![](/images/new-backgrounds/1122222/122222123x1.webp)
2 Troubleshooting Procedures | 2.4 System Board Troubleshooting |
Table
LED Status | Test item | Contents |
| Permission of A20 and clear of software |
|
| reset bit |
|
| Prohibition of APIC |
|
|
|
|
| Initialization of MCH, ICH |
|
|
|
|
| Initialization of Super I/O |
|
|
|
|
| Initialization of debug port (For models |
|
| supporting debug port) |
|
| Dummy read of 3rd Bus data |
|
| Setting of printer port (For models |
|
| supporting printer port) |
|
B0h | PIT CH0 initialization (for HOLD_ON) |
|
|
|
|
| BIOS rewrite factor flag initialization |
|
|
|
|
| CHECK SUM CHECK | Transition to protected mode |
|
| Boot block checksum (skipped when |
|
| returned from S3) |
|
| Halts when error occurs |
|
| Checksum other than boot block (skipped |
|
| when returned from S3) |
|
|
|
B1h | EC/KBC rewrite check | If “rewrite” is requested, go to “BIOS rewrite |
|
| process”. |
|
|
|
B2h | Initialization of SC | HLT at LED=B3H or B4, when error occurs |
|
|
|
| Key input (skipped when returned from | When a key is pressed, check if it is Tilde |
| S3) | key or Tab key. (skipped when returned from |
|
| S3) |
|
|
|
B5h | Enables CPU cache |
|
|
|
|
B6h | Security check |
|
|
|
|
| BIOS rewrite request check | If Checksum check error occurred on except |
|
| Boot Block or rewrite is required by user, go |
|
| to “BIOS rewrite process”. |
|
|
|
B7h | Transits to System BIOS IRT |
|
|
|
|
| BIOS rewrite process |
|
|
|
|
| Initialization of ICH. D31 |
|
|
|
|
| DRAM configuration |
|
|
|
|
| Permission of cache (L1 cache only) |
|
|
|
|
| Memory clear |
|
|
|
|
| Transition to real mode and copy of BIOS |
|
| to RAM |
|
|
|
|
[CONFIDENTIAL] | TECRA S3 Maintenance Manual |