Power-On Sequence; Power-On Diagnostic Tests; Troubleshooting; Basic Troubleshooting - HP mt245 Maintenance And Service Manual

Power-On Sequence

At power-on, the flash boot block code initializes the hardware to a known state, then performs basic power-
on diagnostic tests to determine the integrity of the hardware. Initialization performs the following functions:
1. Initializes CPU and memory controller.
2. Initializes and configures all PCI devices.
3. Initializes VGA software.
4. Initializes the video to a known state.
5. Initializes USB devices to a known state.
6. Performs power-on diagnostics. For more information, see "Power-On Diagnostic Tests".
7. The unit boots the operating system.

Power-On Diagnostic Tests

The Power-on diagnostics performs basic integrity tests of the hardware to determine its functionality and
configuration. If a diagnostic test fails during hardware initialization the unit simply stops. There are no
messages sent to video.
NOTE: You may try to restart the unit and run through the diagnostic tests a second time to confirm the first
shutdown.
The following table lists the tests that are performed on the unit.
Test
Boot Block Checksum
DRAM
Serial Port
Timer
RTC CMOS battery
NAND flash device

Troubleshooting

Basic Troubleshooting

If the computer is experiencing operating problems or will not power on, review the following items.
Table 8-1 Power-On Troubleshooting
Issue
The computer unit is experiencing operating
problems.
66 Chapter 8 Diagnostics and Troubleshooting
Description
Tests boot block code for proper checksum value
Simple write/read pattern test of the first 640k of memory
Tests the serial port using simple port verification test to determine if ports are present
Tests timer interrupt by using polling method
Tests integrity of RTC CMOS battery
Tests for proper NAND flash device ID present
Procedures
Ensure that the following connectors are securely plugged into the computer:
Power connector, keyboard, mouse, network RJ-45 connector, monitor