Acer Aspire 1800 Service Guide

53Chapter 4
System Check Procedures
External Diskette Drive Check
Do the following steps to isolate the problem to a controller, driver, or diskette. A write-enabled, diagnostic 
diskette is required.
NOTE: Make sure that the diskette does not have more than one label attached to it. Multiple labels can cause 
damage to the drive or cause the drive to fail.
Do the following to select the test device.
1.The FDD heads can become dirty over time, affecting their performance. Use an FDD cleaning kit to clean...

Chapter 454
Keyboard or Auxiliary Input Device Check
Remove the external keyboard if the internal keyboard is to be tested.
If the internal keyboard does not work or an unexpected character appears, make sure that the flexible cable 
extending from the keyboard is correctly seated in the connector on the main board.
If the keyboard cable connection is correct, run the Keyboard Test.
If the tests detect a keyboard problem, do the following one at a time to correct the problem. Do not replace a...

55Chapter 4
Check the Power Adapter
Unplug the power adapter cable from the computer and measure the output voltage at the plug of the power 
adapter cable. See the following figure
1.If the voltage is not correct, replace the power adapter.
2.If the voltage is within the range, do the following:
TReplace the main board.
TIf the problem is not corrected, see “Undetermined Problems”.
TIf the voltage is not correct, go to the next step.
NOTE: An audible noise from the power adapter does not always indicate...

Chapter 456
Check the Battery Pack
To check the battery pack, do the following:
From Software:
1.Check out the Power Options in control Panel
2.In Power Meter, confirm that if the parameters shown in the screen for Current Power Source and Total 
Battery Power Remaining are correct.
3.Repeat the steps 1 and 2, for both battery and adapter.
4.This helps you identify first the problem is on recharging or discharging.
From Hardware:
1.Power off the computer. 
2.Remove the battery pack and measure the...

57Chapter 4
still occurs, continue next step.
Replace the CPU with another of the same specifications. If the problems still occurs, go to next 
step.
The main board may be damaged. Replace main board.
3.If the external monitor has the same problem as the internal monitor,  the main board may be damaged. 
Please insert the diagnostic disk and run the display test program and go through the sub-steps under 
step 2.
Sound Check
To determine if the computer’s built-in speakers are functioning properly,...

Chapter 458
PhoenixBIOS POST Tasks and Beep Codes
When you turn on the PC, the BIOS first performs a number of tasks, called the Power-On-Self-Test (POST). 
These tasks test and initialize the hardware and then boot the Operating System from the hard disk.
At the beginning of each POST task, the BIOS outputs the test-point error code I/O port 80h. Programmers 
and technicians use this code during troubleshooting to establish at what point the system failed and what 
routine was being performed. Some...

59Chapter 4
Terminal POST Errors
There are several POST routines that require success to finish POST. If they fail, they issue a POST 
Terminal Error and shut down the system. Before shutting down the system, the error handler issues
a beep code signifying the test point error, writes the error to port 80h, attempts to initialize the video,
and writes the error in the upper left corner of the screen (using both mono and color adapters).
The routine derives the beep code from the test point error as...

Chapter 460
POST Task Routines
The following is a list of the Test Point codes written to port 80h at the start of each routine, the beep codes
issued for terminal errors, and a description of the POST routine. Unless otherwise noted, these codes are 
valid for PhoenixBIOS.
NOTE: The following routines are sorted by their test point numbers assigned in the BIOS code. Their actual 
oder as executed during POST can be quite different.
CodeBeepsPOST Routine Description
02h Verify Real Mode
03h Disable...

61Chapter 4
3Ch Advanced configuration of chipset registers
3Dh Load alternate registers with CMOS values
42h Initialize interrupt vectors
45h POST device initialization
46h 2-1-2-3 Check ROM copyright notice
48h Check video configuration against CMOS
49h Initialize PCI bus and devices
4Ah Initialize all video adapters in system
4Bh QuietBoot start (optional)
4Ch Shadow video BIOS ROM
4Eh Display BIOS copyright notice
50h Display CPU type and speed
51h Initialize EISA board
52h Test keyboard
54h Set key...

Chapter 462
89h Enable Non-Maskable Interrupts (NMIs)
8Ah Initialize Extended BIOS Data Area
8Bh Test and initialize PS/2 mouse
8Ch Initialize floppy controller
8Fh Determine number of ATA drives (optional)
90h Initialize hard-disk controllers
91h Initialize local-bus hard-disk controllers
92h Jump to UserPatch2
93h Build MPTABLE for multi-processor boards
95h Install CD ROM for boot
96h Clear huge ES segment register
97h Fixup Multi Processor table
98h 1-2 Search for option ROMs. One long, two short...