HP T5735 Troubleshooting Guide: HP t5730 and t5735 Thin Client - Page 32

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 VGA software. 3. Initializes and configures all PCI devices. 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 t5000 units. Table 5-2 Power-On Diagnostic Test Test Description Boot Block Checksum Tests boot block code for proper checksum value DRAM Simple write/read pattern test of the first 640k of memory Parallel Port Initiates the port's driver and determines if the device is present Serial Port Tests the serial port using simple port verification test to determine if ports are present Timer Tests timer interrupt by using polling method RTC CMOS battery Tests integrity of RTC CMOS battery NAND flash device Tests for proper NAND flash device ID present 24 Chapter 5 Diagnostics and Troubleshooting