Toshiba Libretto 50CT/70CT Manual

							2.3  Power Supply Troubleshooting2  Troubleshooting Procedures2-8Libretto 50CT/70CT Maintenance ManualCheck 2If error code 01h displays:
q Be sure the AC adapter is firmly connected to the computer DC IN socket and
to the power source.  If these cables are connected correctly, go to the
following step:
q Replace the AC adapter with a new one.
If the error still exists, go to Procedure 4.
Check 3If error code 10h displays:
q Make sure the battery pack is correctly installed in the computer.
If it is, go to the following step:
q Replace the battery pack with a new one.
If the error still exists, go to Procedure 4.
Check 4When 88h displays, it indicates that the CPU temperature is outside the allowable
operating range. Do the following:
q Leave the computer in an area that is about room temperature until the CPU’s
internal temperature is within the allowable operating range.
If the error still exists, go to Procedure 4.
Check 5If error code 11h displays:
q Go to Procedure 3.
Check 6For any other error, go to Procedure 4. 
						

							2  Troubleshooting Procedures2.3  Power Supply TroubleshootingLibretto 50CT/70CT Maintenance Manual2-9Procedure 3Connection Check
The power supply related wiring diagrams are shown below:Any of the connectors may be disconnected.  Go to Check 1.
Check 1Make sure the AC adapter is firmly connected to the computer’s DC IN socket
and to a power source.  If these cables are connected correctly, go to Check 2.
Check 2Replace the AC adapter with a new one.  If the DC IN icon does not glow green,
go to Procedure 4.
Procedure 4Replacement Check
The AC adapter may be disconnected or damaged.  Disassemble the computer following the
steps described in Chapter 4, Replacement Procedures.  After checking the connection, do the
following checks:
Check 1 Replace the AC adapter with a new one.  If the problem still exists, go to Check 2.
Check 2 Replace the system board with a new one.  Refer to Chapter 4 for instructions on
how to remove and replace the system board. 
						

							2.4  System Board Troubleshooting2  Troubleshooting Procedures2-10Libretto 50CT/70CT Maintenance Manual2.4 System Board Troubleshooting This section describes how to determine if the system board is defective or not functioning
properly.  Start with Procedure 1 and continue with the other procedures as instructed. The
procedures described in this section are:Procedure 1:Message Check
Procedure 2:Printer Port LED Check in Boot Mode
Procedure 3:Printer Port LED Check in Hibernation Mode
Procedure 4:Diagnostic Test Program Execution and Replacement Checks
Procedure 5:Connection Check
Procedure 1Message Check
When the power is turned on, the system performs the Initial Reliability Test (IRT) installed
in the BIOS ROM.  The IRT tests each IC on the system board and initializes it.q If an error message is shown on the display, perform Check 1.
q If there is no error message, go to Procedure 2.
q If Toshiba MS-DOS or Toshiba Windows 95 is properly loaded, go to Procedure 3.
Check 1If one of the following error messages displays on the screen, press the F1 key as
instructed.  These errors occur when the system configuration preserved in the
RTC memory (CMOS type memory) is not the same as the actual configuration or
when the data is lost.
Press the F1 key as the message instructs and the TSETUP screen displays to set
the system configuration.  If error message (b) displays often when the power is
on, replace the RTC battery.  If any other error message displays, do Check 2.
(a)*** Bad HDD type ***
Check system.  Then press [F1] key ......
(b)*** Bad RTC battery ***
Check system.  Then press [F1] key ......
(c)*** Bad configuration ***
Check system.  Then press [F1] key ......
(d)*** Bad memory size ***
Check system.  Then press [F1] key ......
(e)*** Bad time function ***
Check system.  Then press [F1] key ......
(f)*** Bad check sum (CMOS) ***
Check system.  Then press [F1] key ......
(g)*** Bad check sum (ROM) ***
Check system.  Then press [F1] key ...... 
						

							2  Troubleshooting Procedures2.4  System Board TroubleshootingLibretto 50CT/70CT Maintenance Manual2-11Check 2If the following error message displays on the screen, press any key.
WARNING:  CAN’T RESTORE HIBERNATED STATE.
PRESS ANY KEY TO CONTINUE.
This error message displays when the HDD has a bad sector in the area where the
Hibernation data was stored or when the system board is faulty.  Go to Procedure
4.
NOTE: If necessary, you can bypass Hibernation by pressing thebackspace key while you power on the computer. The computer will startup in boot mode.If any other message displays, go to Check 3.
Check 3The IRT checks the system board.  When the IRT detects an error, the system
stops or an error message displays.
If one of the following error messages (1) through (17), (24) or (25) displays,
replace the system board.
If error message (18) displays, go to the Keyboard Troubleshooting Procedures in
Section 2.7.
If error message (19), (20) or (21) displays, go to the HDD Troubleshooting
Procedures in Section 2.6.
If error message (22) or (23) displays, go to the FDD Troubleshooting Procedures
in Section 2.5.
(1) PIT ERROR
(2) TIMER CH.2 OUT ERROR
(3) MEMORY REFRESH ERROR
(4) FIRST 64KB MEMORY ERROR
(5) CRT ERROR
(6) CRTC ERROR
(7) KBC ERROR
(8) VRAM ERROR
(9) SYSTEM MEMORY ERROR
(10) SYSTEM MEMORY PARITY ERROR
(11) EXTENDED MEMORY ERROR
(12) EXTENDED MEMORY PARITY ERROR
(13) DMA PAGE REGISTER ERROR
(14) DMAC #1 ERROR
(15) DMAC #2 ERROR(16) PIC #1 ERROR 
						

							2.4  System Board Troubleshooting2  Troubleshooting Procedures2-12Libretto 50CT/70CT Maintenance Manual(17) PIC #2 ERROR
(18) KB ERROR
(19) HDC ERROR
(20) HDD #0 ERR2OR
(21) HDD #1 ERROR
(22) NO FDD ERROR
(23) FDC ERROR
(24) TIMER INTERRUPT ERROR
(25) RTC UPDATE ERROR
Procedure 2Printer Port LED Check in Boot Mode
The printer port LED displays the IRT status and test status by turning lights on and off as an
eight-digit binary value for boot mode.  Figure 2-2 shows the printer port LED.Figure 2-2  Printer port LED
To use the printer port LED follow these steps:1. Plug the printer port LED into the computer’s parallel port.
2. Hold the space bar down and turn the computer on.
3. Read the LED status from left to right as you are facing the back of the computer.
4. Convert the status from binary to hexadecimal notation.
5. If the final LED status is FFh (normal status), go to Procedure 3.
6. If the final LED status matches any of the test status values in Table 2-3, do Check 1. 
						

							2  Troubleshooting Procedures2.4  System Board TroubleshootingLibretto 50CT/70CT Maintenance Manual2-13NOTE:  If an error condition is detected by the IRT test, the printer port LED displays anerror code after the IRT test ends.  For example, when the printer port LED displays 1Fand halts, the IRT test has already completed the Display initialization.  In this instance,the IRT indicates an error has been detected during the system memory test.Table 2-3  Printer port LED boot mode status (1/2)
LED statusTest itemMessage00HKBC initialization—ROM Check—02HPIT testPIT ERRORPIT initialization—PIT function checkMEMORY REFRESH ERROR
TIMER CH.2 OUT ERROR03HCMOS check
KB initializationCMOS CHECKSUM ERROR
CMOS BAD BATTERY ERROR
                                     —04HInitialization of memory
configuration—05HSM-RAM check—06HROM/RAM copy—07HSelftest skip check—Read PS Information—08HInitialization of internal
VGA0AHFirst 64 KB memory testFIRST 64KB MEMORY ERROR
FIRST 64KB MEMORY PARITY ERROR0BHSystem memory clear—0CHSystem clear—0DHInterrupt vector
initialization—18HPIC initialization—1FHDisplay initializationVRAM ERROR25HSystem memory testSYSTEM MEMORY ERROR
SYSTEM MEMORY PARITY ERROR30HExtended memory testEXTENDED MEMORY ERROR
EXTENDED MEMORY PARITY ERROR40HDMA page register testDMA PAGE REGISTER ERROR41HDMAC testDMAC #X ERROR 
						

							2.4  System Board Troubleshooting2  Troubleshooting Procedures2-14Libretto 50CT/70CT Maintenance ManualTable 2-3  Printer port LED boot mode status (2/2)
LED statusTest itemMessage42HDMAC initialization—4AHPIC testPIC #X ERRORMouse initialization—55HKBC initializationKBC ERROR60HHDD initializationHDC ERROR/HDD #0 ERROR65HFDD initializationFDC ERROR/NO FDD ERROR70HPrinter initialization—80HSIO initialization—90HTimer initializationRTC UPDATE ERROR
TIMER INTERRUPT ERRORA0HNDP initialization—A6HInitialization of expansion
ROM—C0HPassword check—FEHSetup boot check*** Bad xxxx xxxx ***
Check system.  Then press [F1] key.Boot load—Check 1If the following error codes display, go to Procedure 5.
00h, 02h, 03h, 04h, 05h, 06h, 07h, 08h, 0Ah, 0Bh, 0Ch, 0Dh,18h,
1Fh, 25h, 30h, 40h, 41h, 42h, 55h, 65h, 70h, 80h, 90h, A0h, A6h
Check 2If error code 4AH displays, go to the Keyboard Troubleshooting procedures in
Section 2.7
Check 3If error code 55H displays, go to the HDD Troubleshooting Procedures in Section
2.6.
Check 4If error code 60H displays, go to the FDD Troubleshooting Procedures in Section
2.5.
Procedure 3Printer Port LED Check in Hibernation Mode
The printer port LED displays the IRT status and test status by turning lights on and off as an
eight-digit binary value for Hibernation mode. 
						

							2  Troubleshooting Procedures2.4  System Board TroubleshootingLibretto 50CT/70CT Maintenance Manual2-15To use the printer port LED follow these steps:1. Be sure the computer is in Hibernation mode.
2. Plug the printer port LED into the computer’s parallel port.
3. Turn the computer on.
4. Read the LED status from left to right as you face the back of the computer.
5. Convert the status from binary to hexadecimal notation.
6. If the final LED status is FFh (normal status), go to Procedure 4.
7. If the final LED status matches any of the test status values in Table 2-4, go to
Procedure 5.
Table 2-4 Printer port LED Hibernation mode error status
Error statusMeaning of statusF1HSystem BIOS RAM checksum errorF2HOptional ROM or Optional Card (CGA,MDA) is connectedF7HExtended memory checksum errorE1HInstant on error (extended memory checksum error)Procedure 4Diagnostic Test Program Execution and Replacement Checks
Execute the following tests from the Diagnostic Test Menu. Refer to Chapter 3, Tests and
Diagnostics,  for more information on how to perform these tests.
System test  (1)
Memory test  (2)
Printer test  (6)
ASYNC test  (7)
Real Timer test  (9)
NDP test  (10)
Expansion test  (11)
Sound test  (12)
If an error is detected during these tests, replace the System Board with a new one.  If the
problem still exists, go to Procedure 5. 
						

							2.4  System Board Troubleshooting2  Troubleshooting Procedures2-16Libretto 50CT/70CT Maintenance ManualProcedure 5Connection Check
Check each cable connection shown in Figure 2-3, then retry the computer’s operation. If the
problem still exists, another I/O interface may be faulty.Figure 2-3 Cable connection diagram 
						

							2  Troubleshooting Procedures2.5  Floppy Disk Drive (FDD) TroubleshootingLibretto 50CT/70CT Maintenance Manual2-172.5 Floppy Disk Drive (FDD) TroubleshootingThis section describes how to determine if the 3.5-inch FDD is functioning properly.
Perform the steps below starting with Procedure 1 and continuing with the other procedures
as required.Procedure 1:FDD Head Cleaning Check
Procedure 2:Diagnostic Test Program Execution Check
Procedure 3:Connector Check and Replacement Check
Procedure 1FDD Head Cleaning Check
FDD head cleaning is one option available in the Diagnostic Program.  Detailed operation is
given in Chapter 3, Tests and Diagnostics.
Insert the Diagnostics disk in the computer’s floppy disk drive, turn on the computer, and
run the test; then clean the FDD heads using the cleaning kit.  If the FDD still does not
function properly after cleaning, go to Procedure 2.
If the test program cannot be executed on the computer, go to Procedure 2.Procedure 2Diagnostic Test Program Execution Check
Insert the diagnostics disk into the FDD, turn on the computer, and run the test.  Refer to
Chapter 3, Tests and Diagnostics, for more information about the diagnostics test
procedures.
Floppy disk drive test error codes and their status names are listed in Table 2-5.  Be sure the
floppy disk in the FDD is formatted correctly and that the write protect tab is disabled.  If
any other errors occur while executing the FDD diagnostics test, go to Check 1.Table 2-5  FDD error codes and statusesCodeStatus01hBad command02hAddress mark not found03hWrite protected04hRecord not found06hMedia removed on dual attach card08hDMA overrun error09hDMA boundary error10hCRC error20hFDC error40hSeek error60hFD not in drive80hTime out error (Not ready)