS tool
03. Check BIOS signal.
04. Change BIOS Chip (is rarely found, so please put this step in the last of the C1
repair procedure)

Example:
EP31-DS3L identified by:
01. Post code C1, C1-33

02. BIOS signal measure by scope.
03. –SPI_HOLD0 was not pulled high.
04. R254 impedance measure fails.
Signal Explanation:
–SPI_HOLD0 (HOLD#): The HOLD# pin is used to pause a serial sequence underway

with the SPI flash memory without resetting the clocking sequence. To activate the
HOLD# mode, CE# must be in active low state. The HOLD# mode begins when the
SCK active low state coincides with the falling edge of the HOLD# signal. The HOLD

mode ends when the HOLD# signal’s rising edge coincides with the SCK active low
state.
-SPI_HOLD0 was not pulled high correctly, and SPI bus can’t not work.

Figure 5-11: BIOS or CMOS Setting Error Check

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