Acer Extensa 4120, Service Manual

Page: 82 / 143

72 Chapter 4
POST Beep Codes
No beep, power indicator turns on, the LCD
screen is blank, but you can view POST
when connected to an external CRT. Reconnect the LCD-CCD cable.
LCD-CCD cable
Inverter board
LCD panel
System board
No beep, power indicator turns on and a
blinking cursor appears on screen during
POST. Ensure every internal cables are properly and securely
connected.
System board
No beep during POST but system runs
correctly. Speaker
System board
Code Beeps POST Routine Description
02h Verify Real Mode
03h Disable Non-Maskable Interrupt (NMI)
04h Get CPU type
06h Initialize system hardware
08h Initialize chipset with initial POST values
09h Set IN POST flag
0Ah Initialize CPU registers
0Bh Enable CPU cache
0Ch Initialize caches to initial POST values
0Eh Initialize I/O component
0Fh Initialize the local bus IDE
10h Initialize Power Management
11h Load alternate registers with initial POST
values
12h Restore CPU control word during warm
boot
13h Initialize PCI Bus Mastering devices
14h Initialize keyboard controller
16h 1-2-2-3 BIOS ROM checksum
17h Initialize cache before memory autosize
18h 8254 timer initialization
1Ah 8237 DMA controller initialization
1Ch Reset Programmable Interrupt Controller
20h 1-3-1-1 Test DRAM refresh
22h 1-3-1-3 Test 8742 Keyboard Controller
24h Set ES segment register to 4 GB
26h Enable A20 line
28h Autosize DRAM
29h Initialize POST Memory Manager
2Ah Clear 215 KB base RAM
2Ch 1-3-4-1 RAM failure on address line xxxx
Error Message FRU/Action in Sequence
Acer TM 4520 SG.book Page 72 Friday, June 22, 2007 5:43 PM