Page 94 - GIGABYTE Service Manual-v3.0-110101
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5.3.1 No Boot and Post code 25
Interrupt vector initialization done. Going to read Input port of 9042 for turbo switch (if
any).Going to read I/O port of 8042 for turbo switch (if any). Enable and initialize slot.
Test extended memory.
In this step, system is going to initialize the device on the bus of AGP, PCI or
PCI-Express, and the load SB interrupt vector initialization to memory. The defection
for this section could be cause by AGP, PCI, PCI-Express bus and device on the bus,
and all voltage, clock and signals for SB must be confirmed.
5.3.2 PCI Bus Fail
Example: NVIDIA
M55S-S3 identified by:
01. Post code 25.
02. PCI AD24 opens between of 1394IC.
03. IU2 1394IC pin open and re-solder ok.
Repairing Notes:
For repairing bus issue, must check bus data/address, clock,
Reset, control signal such as FRAME, TRDY, drive select...
Figure 5-22: PCI Bus
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