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Toshiba T4850CT Maintenance Manual
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Toshiba T4850CT Maintenance Manual

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1.1
Features
The Toshiba T4850CT is one of the lightest and most advanced portable computers available.
Utilizing advanced technology and high-speed components, the T4850CT offers excellent
color display legibility, battery operation and IBM PC/AT compatibility. The T4850CT
system unit consists of the following features:
Microprocessor
TM
The Intel DX4
3.3 Volts.
Math co-processor
The math co-processor is stored in the DX4.
Cache memory
16 KB of cache memory is stored in the DX4.
Disk storage
The T4850CT has an internal 2.5-inch 500 or 810 MB HDD. The 3.5-inch FDD
supports 2 HD (1.44 MB) floppy disks and 2DD (720 KB) floppy disks.
Memory
The T4850CT comes standard with 8 MB of CMOS Random Access Memory (RAM)
3.3 Volts. This includes 640 KB of conventional memory and 7,360 KB of extended
memory which can be utilized as expanded memory compatible with the Lotus/Intel/
Microsoft Expanded Memory Specifications (LIM-EMS).
TFT color LCD
The T4850CT has a high-resolution 10.4-inch full-color, Thin Film Transistor (TFT)
color LCD that displays 640 x 480 pixels.
The internal display controller supports VGA functions on the internal display and
SVGA functions on an external display.
Keyboard
An easy-to-use 82/84-key enhanced keyboard with full-size keys and standard spacing
is compatible with IBM standard software.
T4850CT
Processor (referred to as DX4 in this manual) operates at 75 MHz,
1-1

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  • Page 1 Features The Toshiba T4850CT is one of the lightest and most advanced portable computers available. Utilizing advanced technology and high-speed components, the T4850CT offers excellent color display legibility, battery operation and IBM PC/AT compatibility. The T4850CT system unit consists of the following features:...
  • Page 2 Batteries The T4850CT has three different batteries: a main battery, backup battery, and a Real Time Clock (RTC) battery. Status indicator panel The status indicator panel is a liquid crystal display (LCD) panel which includes a battery charge indicator and 11 icons indicating the system status.
  • Page 3 The 15-pin RGB port on the back supports an external video display. Audio ports • Headphone, standard 3.5 mm diameter miniature stereo jack with speaker shut-off switch. Use a headphone with an impedance of 16 Ω . • Microphone, standard 3.5 mm diameter miniature monaural jack. T4850CT...
  • Page 4 The T4850CT Personal Computer is shown in Figure 1-1, and its system configuration is illustrated in Figure 1-2. Figure 1-1 T4850CT personal computer Figure 1-2 T4850CT system unit configuration T4850CT...
  • Page 5 System Unit Block Diagram Figure 1-3 is a block diagram of the T4850CT system unit. Figure 1-3 T4850CT system board block diagram T4850CT...
  • Page 6 VGA display controller: WD90C24A/A2 (208-pin) (3.3 volt operation) This controller controls both internal and external VGA-compatible displays and external SVGA-compatible displays with an Analog Digital Converter (DAC). The controller can display data on the internal and external display simultaneously. T4850CT...
  • Page 7 - Refresh Address Generator • I/O Register - Compatible I/O Port Register - Saving the data of the Register (in resume) Controller - Toshiba Special Register • Processing Speed Controller • Data Bus Transfer • Data Latch • Suspend/Resume Controller...
  • Page 8 IC Card Controller Gate Array This gate array performs the following functions: • IC Card Controller - PCMCIA IC Card Controller - Toshiba Modem Card Controller • EEPROM (for security) Controller - KBC-Security-EEPROM Communication Controller • Others - KBC Communication Controller...
  • Page 9 3.5-inch Floppy Disk Drive The T4850CT 3.5-inch Floppy Disk Drive (FDD) is a thin, high-performance reliable drive that supports 720-KB (formatted) 2DD and 1.44-MB (formatted) 2HD 3.5-inch floppy disks. The FDD is shown in Figure 1-4, and its specifications are listed in Table 1-1.
  • Page 10 The Hard Disk Drive (HDD) is a random access, nonvolatile storage device. It has a non- removable 2.5-inch magnetic disk and mini-winchester type magnetic heads. The T4850CT supports a 500 MB and 810 MB HDDs. The HDD is shown in Figure 1-5, and its specifications are listed in Table 1-2.
  • Page 11 Keyboard The 82-(USA) or 84-(European) keyboard is mounted on the T4850CT’s system unit, and is connected to the keyboard controller on the system board through a 19-pin flat cable. The keyboard is shown in Figure 1-6. See Appendix F for optional keyboard configurations.
  • Page 12 1.6.1 TFT Color LCD Module The T4850CT TFT color LCD supports 640 x 480 pixels with an internal display controller and 4096 colors for graphics and characters. This controller includes the functions of Video Graphics Array (VGA) and Super VGA (SVGA) for external display.
  • Page 13 1.6.2 TFT Color Fluorescent Lamp (FL) Inverter Board The FL inverter board supplies high frequency current to light the LCD’s Fluorescent Lamp. Specifications for the T4850CT’s FL inverter are listed in Table 1-4. Table 1-4 FL inverter board specifications Item...
  • Page 14 Power Supply The power supply supplies five kinds of voltages to the T4850CT system board. The power supply has one microprocessor and operates at 500 KHz (power off) or 20 MHz (power on). It performs the following functions: Determines if the AC adapter or battery is connected to the computer.
  • Page 15 Batteries The T4850CT has three types of batteries: Main battery pack Backup battery Real Time Clock (RTC) battery Battery specifications are listed in Table 1-6. Table 1-6 Battery specifications Battery name Material Output voltage Capacity Main battery Nickel Metal Hydride...
  • Page 16 A full charge is detected only when the battery is charging at quick charge, and under any of the following conditions: A battery voltage fall is detected. The charging time exceeds the fixed limit. The thermal rise (+DT) exceeds the fixed limit. The battery’s temperature is over 60° C. 1-16 T4850CT...
  • Page 17 Table 1-9 shows the charging time and data preser- vation period of the RTC battery. Table 1-9 RTC battery charging/data preservation time Item Time Charging Time Power On 24 H Power Off 24 H Data preservation period (full charge) 1 month 1-17 T4850CT...
  • Page 18 Troubleshooting Chapter 2 describes how to determine if a Field Replaceable Unit (FRU) in the T4850CT is causing the computer to malfunction. The FRUs covered are: Power Supply Board System Board(s) Floppy Disk Drive Hard Disk Drive Keyboard Display Status Indicator Panel The Diagnostic Disk operations are described in Chapter 3 and detailed replacement proce- dures are given in Chapter 4.
  • Page 19 Ask the user if a password is registered, and if it is, ask him or her to enter the pass- word. If the user has forgotten the password, contact your Toshiba representative. Verify with the customer that Toshiba MS-DOS is installed on the hard disk. Non- Toshiba operating systems can cause the computer to malfunction.
  • Page 20 Figure 2-1 Troubleshooting flowchart (1/2) T4850CT...
  • Page 21 If an error is detected on the floppy disk test, perform the floppy disk drive troubleshooting procedures in Section 2.5. If an error is detected on the hard disk test, perform the hard disk drive troubleshooting procedures in Section 2.6. T4850CT...
  • Page 22 Power Supply Troubleshooting The T4850CT’s power supply controls many functions and components in the computer. To determine if the power supply is functioning properly, start with Procedure 1 and continue with the other Procedures as instructed. The procedures described in this section are:...
  • Page 23 Charge current is over the maximum allowed limit. VCC Output Status Meaning VCC Voltage is over the maximum allowed limit. VCC Voltage is below the minimum allowed limit. VCC Voltage is output at a low level (does not fall to zero) while the power is off. T4850CT...
  • Page 24 Make sure the Desk Station IV is firmly connected to the computer’s expansion bus port. If this port is connected correctly, go to the following step. Replace the Desk Station IV with a new one. If the status still exists, go to Check 4. T4850CT...
  • Page 25 70° C degrees until its internal temperature is within that range. If the status still exists, go to Procedure 4. Check 6 When P20, P21, P22, P30, P31, P32, P33, P40, P41, P42, P50 or P60 is displayed, go to Procedure 4. T4850CT...
  • Page 26 Connect a new AC adapter. If the battery capacity does not change on the status indicator panel, go to Check 3. Check 3 Make sure the battery pack is installed in the computer correctly. If the battery pack is installed correctly, go to Procedure 3. T4850CT...

  • Page 27: Table Of Contents

    Quick Charge Check The power supply may not be charging the battery pack. Perform the following procedures. Install the battery pack on the T4850CT. Attach the AC adapter to the computer, then turn on the power. (If you cannot turn on the power, go to Procedure 4.) Run the Diagnostic test following the steps described in Chapter 3, and select System Configurations.
  • Page 28 Replacement Check The power supply board or system board(s) may be disconnected or damaged. Disassemble the T4850CT following the steps described in Chapter 4, Replacement Procedures, and check the connection between the power supply board and system board(s) and status indicator panel.
  • Page 29 If an error message is shown on the display, perform Check 1. If there is no error message, go to Procedure 2. If Toshiba MS-DOS is properly loaded, go to Procedure 3. Check 1 If any of the following error messages displays on the screen, press the F1 key as the message instructs.
  • Page 30 PIC #1 ERROR (17) PIC #2 ERROR (18) KEYBOARD ERROR (19) KBC ERROR (20) HDC ERROR (21) HDD #0 ERROR (22) HDD #1 ERROR (23) NO FDD ERROR (24) FDD ERROR (25) TIMER INTERRUPT ERROR (26) RTC UPDATE ERROR 2-13 T4850CT...
  • Page 31 If Error Message 18 displays, go to the Keyboard Troubleshooting Proce- dures in Section 2.7. If Error Message 21 or 22 displays, go to the HDD Troubleshooting Procedures in Section 2.6. If Error Message 23 or 24 displays, go to the FDD Troubleshooting Proce- dures in Section 2.5. 2-14 T4850CT...

  • Page 32: Check 1

    PRT. Figure 2-3 Printer port LED To use the printer port LED follow these steps: Turn off the T4850CT’s power. Plug the printer port LED into the computer's PRT/FDD connector. Hold down the space bar and turn on the computer.
  • Page 33 EXTENDED MEMORY ERROR ADDRESS = XXXXXXXXH READ DATA = XXXXXXXXH WRITE DATA = XXXXXXXXH EXTENDED MEMORY PARITY ERROR ADDRESS = XXXX0000H - XXXXFFFFH DMA page register test DMA PAGE REGISTER ERROR READ DATA = XXH WRITE DATA = XXH 2-16 T4850CT...
  • Page 34 If error code 4Ah is displayed, go to the Keyboard Troubleshooting procedures in Section 2.7. Check 3 If error code 5Ah is displayed, go to the HDD Troubleshooting Procedures in Section 2.6. Check 4 If error code 60h is displayed, go to the FDD Troubleshooting Procedures in Section 2.5. 2-17 T4850CT...
  • Page 35 PRT and to resume mode. To use the printer port LED follow these steps: Turn on the T4850CT’s power, then set it to resume mode. Turn off the computer. Plug the printer port LED into the computer's PRT/FDD connector.
  • Page 36 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 Memory test Printer test ASYNC test Real Timer test NDP test Expansion test If an error is detected during these tests, go to Procedure 5. 2-19 T4850CT...

  • Page 37: Check 1

    Procedure 5 Connection and Replacement Check The system board(s) may be disconnected or damaged. Disassemble the T4850CT following the steps described in Chapter 4, Replacement Procedures, and check the connection between the upper system board and lower system board, and other components. After checking the connections, perform the following checks.

  • Page 38: Check 1

    Floppy Disk Drive Troubleshooting This section describes how to determine if the T4850CT’s internal 3.5-inch floppy disk drive is functioning properly. Perform the steps below starting with Procedure 1 and continue with the other procedures as required. Procedure 1: FDD Head Cleaning Check Procedure 2: External 5.25-inch FDD Check...

  • Page 39: Check 1

    Procedure 3 Diagnostic Test Program Execution Check The Floppy Disk Drive Diagnostic Test program is stored on the T4850CT Diagnostics Disk. After loading Toshiba MS-DOS, run the diagnostic program. Refer to Chapter 3, Tests and Diagnostics, for more information about the diagnostics test procedures.

  • Page 40: Check 5

    The 3.5-inch Floppy Disk Drive is connected to the system unit by the FDD cable. This cable may be disconnected from the system board or damaged. Disassemble the T4850CT follow- ing the steps described in Chapter 4, Replacement Procedures, and perform the following checks.

  • Page 41: Check 1

    Procedure 1 Partition Check Insert the Toshiba MS-DOS system disk and turn on the computer, then perform the follow- ing checks. Type C: and press Enter . If you cannot change to drive C, go to Check 2. If you Check 1 can change to drive C, go to Procedure 2.
  • Page 42 Procedure 2 Message Check When the T4850CT’s HDD does not function properly, some of the following error messages may appear on the display. Start with Check 1 below and perform the other checks as in- structed. Check 1 If any of the following messages appear, perform Check 2. If the following mes- sages do not appear, perform Check 3.
  • Page 43 The HDD is stored inside the HDD pack. The pack connector is connected between the HDD and the lower system board. This connector may be disconnected from the lower system board or the HDD. Disassemble the T4850CT following the steps described in Chapter 4, Replacement Procedures, and perform the following checks.
  • Page 44 Procedure 4 Format Check The T4850CT’s HDD is formatted using the low level format program and the MS-DOS FORMAT program. To format the HDD, start with Check 1 below and perform the other steps as required. Check 1 Using the Toshiba MS-DOS system disk, partition the hard disk using the FDISK command.
  • Page 45 Procedure 5 Diagnostic Test Program Execution Check The HDD test program is stored in the T4850CT Diagnostics Disk. Perform all of the HDD tests in the Hard Disk Drive Test. Refer to Chapter 3, Tests and Diagnostics, for more information about the HDD test program.
  • Page 46 The HDD peripheral component is composed of the HDD, HDD pack connector, lower system board, and upper system board. One of the components may be damaged. Disas- semble the T4850CT following the steps described in Chapter 4, Replacement Procedures, and perform the following checks.
  • Page 47 Keyboard Troubleshooting To determine if the T4850CT’s keyboard is functioning properly, perform the following procedures. Start with Procedure 1 and continue with the other procedure as instructed. Procedure 1: Diagnostic Test Program Execution Check Procedure 2: Connector and Replacement Check...
  • Page 48 Display Troubleshooting This section describes how to determine if the T4850CT’s display is functioning properly. Start with Procedure 1 and continue with the other procedures as instructed. Procedure 1: Brightness Control Check (Hot Key Check) Procedure 2: External CRT Check...
  • Page 49 Check 3 Pressing the Fn+arrow keys increases or decreases the brightness of the color LCD panels. Increases the brightness of the LCD panel. Decreases the brightness of the LCD panel. 2-32 T4850CT...
  • Page 50 Procedure 2 External CRT Check Connect the external CRT to the T4850CT’s external monitor port, then press Fn+F5 . If the external CRT works correctly, the internal LCD display may be damaged. Go to Procedure 4. If the external CRT appears to have the same problem as the internal LCD, the display controller may be damaged.
  • Page 51 The upper system board may be damaged. Replace the upper system board with a new one and test the display again. If the problem still exists, perform Check 7. Check 7 Replace the lower system board with a new one. 2-34 T4850CT...
  • Page 52 Procedure 2 Connector and Replacement Check The status indicator panel is connected to the system board. This cable may be disconnected or damaged. Disassemble the T4850CT as described in Chapter 4 and perform the following checks. Check 1 Make sure the status indicator panel cable is not damaged and is connected to the system board.
  • Page 53 This chapter explains how to use the T4850CT’s Diagnostic Test Program (TEST4850) to test the functions of the computer's hardware modules. The Diagnostics Test Program, stored on the T4850CT Diagnostic Disk, consists of 8 programs that are grouped into the Service Program Module (DIAGNOSTICS MENU) and the Test Program Module (DIAGNOSTICS TEST Menu).
  • Page 54 The following equipment is needed to perform some of the T4850CT’s Diagnostic test pro- grams. The T4850CT Diagnostics Disk (all tests) A formatted working disk for the floppy disk drive test (all tests) 3.5-inch 2HD/2DD disk for the internal 3.5-inch FDD 5.25-inch 2D disk for the external 5.25-inch FDD...
  • Page 55 Executing the Diagnostic Test Toshiba MS-DOS is required to run the T4850CT’s Diagnostics Test Program. To start the Diagnostics Test Program follow these steps. Turn on the computer and allow the computer to boot. Insert the T4850CT Diagnostics Disk in the computer’s internal floppy disk drive.
  • Page 56 04 - Main battery charge 99 - Exit to DIAGNOSTIC TEST menu ↑ ↓ → ← : Select items Enter : Specify : Exit NOTE: The menu displayed by your T4850CT may be slightly different from the one shown above. T4850CT...
  • Page 57 Selecting NO for ERROR STOP keeps the test running even if an error is found. Table 3-1 in Section 3.3 lists the function of each test on the subtest menu. Table 3-3 in Section 3.16 lists the error codes and status for each error. T4850CT...
  • Page 58 320*200 Graphics display 640*200 Graphics display 640*350/400/480 Graphics display Display page “H” pattern display/Border color LCD/DAC pallet TFT color display Status indicator panel Sequential read Sequential read/write Random address/data Write specified address Read specified address PRINTER Ripple pattern Function Wraparound T4850CT...
  • Page 59 Cross talk & peak shift Write/read/compare (CE) Write specified address Read specified address ECC circuit Sequential write W-R-C specified address REAL TIMER Real time Backup memory Real time carry NDP test EXPANSION PCMCIA Wraparound SOUND CODEC (REC/PLAY) SINE wave playback FM Synthesizer T4850CT...
  • Page 60 Table 3-2 Hardware bit status H/W status Reserved — — CPU clock speed 75 MHz 75 MHz Media type FDD type 1.6 MB 2 MB Reserved — — Drive A/B Ext. = A Ext. = B External FDD Internal FDD T4850CT...
  • Page 61 When the read information is higher than the reference data, the display is unchanged. To exit this screen, press the S key. Subtest 04 Main battery charge This subtest executes a quick charge to the main battery. The following message displays during the subtest: [Main battery charge] T4850CT...
  • Page 62 Protected mode This subtest writes constant data and address data to extended memory (maxi- mum address 100000h), then reads new data and compares the results with the original data. The constant data is FFh, AAh, 55h, and 00h. 3-10 T4850CT...
  • Page 63 After selecting subtest 05, the following message will appear: Extended memory size (1:4 MB,2:8 MB,3:16 MB,4:32 MB) ? Select the number that corresponds to the memory card installed in the T4850CT. Subtest 06 Cache memory To test the cache memory, a pass-through write-read comparison of ‘5A’ data is run repeatedly to the test area (‘7000’:’Program’...
  • Page 64 The Keyboard test contains two subtests that test the T4850CT’s keyboard actions, and two subtests that test the mouse connections. Move the highlight bar to the subtest you want to execute and press Enter .
  • Page 65 If the test does not detect an error, it returns to the subtest menu. If it does detect an error, the following message appears: KBC - MOUSE INTERFACE ERROR [[ HALT OPERATION ]] 1: Test end 2: Continue 3: Retry 3-13 T4850CT...
  • Page 66 If the test does not detect an error, it returns to the subtest menu. If it does detect an error, the following message appears: KBC-DCBP INTERFACE ERROR [[ HALT OPERATION ]] 1: Test end 2: Continue 3: Retry 3-14 T4850CT...
  • Page 67 To execute the Display Test, select 4 from the DIAGNOSTIC TEST menu, press Enter and follow the directions displayed on the screen. The Display test contains 12 subtests that test the T4850CT’s display in various modes. Move the highlight bar to the subtest you want to execute and press Enter .
  • Page 68 In this subtest, the character set (addressed 00h to FFh) is displayed in the 40x25 character mode as shown below. Press [Enter] KEY To exit this subtest and return to the DISPLAY TEST menu, press Ctrl + Break . 3-16 T4850CT...
  • Page 69 320*200 GRAPHICS DISPLAY COLOR SET X : [X] GREEN BROWN CYAN MAGENTA WHITE PRESS [Enter] KEY Pressing Enter toggles between the tests. To exit this subtest and return to the DISPLAY TEST menu, press Ctrl + Break . 3-17 T4850CT...
  • Page 70 640*XXX GRAPHICS DISPLAY EVEN DOTS ODD DOTS ALL DOTS DRIVEN DRIVEN DRIVEN PRESS [Enter] KEY Pressing Enter changes the size of the displayed image. To exit this subtest and return to the DISPLAY TEST menu, press Ctrl + Break. 3-18 T4850CT...
  • Page 71 HHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHH Pressing Enter displays the following message: Setting the color CRT (1:yes/2:no) If an external CRT display is connected to the T4850CT, choose 1 to display the following message: [Border color test (7 times press [Enter] key)] Press Enter to execute the border color test. To exit this subtest and return to the DISPLAY TEST menu, press Ctrl + Break .
  • Page 72 After selecting this subtest, the following message will appear and all the icons will be on. [Status Indicator Panel Display] Status Indicator Panel ALL ON PRESS [Enter] KEY After pressing Enter , all icons will be off. Press Enter again to exit. 3-20 T4850CT...
  • Page 73 To execute the Floppy Disk Test, select 5 from the DIAGNOSTIC TEST menu, press Enter and follow the directions displayed on the screen. The Floppy Disk test contains five subtests that test the T4850CT’s internal floppy disk drive. The following messages will appear after selecting the Floppy Disk Test. Answer each ques- tion with an appropriate response to execute the test.
  • Page 74 3 above. The data is then read and compared to the original data. Subtest 04 Write Specified Address This subtest writes specified data to a specified track, head, and address. Subtest 05 Read Specified Address This subtest reads data from a specified track, head, and address. 3-22 T4850CT...
  • Page 75 = XXXXh channel#3 = XXXXh Select the channel number (1-3) ? The printer I/O port address is specified by the XXXXh number. The T4850CT supports three printer channels. Select the printer channel number, and press Enter to execute the selected subtest.
  • Page 76 The printer wraparound con- nector (34M741986G01) wiring diagram is shown in Appendix G. This subtest checks the output and bidirectional modes of the data control and status lines through the printer wraparound connector. 3-24 T4850CT...
  • Page 77 To execute the Async Test, select 7 from the DIAGNOSTIC TEST menu, press Enter and follow the directions displayed on the screen. The Async test contains four subtests that test the T4850CT’s asynchronous communication functions. Move the highlight bar to the subtest you want to execute and press Enter .
  • Page 78 This subtest, used with subtest 02 described above, receives the data from the send side, then sends the received data. Subtest 04 Interrupt Test This subtest checks the Interrupt Request Level of IRQs 4, 3 and 5 from the send side. 3-26 T4850CT...
  • Page 79 CAUTION: The contents of the hard disk will be erased when subtest 02, 03, 04, 05, 06, 08, 09, or 10 is executed. Before running the test, transfer the contents of the hard disk to a backup system. This can be done with the Toshiba MS-DOS BACKUP com- mand.
  • Page 80 • Forward sequential • Reverse sequential • Random Subtest 03 Random Address/Data This subtest writes random data to random addresses on the HDD cylinder, head and sector. The data is then read and compared to the original data. 3-28 T4850CT...
  • Page 81 This subtest writes specified 2-byte data to all of the cylinders on the HDD. Subtest 10 W-R-C specified address This subtest writes data to a specified cylinder and head on the HDD, then reads the data and compares it to the original data. 3-29 T4850CT...
  • Page 82 To execute the Real Timer Test, select 9 from the DIAGNOSTIC TEST menu, press Enter and follow the directions on the screen. The real timer test contains three subtests that test the T4850CT’s real timer functions. Move the highlight bar to the subtest you want to ex- ecute and press Enter .
  • Page 83 Current date : 12-31-1992 Current time : 23:59:58 Pressing Enter displays the following: Current date : 01-01-1993 Current time : 00:00:00 PRESS [Enter] KEY TO EXIT TEST Press Ctrl + Break to exit. 3-31 T4850CT...
  • Page 84 3.13 NDP Test To execute the NDP test, select 10 from the DIAGNOSTIC TEST menu, press Enter and follow the directions on the screen. The NDP test contains one subtest that tests the T4850CT’s NDP (math coprocessor) functions. Subtest 01 NDP test...
  • Page 85 To execute the expansion test, select 11 from the DIAGNOSTIC TEST menu, press Enter and follow the directions on the screen. The expansion test contains one subtest that tests the T4850CT’s expansion port functions. The following message appears after selecting the expansion test.
  • Page 86 3.15 Sound Test To execute the sound test, select 12 from the DIAGNOSTIC TEST menu, press Enter and follow the directions on the screen. The sound test contains three subtests that test the T4850CT’s sound functions. Subtest 01 CODEC (REC/PLAY) Tests the functions of the Codec (AD1848) A/D, D/A converter.
  • Page 87 Record Not Found Media Removed DMA Overrun Error DMA Boundary Error CRC Error FDC Error Seek Error FDD Not Drive Error Time Out Error Write Buffer Error Printer Time Out Fault Select Line Out Of Paper Power Off Busy Line 3-35 T4850CT...
  • Page 88 Control Word Error Status Word Error Bus Error Addition Error Multiply Error PCMCIA Address Line Error REG# Line Error CE#1 Line Error CE#2 Line Error DATA Line Error WAIT Line Error BSY# Line Error BVD1 Line Error No PCMCIA 3-36 T4850CT...
  • Page 89 “1” --- The drive is ready for data transfer. CORR “0” --- Other (Corrected data) “1” --- Correctable data error is corrected. “0” --- Other (Index) “1” --- Index is sensed. “0” --- Other (Error) “1” --- The previous command was terminated with an error. 3-37 T4850CT...
  • Page 90 “1” Illegal command error or a drive status error occurred. TK00 “0” The hard disk found track 0 during a recalibrate command. (Track 0) “1” The hard disk could not find track 0 during a recalibrate command. —— Not used. 3-38 T4850CT...
  • Page 91 CAUTION: The contents of the hard disk will be erased when this program is ex- ecuted. Before executing the function, transfer the contents of the hard disk onto a backup system. This can be done with the Toshiba MS-DOS BACKUP command. See the Toshiba MS-DOS manual for details.
  • Page 92 CAUTION: After the HDD has been formatted, execute the Toshiba MS-DOS FDISK command to partition the HDD. Next, execute the Toshiba MS-DOS FORMAT com- mand. Refer to the Toshiba MS-DOS manual for more information about using these commands. Selecting test 2 in the DIAGNOSTIC MENU and pressing Enter displays the following screen: DIAGNOSTICS - HARD DISK FORMAT : VX.XX...
  • Page 93 After entering the bad tracks, press Enter to execute the format. (e) All track format All tracks are formatted as good tracks except those registered as bad tracks in item (d) above or those identified as bad tracks in track verifi- cation described in item (f) below. 3-41 T4850CT...
  • Page 94 Drive number select (1:#1, 2:#2) ? Bad tracks will be displayed in the format shown below. [[cylinder, head = 0123 03]] Press Enter to return to the Hard Disk Format menu. 3-42 T4850CT...
  • Page 95 Remove the Diagnostics Disk from the FDD, then insert the cleaning disk and press Enter . When the cleaning start message appears, the FDD head cleaning has begun. The display automatically returns to the DIAGNOSTIC MENU when the function is completed. 3-43 T4850CT...
  • Page 96 001 FDD 01 0000 180 00001 00 00 FDD - TIME OUT ERROR Address Error status Pass count HDC status Subtest number Read data Test name Write data Error count Error status name [[1:Next,2:Prev,3:Exit,4:Clear,5:Print,6:FD Log Read,7:FD Log Write]] 3-44 T4850CT...
  • Page 97 The 7 key writes the log information to a floppy disk. In the case of “error retry OK,” a capital “R” will be placed at the beginning of the error status. However, it is not added to the error count. 3-45 T4850CT...
  • Page 98 HDD test (subtests 01 and 05) Real timer test (subtest 02) Printer test (subtest 03) Async test (subtest 01) The system automatically detects the number of floppy disk drives connected to the T4850CT for the FDD test. 3.21.2 Operations CAUTION: Do not forget to load a work disk in the FDD. If a work disk is not loaded, an error will be generated during FDD testing.
  • Page 99 Select Yes or No and press Enter . The following message will appear : Mount the work disk(s) on the drive(s), then press [Enter] key. [Warning : The contents of the disk(s) will be destroyed] This program is executed continuously. To terminate the program, press Ctrl + Break . 3-47 T4850CT...
  • Page 100 FDD and HDD. FORMAT NOTE: This program is only for testing a floppy disk drive. The option is different from the Toshiba MS-DOS FORMAT command. This program can format a 5.25-inch or 3.5-inch floppy disk in the following formats: (a) 2D: Double-sided, double-density, 48/67.5 TPI, MFM mode, 512 bytes, 9 sectors/track.
  • Page 101 (a) When COPY is selected, the following message appears: FLOPPY DISK FORMAT & COPY : VX.XX Type select (0:2DD-2DD,1:2D-2D,2:2D-2HD,3:2HD-2HD) ? (b) Selecting a media/drive type number will display a message similar to the one below: Insert source disk into drive A: Press any key when ready. 3-49 T4850CT...
  • Page 102 —— Max. address —— [Track ] = 0079 [ Head ] = 01 [Sector] = 09 Track number ?? Set the track number you want to dump. The system will access the disk and dump a list. 3-50 T4850CT...
  • Page 103 3.23 System Configuration 3.23.1 Function Description The System Configuration program contains the following configuration information for the T4850CT: BIOS ROM version Boot ROM version The number of math coprocessors KBC version Base memory size The number of floppy disk drives...
  • Page 104 (c) Manual Set of Battery Level POWER ON PASSWORD OTHERS (a) Power-up Mode (b) CPU Cache (c) Speaker Volume (d) Panel Power On/Off (e) Alarm Power On Boot Priority (g) Sound I/O Address (h) Ext. Keyboard “Fn” key equivalent 3-52 T4850CT...
  • Page 105 To make other changes, press N and repeat the steps above. To accept the changes, press Y. NOTE: You can press Esc to quit at any time without saving changes. SETUP asks you to confirm that you don’t want to save your changes. 3-53 T4850CT...
  • Page 106 Display Adapter This option selects either the internal or an external display. VGA Compatible Enables the internal display adapter. Not Used Enables an external display adapter in the Desk Station IV. Additional setup options are not dis- played. 3-54 T4850CT...
  • Page 107 The system starts up by using the internal display if no external display is attached, or by using the external display if one is attached. Simultaneous The system starts up by using both the internal and external displays. 3-55 T4850CT...
  • Page 108 B. FDD B Configures the port for output and input to and from an external 5.25-inch floppy disk drive and assigns the letter B to the external drive. By default the internal drive remains drive A. 3-56 T4850CT...
  • Page 109 Full Power, Economy Power, or Low Power/ Low Power operation. Selecting this option User Setting displays a sub-window of BATTERY SAVE OP- TIONS, like the one shown below. The options in the sub-window cannot be changed and are for informational purposes only. 3-57 T4850CT...
  • Page 110 Processing speed CPU speed High 75MHz 37.5 MHz (Equivalent) Battery save options are described below. CPU Sleep Mode This option enables or disables the CPU sleep function. Enabled Enables sleep mode. Disabled Disables sleep mode. 3-58 T4850CT...
  • Page 111 10, 20, 30, 40, 50 or 60 minutes. Max. LCD Brightness This option selects the LCD’s maximum brightness level. High The LCD’s maximum brightness level is set to high. The LCD’s maximum brightness level is set to low. 3-59 T4850CT...
  • Page 112 Battery Display This option selects which way the status indicator panel indicates the remain- ing battery capacity when the T4850CT is not connected to the AC adapter. The status indicator panel indicates how much battery power is left. Time The status indicator panel indicates an estimated time for which the T4850CT can operate with the remaining battery power.
  • Page 113 Others Whether or not you need to configure the T4850CT with these options depends primarily on the kind of software or peripherals you use. Power-up Mode This option enables or disables the AutoResume feature. You can also set this option using the Hot Key. Disabling AutoResume enables boot mode.
  • Page 114 This option enables or disables the alarm power-on feature. Disabled The alarm power-on feature is disabled. hh:mm:ss The alarm power-on feature is enabled. If you enable this option, the T4850CT will be powered on and boot up, or resume automatically at the time you set here. 3-62 T4850CT...
  • Page 115 HDD → FDD HDD → FDD A → FDD B NOTE: If you turn the T4850CT on while pressing the F10 key, the system attempts to load the operating system in the reverse order that you set by using this option. However, the option setting is not affected by simply pressing the F10 key.
  • Page 116 Left Alt + Left Shift functions as the Fn key. Left Alt + Left Shift Right Alt + Right Shift functions as the Fn key. Right Alt + Right Shift Left Alt + Caps Lock functions as the Fn key. Left Alt + Caps Lock 3-64 T4850CT...
  • Page 117 FRUs need to be removed in order to remove others. Always start by removing the battery pack, then follow the lines on the chart to determine which FRU you must remove next in order to repair the one you think is causing the T4850CT to operate improperly.
  • Page 118 When assembling the T4850CT make sure you use the correct screws to secure the various pieces in place. Screw sizes are listed in the corresponding figures. The T4850CT contains many sharp edges and corners, so be careful not to injure yourself.
  • Page 119 Toshiba. Installation of the wrong battery can cause the battery to explode. After installing an FRU in the T4850CT, confirm that the FRU and the computer are function- ing properly.
  • Page 120 Figure 4-1 Removing the battery pack Installing the Battery Pack NOTE: The battery pack is designed to fit into the T4850CT in only one way. Notice that the battery packs for the T4800CT and T4850CT are different. To install the T4850CT battery pack, follow the steps below and refer to Figure 4-1.
  • Page 121 Optional Memory Card Removing an Optional Memory Card To remove an optional memory card from the T4850CT, follow the steps below and refer to Figures 4-2 and 4-3. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 122 Installing an Optional Memory Card To install an optional memory card in the T4850CT, follow the steps below and refer to Figures 4-3 and 4-2. The top of the optional memory card is marked with the word “insert” and an arrow pointing toward the connecting edge.
  • Page 123 Removing an Optional PCMCIA Card The T4850CT has two PCMCIA slots: one for a card up to 5.0 mm (slot 2) and one for a card up to 16 mm (slot 1). To remove optional PCMCIA cards, follow the steps below and refer to Figures 4-4 through 4-6.
  • Page 124 Figure 4-6 Removing the card from PCMCIA card slot 1 Installing an Optional PCMCIA Card To install an optional PCMCIA card in the T4850CT, follow the steps below and refer to Figures 4-4 through 4-6. To install a PCMCIA card into PCMCIA card slot 2, carefully insert the card, making sure the card is right side up and the contact surface is inserted first (Fig- ure 4-4).
  • Page 125 Hard Disk Drive Removing the Hard Disk Drive To remove the T4850CT’s hard disk drive, follow the steps below and refer to Figures 4-7 through 4-10. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 126 Slide the cover forward slightly (about 2 cm) and lift it off (Figure 4-9). CAUTION: The ground plate is thin, so be careful not to cut yourself when handling it. Figure 4-9 Removing the HDD cover 4-10 T4850CT...
  • Page 127 Figure 4-10 Removing the HDD Installing the HDD To install the T4850CT’s HDD, follow the steps below and refer to Figures 4-10 back through 4-7. Connect the HDD connector to the HDD. Fit the slot on the bottom of the con- nector into the groove on the case and seat the HDD into the case (Figure 4-10).
  • Page 128 Top Cover Removing the Top Cover To remove the T4850CT’s top cover, follow the steps below and refer to Figures 4-11 to 4- Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 129 14 latches are secured (Figure 4-13). Close the display. Secure the four M2.5x6 silver screws at the back of the T4850CT (Figure 4-12). Turn the computer over. Secure the three M2.5x30 screws and one M2.5x12 screw on the bottom of the T4850CT (Figure 4-11).
  • Page 130 Keyboard Removing the Keyboard To remove the T4850CT’s keyboard, follow the steps below and refer to Figure 4-14. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 131 Connect the keyboard cable to pressure plate connector (PJ8) on the upper system board (Figure 4-14). Seat the keyboard in the T4850CT. Note that a fold is built into the keyboard cable. Do not try to bend the cable at any other point when you install the key- board (Figure 4-15).
  • Page 132 Status Indicator Panel Removing the Status Indicator Panel To remove the T4850CT’s status indicator panel, follow the steps below and refer to Figure 4-16. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 133 Let the cable bend naturally when you seat the panel; do not try to fold the cable. Secure the status indicator panel cable with tape. Install the top cover, HDD pack, optional PCMCIA card, optional memory card and battery pack as described in Sections 4.6 back through 4.2. 4-17 T4850CT...
  • Page 134 Backup Battery and Microphone Removing the Backup Battery and Microphone To remove the T4850CT’s backup battery and microphone, follow the steps below and refer to Figure 4-17. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 135 Toshiba. Installation of the wrong battery can cause the battery to explode. To install the T4850CT’s backup battery and microphone, follow the steps below and refer to Figures 4-18 through 4-20. Fit the two notches on the microphone into the two prongs on the computer (Figure 4-18).
  • Page 136 Lay the backup battery and cables in place on the computer and secure them with tape (Figure 4-20). Install the top cover, HDD pack, optional PCMCIA card, optional memory card and battery pack as described in Sections 4.6 back through 4.2. 4-20 T4850CT...
  • Page 137 4.10 Display Assembly Removing the Display Assembly To remove the T4850CT’s display assembly, follow the steps below and refer to Figures 4-21 through 4-24. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 138 Figure 4-22 Removing the display, FL, and ground cables Turn the computer around and remove the two M2.5x6 silver screws on the back of the computer securing the display assembly (Figure 4-23). Figure 4-23 Removing the screws (back of computer) securing the display assembly 4-22 T4850CT...
  • Page 139 (Figure 4-24). Figure 4-24 Removing the display assembly If you are going to disassemble the display assembly, go to Section 4.16. 4-23 T4850CT...
  • Page 140 Connect the panel close switch cable to PJ5 on the upper system board, then secure it with tape (Figure 4-21). Install the top cover, HDD pack, optional PCMCIA card, optional memory card, and battery pack as described in Sections 4.6 back through 4.2. 4-24 T4850CT...
  • Page 141 4.11 Upper System Board and Power Supply Board Removing the Upper System Board and Power Supply Board To remove the T4850CT’s upper system board and power supply board, follow the steps below and refer to Figures 4-25 through 4-27. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 142 Figure 4-26 Removing the upper system board Turn the upper system board over and remove the power supply board (Figure 4-27). Figure 4-27 Removing the power supply board 4-26 T4850CT...
  • Page 143 Installing the Upper System Board and Power Supply Board To install the T4850CT’s upper system board and power supply board, follow the steps below and refer to Figures 4-27 back through 4-25. Connect the power supply board to the upper system board (Figure 4-27).
  • Page 144 4.12 Base Assembly and Power/Reset Board Removing the Base Assembly To remove the T4850CT’s base assembly, follow the steps below and refer to Figures 4-28 through 4-31. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 145 Stand the T4850CT on its back and grasp the computer with your hand covering the base assembly. While holding the computer with one hand to steady it and to protect the base assembly, remove two M2.5x6 silver screws and one M2.5x12 silver screw on the bottom of the computer (Figure 4-29).
  • Page 146 Lift the power/reset board out of the bottom cover (Figure 4-30). Disconnect the power/reset cable from the power/reset board (Figure 4-31). Figure 4-31 Removing the power/reset cable 4-30 T4850CT...
  • Page 147 Installing the Base Assembly To install the T4850CT’s base assembly and power/reset board, follow the steps below and refer to Figures 4-32 back through 4-28. Connect the power/reset cable to the power/reset board (Figure 4-31). Seat the power/reset board inside its brackets on the bottom cover, then fold the power/reset cable down into the slot in front of the system board.
  • Page 148 4.13 Floppy Disk Drive Removing the Floppy Disk Drive To remove the T4850CT’s floppy disk drive, follow the steps below and refer to Figures 4-33 through 4-35. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 149 BPQP port (Figure 4-34). Pull the BPQP port away from the base assembly, but do not disconnect the cable. Figure 4-34 Removing the BPQP port screws Remove the four M2x4 screws securing the FDD and lift the base assembly off the FDD (Figure 4-35). Figure 4-35 Removing the FDD 4-33 T4850CT...
  • Page 150 Installing the Floppy Disk Drive To install the T4850CT’s floppy disk drive, follow the steps below and refer to Figures 4-35 back through 4-33. Place the FDD in the base assembly and, holding the FDD with your hand so it doesn’t fall out, turn the base assembly over.
  • Page 151 4.14 Speaker, RTC Battery and BPQP Port Removing the Speaker, RTC Battery and BPQP Port To remove the T4850CT’s speaker, RTC battery and BPQP port, follow the steps below and refer to Figures 4-34 and 4-36 through 4-38. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord, and all external cables connected to the computer.
  • Page 152 Figure 4-37 Removing the PCMCIA slot 2 connector board Disconnect the speaker, RTC battery, and BPQP port cable from each connec- tor on the PCMCIA slot 2 connector board (Figure 4-38). Figure 4-38 Disconnecting the speaker, RTC battery, and BPQP port cables 4-36 T4850CT...
  • Page 153 Toshiba. Installation of the wrong battery can cause the battery to explode. To install the T4850CT’s speaker, RTC battery, and BPQP port, follow the steps below and refer to Figures 4-38 back through 4-36 and Figure 4-34.
  • Page 154 4.15 Lower System Board Removing the Lower System Board To remove the T4850CT’s lower system board, follow the steps below and refer to Figures 4- 33, and 4-39 through 4-41. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 155 (Figure 4-40). Figure 4-40 Removing the lower system board Turn the lower system board over and disconnect the sound system board from the lower system board (Figure 4-41). Figure 4-41 Removing the sound system board 4-39 T4850CT...
  • Page 156 Installing the Lower System Board To install the T4850CT’s lower system board, follow the steps below and refer to Figures 4- 41 back through 4-39, and 4-33. Connect the sound system board to the lower system board, then turn the board over and place the lower system board on the base assembly frame (Figures 4-41 and 4-40).
  • Page 157 4.16 Display Mask Removing the Display Mask To remove the T4850CT’s display mask, follow the steps below and refer to Figure 4-42. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 158 Secure the cover with two M2.5x6 screws at the top corners. Insert the two rubber cushions at each top corner to cover the screws. Install the top cover and battery pack as described in Sections 4.6 and 4.2. 4-42 T4850CT...
  • Page 159 4.17 FL Inverter Board Removing the FL Inverter Board To remove the T4850CT’s FL inverter board, follow the steps below and refer to Figure 4-43. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 160 Installing the FL Inverter Board To install the T4850CT’s FL inverter board, follow the steps below and refer to Figure 4-43. Connect the FL inverter cable to CN1 on the inverter board and the FL cables to CN2. Route the cables so they are not pinched by the FL inverter board, display hinge or other component.
  • Page 161 4.18 LCD Module Removing the Color LCD Module To remove the T4850CT’s color LCD module, follow the steps below and refer to Figure 4- Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 162 Installing the LCD Module To install the T4850CT’s color LCD module, follow the steps below and refer to Figure 4-44. Connect the three display cables to the LCD connector board. Set the LCD module on edge at the base of the LCD cover and connect the LCD connector board to the LCD module.
  • Page 163 CAUTION: When you remove the FL, be careful not to let any dust or other foreign matter enter the display panel components. To remove the T4850CT’s FL, follow the steps below and refer to Figure 4-45. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 164 Installing the FL To install the T4850CT’s FL, follow the steps below and refer to Figures 4-45 and 4-46. Stand the FL module on edge so the FL side is at the top. Insert the tip of the FL into its slot (Figure 4-46).
  • Page 165 4.20 Display Cable Removing the Display Cable To remove the T4850CT’s display cable, follow the steps below and refer to Figure 4-47. Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 166 Installing the Display Cable To install the T4850CT’s display cable, follow the steps below and refer to Figure 4-47. Fit the display cable to the display cover and secure the display hinge with two M2.5x6 screws. Make sure the display cable wires are placed within the clear insulator in the display cover.
  • Page 167 4.21 Panel Close Switch Removing the Panel Close Switch To remove the T4850CT’s panel close switch, follow the steps below and refer to Figure 4- Turn off the power to the T4850CT, then disconnect the AC adapter, power cord and all external cables connected to the computer.
  • Page 168 4-52 T4850CT...
  • Page 169 LCD cover before securing the module with screws. Do not force the module into place, because stress can affect its performance. Also, the panel’s polarized surface is easily scarred, so be careful when handling it. T4850CT...
  • Page 170 Be sure to quickly wipe off any liquid. Glass is used in the panel, so be careful not to drop it or let it strike a hard object, which could cause breakage or cracks. T4850CT...
  • Page 171 Do not expose the module to direct sunlight or strong ultraviolet rays for long periods. Do not store the module at temperatures below specifications. Cold can cause the liquid crystals to freeze, lose their elasticity or otherwise suffer damage. T4850CT...
  • Page 172 If you transport the module, do not use packing material that contains epoxy resin (amine) or silicon glue (alcohol or oxime). These materials can release gas that can damage the panel’s polarization. NOTE: The T4850CT’s TAB IC on the LCD back panel is easily damaged, so be careful when handling it. T4850CT...
  • Page 173 Appendix B Board Layout Upper System Board Figure B-1 Upper system board (front) T4850CT...
  • Page 174 Figure B-2 Upper system board (back) T4850CT...
  • Page 175 Table B-2 Upper ICs and connectors on the system board (back) Mark Number Name IC4 to IC19 System memory IC20 Video controller (WD90C24A/A2) IC32 Sub LCD controller gate array PJ14 Power supply board connector PJ11 Joint connector 1 PJ12 Joint connector 2 T4850CT...
  • Page 176 Lower System Board Figure B-3 Lower system board (front) T4850CT...
  • Page 177 Figure B-4 Lower system board (back) T4850CT...
  • Page 178 Microphone jack connector PJ316 Headphone jack connector Table B-4 Lower ICs and connectors on the system board (back) Mark Number Name IC300 BIOS ROM IC303 Super integration (T9901) IC314 PCMCIA controller gate array PJ309, PJ310 PCMCIA slot 2 joint connector T4850CT...
  • Page 179 RAS1;001 RAS0;001 MEMWE2;001 — DRMST1;100 DRMST2;100 DRMST3;100 DRMST4;100 — DRMST6;100 DRMST5;100 CAS0;011 DRMST7;100 CAS1;011 DRMST8;100 — CAS2;011 D08;100 CAS3;011 — — D09;100 D24;100 — D25;100 D10;100 D26;100 D11;100 D27;100 D12;100 D28;100 D13;100 D29;100 D14;100 D30;100 D15;100 D31;100 — — T4850CT...
  • Page 180 FR;103 PNEL1;100 STND0;103 — — PNEL0;100 BLUE2;103 — BLUE0;103 RESET;000 BLUE1;103 — — CNTRST;100 STND5;103 XSCLK;103 STND2;103 XCLK;103 LP;103 — — FP;103 STND6;103 LGREN0;103 LGREN1;103 LGREN2;103 RED2;103 — — RED0;103 STND1;103 RED1;103 — STND4;103 STNVCC — — STNVCC — T4850CT...
  • Page 181 LSEG03;110 LSEG10;110 LSEG02;110 LSEG09;110 LSEG01;110 PJ8 KB I/F Connector (19-Pin) Table C-6 KB I/F connector pin assignments (19-pin) Signal Signal KBOT00;010 KBOT03;010 KBRT6;110 KBOT04;010 KBRT0;110 KBOT05;010 KBRT2;110 KBOT06;010 KBRT3;110 KBOT08;010 KBRT1;110 KBOT02;010 KBRT7;110 KBOT07;010 KBRT5;110 KBOT09;010 KBRT4;110 KBOT10;010 KBOT01;010 T4850CT...
  • Page 182 SA12;100 — SA02;100 — SA13;100 IIRDY;100 SA03;100 LA19;100 SA14;100 ALED;100 SA04;100 LA20;100 SA15;100 IIO16;000 SA05;100 SBHE;000 SA16;100 DRVSL;000 SA06;100 LA17;100 SA17;100 LA18;100 IOCHCK;000 SA18;100 CPHLDA;100 SA07;100 EICS16;000 RTCBAT IRQ8;100 SA08;100 EMCS16;000 SA19;100 INTA;000 SA09;100 IRQ13;100 INTR;100 SA10;100 IRQ0;100 SA11;100 T4850CT...
  • Page 183 AGNDIM KBTMG;100 BEEP;000 MASTER;000 KBOT00;000 M12V KEYPRS;100 IMICIN;100 KBOT01;000 — KBOT02;000 IOWR;000 KBOT03;000 IORD;000 KBOT04;000 SPKVOL;100 — EPNLOF;000 KBOT05;000 SPKDRV;000 KBOT06;000 DACK2;000 — RESET;000 MOUSDT;100 DACK3;000 KBOT07;000 IOCLK;100 KBIRQ1;100 DACK0;000 MOUSCK;100 $14R3M;110 EKBDAT;100 AEN;100 EKBCLK;100 CK32K;100 EIORDY;100 $14R7M;100 — T4850CT...
  • Page 184 PSAD7;100 CPCNF;100 PSREQ;000 — — BEEP;000 — DSPV PSAD6;100 PCLR;000 — DSPV PSAD5;100 LOBAT;100 — PSAD4;100 SRBTN;000 — PSAD3;100 — — PSAD2;100 — — DCIN PSAD1;100 ADPCNT;100 DCIN PSAD0;100 CNTRST;100 DCIN PSRW0;000 BRTCNT;100 DCIN PSTMG;000 SPKVOL;100 — SUBBAT M12V T4850CT...
  • Page 185 PJ303 PRT/FDD Connector (for Printer) (25-Pin) Table C-13 PRT/FDD connector (for printer) pin assignments (25-pin) Signal Signal STROB;001 AUTFD;001 PDB00;101 ERROR;001 PDB01;101 PINT;001 PDB02;101 SLIN;001 PDB03;101 — PDB04;101 — PDB05;101 — PDB06;101 — PDB07;101 — ACK;001 — BUSY;102 — PE;101 — SELCT;101 T4850CT...
  • Page 186 PJ304 FDD (Int) Connector (26-Pin) Table C-15 FDD (Int) connector pin assignments (26-pin) Signal Signal ISSEL;000 — — IDIRC;000 IRDAT;000 ILOWD;000 — IMON;000 IWPR;000 IHMED;000 — IRDY;000 ITR0;000 — — DSKCHG;000 IWEN;000 — — IDSL;000 IWDAT;000 — — IINDEX;000 ISTEP;000 — T4850CT...
  • Page 187 SD11;102 — — SA00;100 — SA02;100 SD03;102 — SD12;102 — — HDDCS2;010 — HDDCS1;010 SD02;102 — SD13;102 HDDVCC — — DRVSL;000 — HDDVCC — SD01;102 HDDVCC — SD14;102 HDDVCC — — HDDVCC — — HDDIN;000 SD00;102 ATSEL;100 SD15;102 — T4850CT...
  • Page 188 C.17 PJ306 Serial I/F Connector (9-Pin) Table C-17 Serial I/F connector pin assignments (9-pin) Signal Signal DCD1;101 DSR1;101 RD1;001 RTS1;101 SD1;001 CTS1;101 DTR1;101 RI1;101 — C-10 T4850CT...
  • Page 189 — SD01;101 CPCNF;100 SD02;101 MDMSL;001 SD03;101 $14R7M;100 — MIRQ;001 SD04;101 SPKTON;001 SD05;101 — SD06;101 SA00;101 SD07;101 SA01;101 SMEW;001 SA02;101 SMER;001 SA03;101 — SA04;101 IOWR;001 SA05;101 IORD;001 SA06;101 TC;101 SA07;101 BALE;101 — RESET;101 SA08;101 DACK1;001 SA09;101 IRQ9;101 SA10;101 — C-11 T4850CT...
  • Page 190 LA21;101 ACK;000 LA19;101 BUSY;101 LA20;101 PE;100 DACK6;001 SELCT;100 — AUTFD;000 REFRSH;001 ERROR;000 LA18;101 PINT;000 MASTER;001 SLIN;000 LA17;101 — SBHE;001 SD1;000 IOCHCK;001 DTR1;100 EMCS16;001 RTS1;100 — DCD1;100 EICS16;001 RD1;000 DACK2;001 DSR1;100 DRQ6;101 CTS1;100 DRQ5;101 RI1;100 DACK5;001 — MERD;001 — C-12 T4850CT...
  • Page 191 MCVCCA — MCVP1A — MCVP2A — CADA16;100 CADA22;100 CADA15;100 CADA23;100 CADA12;100 CADA24;100 CADA07;100 CADA25;100 CADA06;100 — CADA05;100 CRSTA;100 CADA04;100 WAITA;000 CADA03;100 INPAKA;000 CADA02;100 REGA;000 CADA01;100 BVDA2;100 CADA00;100 BVDA1;100 CDA00;100 CDA08;100 CDA01;100 CDA09;100 CDA02;100 CDA10;100 WPA;000 CD2A;000 — — C-13 T4850CT...
  • Page 192 REGB;000 CADB16;100 CADB02;100 MCVP1B — BVDB2;100 CADB15;100 CADB01;100 CADB23;100 BVDB1;100 CADB12;100 CADB00;100 CADB24;100 CDB08;100 — — — — CADB25;100 CDB00;100 CADB07;100 CDB09;100 CADB06;100 CDB01;100 CRSTB;100 CDB10;100 CADB05;100 CDB2B;000 CADB04;100 CDB02;100 WAITB;000 WPB;000 INPAKB;000 SPKM;100 — SPKP;100 — RTCBAT C-14 T4850CT...
  • Page 193 MCVCCB — CE2B;000 BSYB;000 IORB;000 MCVCCB — C.22 PJ311 CRT I/F Connector (15-Pin) Table C-22 CRT I/F connector pin assignments (15-pin) Signal Signal RED;101 — LGREN;101 — BLUE;101 — — — — PHSYNC;100 — PVSYNC;100 — — — C-15 T4850CT...
  • Page 194 Table C-25 Microphone jack connector pin assignments (6-pin) Signal Signal AGNDEM AGNDEM EMICIN IMICOF EMICIN N.C. — C.26 PJ316 Headphone Jack Connector (6-Pin) Table C-26 Headphone jack connector pin assignments (6-pin) Signal Signal AGNDHP AGNDHP LHPHON SPKOFF RHPHON N.C. — C-16 T4850CT...
  • Page 195 — CDRQ;100 SD00;100 PDAK;000 SD01;100 CDAK;000 SD02;100 SBEEP;100 SD03;100 IOWR;000 SD04;100 SA00;100 SD05;100 IORD;000 SD06;100 SA01;100 SD07;100 — — — — IMICIN;100 SPKP;100 LHPHON;100 SPKM;100 AGNDIM SDEX;000 RHPHON;100 SDMUTE;100 AGNDHP SDPRDN;000 SPKOFF;100 FMCS;000 EMICIN;100 AD18CS;000 IMICOF;100 AUDINT;100 AGNDEM C-17 T4850CT...
  • Page 196 Appendix D USA Display Codes Table D-1 USA display codes T4850CT...
  • Page 197 Appendix E Keyboard Scan/Character Codes Table E-1 Scan codes (set 1 and set 2) (1/3) Code set 1 Code set 2 Keytop Make Break Make Break Note ‘ ~ 7 & BkSp 29 (42) Caps Lock T4850CT...
  • Page 198 E0 F0 11 E0 F0 70 E0 F0 71 ← E0 F0 6B Home E0 F0 6C E0 F0 69 ↑ E0 F0 75 ↓ E0 F0 72 PgUp E0 F0 7D PgDn E0 F0 7A → E0 F0 74 T4850CT...
  • Page 199 4* Fn key does not generate a code by itself. 5* This key corresponds to key No. 42 in 102-key model. 6* Refer to table D-6, scan codes with Ctrl key. 7* Refer to table D-7, scan codes with Alt key. T4850CT...
  • Page 200 E0 F0 7D E0 F0 12 PgDn E0 2A E0 51 E0 D1 E0 AA E0 12 E0 7A E0 F0 7A E0 F0 12 E0 2A E0 4D E0 CD E0 AA E0 12 E0 74 E0 F0 74 E0 F0 12 → T4850CT...
  • Page 201 E0 2A E0 37 E0 B7 E0 AA E0 12 E0 7C E0 F0 7C E0 F0 12 Ctrl* E0 37 E0 B7 E0 7C E0 F0 7C Shift* E0 37 E0 B7 E0 7C E0 F0 7C Alt* F0 B4 T4850CT...
  • Page 202 Table E-7 Scan codes with Alt key Code set 1 Code set 2 Shift Make Make Pause Common SD C5 F0 77 Ctrl* *: This key generates only make codes. T4850CT...
  • Page 203 Appendix F Key Layout United States (US) Keyboard Figure F-1 US keyboard United Kingdom (UK) Keyboard Figure F-2 UK keyboard T4850CT...
  • Page 204 German (GR) Keyboard Figure F-3 GR keyboard French (FR) Keyboard Figure F-4 FR keyboard T4850CT...
  • Page 205 Spanish (SP) Keyboard Figure F-5 SP keyboard Italian (IT) Keyboard Figure F-6 IT keyboard T4850CT...
  • Page 206 Scandinavian (SC) Keyboard Figure F-7 SC keyboard Swiss-German (SL) Keyboard Figure F-8 SL keyboard T4850CT...
  • Page 207 Canadian (Specialized) Keyboard Figure F-9 Canadian keyboard F.10 Keycap Number Keyboard Figure F-10 Keycap number keyboard T4850CT...
  • Page 208 (4) DTR Figure G-2 RS-232-C wraparound connector RS-232-C Direct Cable (9-Pin to 9-Pin) (3) TD (4) DTR (7) RTS (5) GND (2) RD (1) CD (6) DSR (8) CTS (9) RI Figure G-3 RS-232-C direct cable (9-pin to 9-pin) T4850CT...
  • Page 209 RS-232-C Direct Cable (9-Pin to 25-Pin) (1) CD (2) RD (3) TD (4) DTR (22) (5) GND (7) RTS (6) DSR (20) (8) CTS (9) RI Figure G-4 RS-232-C direct cable (9-pin to 25-pin) T4850CT...
  • Page 210 For security reasons, the Password Deletion Disk will not be distributed to Service Providers. You must obtain the current password from the computer's owner to service the machine. If the owner forgets the password, contact your Toshiba representative for further action. T4850CT...
  • Page 211 This Appendix explains how to rewrite the system BIOS program when updating the BIOS on the T4850CT computer. Tools To rewrite the BIOS, the following tool is required: BIOS rewrite disk for the T4850CT Rewriting the BIOS Set the system to Boot Mode. Turn off the power to the computer.