Toshiba T4500, T4500 Series, T4600 Series, T4500C, T4600 User Manual
...
1.1 Features
The Toshiba T4500/T4600 Family is one of the lightest and most advanced portable computers
available. Utilizing advanced technology and high-speed components, the T4500/T4600 Family
offers excellent display legibility, battery operation and IBM PC/AT compatibility. The T4500/
T4600 Family system unit consists of the following features:
❑ Microprocessor
The T4500 and T4500C uses an i486SX-20 microprocessor that operates at 20 MHz, 3.3
Volts. The T4600 and T4600C uses an i486SL-33 microprocessor that operates at 33 MHz,
3.3 Volts.
❑ Cache memory
The T4500/T4600 Family utilizes an 8 KB cache memory stored in either the i486SX or
i486SL microprocessor.
❑ Disk storage
The T4500 and T4500C have an internal 80, 120, or 200 Megabyte (MB) Hard Disk Drive
(HDD) with an average access time of 19 milliseconds. The T4600 and T4600C have an
internal 120, 200, or 320 MB HDD. A 3.5-inch Floppy Disk Drive (FDD) supports 2HD
floppy disks (1.44 Mbytes) and 2DD floppy disks (720 Kbytes).
❑ Memory
The T4500/T4600 Family comes standard with 4 MB of CMOS Random Access Memory
(RAM) 3.3 Volts. This includes 640 KB of conventional memory and 3,456 KB of extended
memory which can be utilized as expanded memory compatible with the Lotus/Intel/
Microsoft Expanded Memory Specifications (LIM-EMS).
❑ Monochrome LCD (T4500/T4600)
A high-resolution, Liquid Crystal Display (LCD) displays 640 x 480 pixels with a 64-level
gray scale. The T4500 and T4600 internal display controller supports Video Graphics
Adapter (VGA) functions on the internal display device.
❑ TFT color LCD (T4500C/T4600C)
A high-resolution, Thin Film Transistor (TFT) color Liquid Crystal Display (LCD) displays
640 x 480 pixels with 512 colors for both graphics and characters. The T4500C has an 8.4inch TFT color display, and the T4600C has a 9.5-inch TFT color display. The T4500C and
T4600C internal display controller supports Video Graphics Adapter (VGA) functions on
the internal display devices.
❑ Keyboard
An easy-to-use 82/84-key enhanced keyboard with full-size keys and standard spacing is
compatible with IBM standard software.
1-1
❑ Batteries
The T4500/T4600 Family has three different batteries: a main battery, a backup battery,
and a Real Time Clock (RTC) battery.
❑ Expansion port
The T4500/T4600 Family has a unique 150-pin expansion port which attaches to a Desk
Station IV or Desk Station IV Plus.
❑ Personal Computer Memory Card International Association (PCMCIA) card slot
The T4500 and T4500C each have one PCMCIA slot, and the T4600 and T4600C each have
two PCMCIA slots which enable you to install a Toshiba MiNC card modem or other
industry standard PCMCIA card.
❑ Parallel port
The T4500/T4500C’s Centronics-compatible parallel interface port serve two purposes.
The port can be used to connect a Centronics-compatible printer or an external 5.25-inch
floppy disk drive. T4600/T4600C’s port is a parallel interface only and does not support an
external floppy disk drive.
❑ RS-232-C port
The T4500/T4600 Family has one 9-pin serial interface port.
❑ Mouse port
The T4500/T4600 Family has one 6-pin mouse port on the back that can be connected to an
IBM PS/2 mouse.
❑ Keyboard port
The T4500/T4600 Family has one 6-pin keyboard port on the back that can be connected to
an IBM PS/2 keyboard.
❑ Microsoft Ball Point mouse with Quick Port (BPQP) connection
The T4500/T4600 Family has one BPQP port on the right.
❑ RGB port
The T4500/T4600 Family has one 15-pin RGB port on the back that can be connected to an
external video display.
❑ Memory card slot
The T4500/T4600 Family has one Toshiba optional memory card slot which enables you to
install an optional Toshiba memory card.
1-2
The T4500/T4600 Family Personal Computer is shown in Figure 1-1. The T4500/T4500C system
configuration is shown in Figure 1-2, and the T4600/T4600C system configuration is shown in
Figure 1-3.
Figure 1-1 T4500/T4600 Family Personal Computer
Figure 1-2 T4500/T4500C System Unit Configuration
1-3
Figure 1-3 T4600/T4600C System Unit Configuration
1-4
1.2 System Unit Block Diagram
Figure 1-4 is a block diagram of the T4500/T4500C system unit.
Figure 1-4 T4500/T4500C System Board Block Diagram
1-5
The T4500 and T4500C system board shown in Figure 1-4 is composed of the following major
components:
❑ An i486SX-20 CPU
❑ Super Integration (SI) T9901, which stores the following components:
●
Two Direct Memory Access Controllers (DMAC): 82C37
●
Two Programmable Interrupt Controllers (PIC): 82C59
●
One Programmable Interval Timer (PIT): 82C54
●
One Floppy Disk Controller (FDC): TC8565
●
One Serial Input/Output Controller (SIO): TC8570
●
One Variable Frequency Oscillator (VFO): TC8568
●
One I/O Controller
●
One Printer Port Controller
●
One Speaker Controller
❑ A Real Time Clock (RTC)
One T9934 chip is used. The T9934 has 128 bytes of memory. Fourteen bytes of memory
are used for the calendar and clock. The remaining 114 bytes are used for the system
configuration data.
❑ A Keyboard Controller (KBC)
One M37452M4 chip is used. This KBC includes the keyboard scan controller and keyboard interface controller. The KBC controls the internal keyboard, external keyboard port,
PS/2 mouse port, and ball point quick port.
❑ Memory configurations
Standard RAM: 4 MB
Cache memory: 8 KB (inside CPU)
BIOS ROM: 128 KB (96 KB are used)
This Read Only Memory (ROM) contains Initial Reliability Test (IRT),
Basic Input/Output System (BIOS), and video BIOS.
Video RAM: 512 KB
Optional memory cards expand memory to a maximum of 20 MB.
❑ VGA display controller: WD90C26A (144-pin) (3.3 volt operation)
This controller controls internal and external VGA compatible display. It can display the
internal and external display at the same time.
1-6
❑ Clock Generator receives 14.31818 MHz (X1) and generates the following frequencies:
●
20 MHz for the CPU
●
14.7456 MHz for the COM
●
24 MHz for the FDC and VFO
●
16 MHz is used for GA
●
14.31818 MHz for WD90C26A (for VGA)
OSC (X3) generates 32.768 KHz for RTC.
❑ Gate Array
System Controller Gate Array
This gate array has the following functions:
●
Memory Controller
- DRAM Controller
- CPU Controller
- Compatible Bus Interface Controller
●
Bus Controller
- Compatible Bus Interface Controller
- Compatible Access Controller
- DMAC Controller
- I/O Controller
●
Address Latch Controller
- 32-Bit → 16-Bit Controller
- Address Latch
- DMA Address Generator
- Refresh Address Generator
●
I/O Register
- Compatible I/O Port
- Saving the data of the Register (in resume) Controller
- Toshiba Special Register
●
20 MHz/10 MHz Controller
- Data Bus Change Controller
- Data Latch
Sub LCD Controller Gate Array
This gate array has the following functions:
●
Status Indicator Panel Controller
- LCD Segment Flashing Controller
●
Internal Communication Controller
- KBC/Power Supply Micro Processor/Main CPU Communication
Controller
- KBC/Power Supply Micro Processor Interrupt Controller
1-7
IC Card Controller Gate Array
This gate array has 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
- Disable the PRT/FDD Port, HDD Access Controller
- Suspend/Resume Controller
The block diagram of the T4600 and T4600C system board is shown in Figure 1-5.
Figure 1-5 T4600/T4600C System Board Block Diagram
1-8
The T4600 and T4600C system board shown in Figure 1-5 is composed of the following major
components:
❑ An i486SL-33 CPU
❑ One Intel 82360SL
This component is super set with the i486SL microprocessor and stores the following CPU
peripheral components:
●
Two DMACs 8237 equivalent
●
Two PICs 8259 equivalent
●
Two PITs 8254 equivalent (T4600 and T4600C uses one PIT.)
●
Two SIOs 16450 equivalent (T4600 and T4600C uses one SIO.)
●
One RTC MC146818AF equivalent
●
One EPP (Enhanced Parallel Port) controller
❑ One super integration (SI) T9920
The components include the following:
●
One FDC TC8565 equivalent
●
One VFO TC8568 equivalent
●
One speaker controller
❑ A Keyboard Controller (KBC): M37452M4
This KBC includes the keyboard scan controller and keyboard interface controller. The
KBC controls the internal keyboard, external keyboard port, PS/2 mouse port, and ball point
quick port.
❑ The following memories:
Standard RAM: 4 MB
Cache memory: 8 KB (inside CPU)
BIOS ROM: 128 KB (96 KB are used)
This Read Only Memory (ROM) contains Initial Reliability Test (IRT),
Basic Input/Output System (BIOS), and video BIOS.
Video RAM: 512 KB
Optional memory cards expand memory to a maximum of 20 MB.
❑ VGA display controller: WD90C26A (144-pin) (3.3 volt operation)
This controller controls internal and external VGA compatible displays. It can display the
internal and external displays at the same time.
1-9
❑ Clock Generator receives 14.31818 MHz (X1) and generates the following frequencies:
●
66.6 MHz for the CPU
●
14.7456 MHz for the COM
●
24 MHz for the FDC and VFO
●
16 MHz is used for GA
●
14.31818 MHz for WD90C26A (for VGA)
OSC (X3) generates 32.768 KHz for RTC (inside of the 82360SL).
❑ A Power Supply Controller (PSC): TMP90PH48
❑ Gate Array
Sub LCD Controller Gate Array
This gate array has the following functions:
●
Status Indicator Panel Controller
- LCD Segment Flashing Controller
●
Internal Communication Controller
- KBC/Power Supply Micro Processor/Main CPU Communication
Controller
- KBC/Power Supply Micro Processor Interrupt Controller
IC Card Controller Gate Array
This gate array has the following functions:
●
IC Card Controller
- Two cards support PCMCIA Card Controller
- Toshiba Modem Card Controller
●
EEPROM (for security) Controller
- KBC-Security-EEPROM Communication Controller
●
Others
- KBC Communication Controller
- Disable the HDD/FDD/SIO Access Controller
- Suspend/Resume Controller
1-10
1.3 3.5-inch Floppy Disk Drive
The T4500/T4600 Family 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 T4500/T4600 Family FDD is shown in Figure 1-6. The specifications for the FDD are described in Table 1-1.
Figure 1-6 3.5-inch FDD
Table 1-1 3.5-inch FDD Specifications
Item 2-MB mode 1-MB mode
Storage capacity (KB)
Unformatted 2,000 1,000
Formatted 1,311 737
Number of heads 2 2
Number of cylinders 80 80
Access time (ms)
Track to track 3 3
Average 181 181
Head settling time 15 15
Recording track density (tpi) 135 135
Data transfer rate (Kbps) 500 250
Rotation speed (rpm) 300 300
Recording method Modified Frequency Modulation (MFM)
1-11
1.4 2.5-inch Hard Disk Drive
The Hard Disk Drive (HDD) is a random access non-volatile storage device. It has a non-removable 2.5-inch magnetic disk and mini-winchester type magnetic heads.
T4500 and T4500C supports the 80 MB, 120 MB, and 200 MB. T4600 and T4600C supports the
120 MB, 200 MB, and 320 MB.
The T4500/T4600 Family HDD is shown in Figure 1-7. Specifications for the HDD are described
in Table 1-2.
Figure 1-7 2.5-inch HDD
Table 1-2 2.5-inch HDD Specifications
80MB 120 MB 200 MB 320 MB
(CP2084)(MK1422FCV)(CP2124)(MK2124FC)(MK2224FC)(MK2326FC)
Storage capacity (MB)
Formatted 85.4 86.0 121.6 130.1 213.0 340.0
Number of disks 2 1 2 2 2 3
Data heads 4 2 4 4 4 6
Data surfaces 4 2 4 4 4 6
Tracks per surface 1,150 1,501 1,123 1,155 1,560 1,830
Sectors per track 38 (+1) 56 (+1) 53 (+1) 55 (+1) – –
Bytes per sector 512 512 512 512 512 512
Access time (ms)
Track to track 5 3 3 5 3 3
Average 19 15 16 17 12 12
Maximum 40 25 30 36 25 25
Rotation speed (rpm) 3,486 3,600 3,743 3,200 4,000 4,200
Data transfer rate (bps)
To/from media 12 M 17.6 M 18 M 15.3 M 18.9 to 18.7 to
31.6 M 29.6 M
Interleave 1:1 1:1 1:1 1:1 1:1 1:1
Recording method 2-7RLL/ 1-7 RLL 2-7 RLL/ 1-7 RLL 1-7 RLL 1-7 RLL
1-7 RLL 1-7 RLL
1-12
1.5 Keyboard
The 82-(USA) or 84-(European) keyboard is mounted on the T4500/T4600 Family system unit.
The keyboard is connected to the keyboard controller on the system board through a 19-pin flat
cable. The keyboard is shown in Figure 1-8.
See Appendix F for optional keyboard configurations.
Figure 1-8 Keyboard
1-13
1.6 Sidelit Liquid Crystal Display (T4500 & T4600)
The sidelit Liquid Crystal Display (LCD) is composed of an LCD module, a Fluorescent Lamp
(FL), and an FL inverter board.
1.6.1 LCD Module (T4500 & T4600)
The T4500/T4600 sidelit LCD supports 640 x 480 pixels with a High Resolution Graphics Subsystem (HRGS) and 64 levels of gray. The HRGS includes the functions of the Video Graphics
Array (VGA).
The LCD receives vertical and horizontal synchronizing signals, 8-bit data signals (4-bit upper data
signal and 4-bit lower data signal), and shift clock for data transmission. All signals are CMOSlevel compatible.
The sidelit LCD is shown in Figure 1-9 and its specifications are described in Table 1-3.
Table 1-3 Sidelit LCD Specifications
Item Specifications
Number of Dots (dots) 640 x 480
Dot pitch (mm) 0.30 (W) x 0.30 (H)
Display area (mm) 192 (W) x 144 (H)
Contrast 17:1 (typically)
FL current (mA) 5.0
FL frequency (KHz) 42
1-14
Figure 1-9 Sidelit LCD
1.6.2 Fluorescent Lamp (FL) Inverter Board (T4500 & T4600)
The FL inverter board supplies the high frequency current needed to illuminate the FL.
The specifications for the FL inverter board are described in Table 1-4.
Table 1-4 FL Inverter Board Specifications
Item Specifications
Input Voltage (VDC) 10
Power (W) 2.6
Output Voltage (VAC) 1,100
Current (mA) 5.0
Frequency (KHz) 42
Current limits (mA) 2.5 ~ 5.0
1-15
1.7 TFT Color LCD Display (T4500C & T4600C)
The TFT Color Liquid Crystal Display (LCD) contains an LCD module, a Fluorescent Lamp (FL),
and an FL inverter board.
1.7.1 TFT Color LCD Module (T4500C & T4600C)
The T4500C and T4600C TFT color LCD is backlit and supports 640 x 480 pixels with a High
Resolution Graphics Subsystem (HRGS) and 512 colors for graphics and characters. This HRGS
includes the functions of Video Graphics Array (VGA).
The T4500C’s LCD receives vertical and horizontal synchronizing signals, 9-bit data signals, data
enable signals, and shift clock for data transmission. The T4600C’s LCD receives 9-bit data
signals, data enable signals, and shift clock for data transmission. All signals are CMOS-level
compatible.
The TFT LCD is shown in Figure 1-10. The specifications for the LCD are described in Table 1-5.
1-16
Figure 1-10 TFT Color LCD
Table 1-5 TFT Color LCD Specifications
Item T4500C T4600C
Number of Dots (dots) 640 x 480 640 x 480
Dot pitch (mm) 0.267 (W) x 0.27 (H) 0.3 (W) x 0.3 (H)
Display area (mm) 171 (W) x 130 (H) 192 (W) x 144 (H)
Contrast 60:1 (minimum) 60:1 (minimum)
FL current (mA) 5.0 5.0
FL frequency (KHz) 47 47
1.7.2 Fluorescent Lamp (FL) Inverter Board (T4500C & T4600C)
The FL inverter board supplies high frequency current to light the LCD’s Fluorescent Lamp.
The specifications for the FL inverter are described in Table 1-6.
Table 1-6 FL Inverter Board Specifications
Item T4500C T4600C
Input Voltage (VDC) 10 18
Power (W) 6 6
Output Voltage (VAC) 1,100 1,100
Current (mA) 5.0 5.0
Frequency (KHz) 47 47
Current limits (mA) 3.0 to 5.0 3.0 to 5.0
1-17
1.8 Power Supply Board
The power supply board supplies five kinds of voltages to the T4500/T4600 Family system board.
The T4500/T4600 Family power supply board has one microprocessor and it operates at 500 KHz
(power off) or 20 MHz (power on).
The power supply board performs the following functions:
1. Determines if the AC adapter or battery is connected to the computer.
2. Detects DC output and circuit malfunctions.
3. Controls the LED indicator and speaker.
4. Controls the Battery capacity icon, Power on icon and AC adapter icon on the status indicator panel.
5. Turns the battery charging system on and off and detects a fully charged battery.
6. Determines if the power can be turned on and off.
7. Provides more accurate detection of a low battery.
8. Calculates the remaining battery capacity.
The power supply board output rating is specified in Table 1-7.
Table 1-7 Power Supply Board Output Rating
DC Regulation Maximum
Use for Name voltage tolerance current Ripple
(V) (%) (mA) (mV)
System logic, FDD, HDD VCC +5 ±5 2,600 100
RS-232-C, Flash ROM 12V +12 ±5 120 240
Display DSPV +7.5 to +23 – 7W –
RAM, CPU B3V +3.3 ±5 755 66
RS-232-C M12V –7 to –12.6 – 10 –
1-18
1.9 Batteries
The T4500/T4600 Family has three types of batteries:
❑ Main battery pack
❑ Backup battery
❑ Real Time Clock (RTC) battery
Specifications for these batteries are listed in Table 1-8.
Table 1-8 Battery Specifications
Main
Battery
Backup battery Nickel Metal Hydride 1.2 V 1,100 mAH
RTC battery Lithium-Vanadium 3.0 V 50 mAH
Battery name Material Output voltage Capacity
T4500 Nickel Cadmium 9.6 V 2,400 mAH
T4500C, Nickel Metal Hydride 9.6 V 3,000mAH
T4600, T4600C
1.9.1 Main Battery
The removable main battery pack is the computer’s main power source when the AC adapter is not
attached. The main battery recharges the backup battery when the system’s power is on. The
backup and main battery maintain the state of the computer when you enable AutoResume, and
they maintain the information in Hard RAM.
The main battery is shown in Figure 1-11.
Figure 1-11 Main Battery
1-19
Battery Indicator LED
The Battery Indicator LED is located next to the battery pack slot on the front of the T4500/T4600
Family computer and is identified by a battery icon. The indicator shows the status of the removable battery pack, power supply, and AC adapter.
The status of each can be determined by color:
Orange The battery is being charged. (AC adapter is attached.)
Green The battery is fully charged. (AC adapter is attached.)
No light The AC adapter is disconnected from the computer or the AC adapter is attached,
but it cannot charge the battery for one of the following reasons:
❑ The battery is extremely hot. Allow the computer and the battery to reach room
temperature before attempting to charge the battery.
❑ The battery is almost fully discharged. The battery will not begin charging
immediately in this state, it will begin charging a few minutes after the AC
adapter is connected.
Main Battery’s Overload Protective Circuit
The main battery circuit is shown below:
Figure 1-12 Main Battery Circuit (Nickel Cadmium)
1-20
Figure 1-13 Main Battery Circuit (Nickel Metal Hydride)
The T4500/T4600 Family’s main battery has three devices to prevent circuit overload. Table 1-9
shows the overload specifications.
Table 1-9 Circuit Overload Protection Devices for Main Battery
(Nickel Cadmium/Nickel Metal Hydride)
Protection Method Rating/Function
➊ Thermal protector
Electrical rating 12 VDC, 3 A
Maximum circuit breaker current 12 VDC/120 A
Allowable operating temperature 60° ~ 75°
➋ Thermal fuse
Current rating 10 A
Voltage rating 250 V
Temperature rating 91° C
➌ Thermal sensor (Monitors the battery’s temperature)
Load resistance 10 kΩ ±1% (at 25° C)
Operating temperature limits -50° ~ 100° C
➊ Thermal protector
When the temperature falls outside the operating range of 60° to 75° C, the thermal protector reduces the current by increasing the internal resistance.
➋ Thermal Fuses
If the temperature exceeds 91° C, the thermal fuses may blow to protect the battery and the
system.
WARNING: Never try to use a battery unless its fuses are intact. Do not try to replace a
battery fuse or try to bypass a fuse. Using a defective battery can permanently damage the
system and can cause injury.
➌ Thermal sensor
The thermal sensor monitors the temperature of the battery.
➍ T line
The thermal sensor monitors the temperature of the battery and changes the voltage in the T
line accordingly. The power supply microprocessor monitors the voltage changes in the T
1-21
line.
➎ S line
The power supply microprocessor determines the type of battery by whether the S line is
connected to the battery circuit. If the S line is connected to the negative line, the power
supply microprocessor determines that a Nickel Metal Hydride Battery is installed in the
computer. If the S line is not connected, the power supply microprocessor determines that a
Nickel Cadmium Battery is installed in the computer.
1.9.2 Battery Charging Control
Battery charging is controlled by a power supply microprocessor that is mounted on the power
supply. The microprocessor controls whether the charge is on or off and detects a full charge when
the AC adapter and battery are attached to the computer. The system charges the battery using
quick charge or trickle charge.
Quick Battery Charge
When the AC adapter is attached, there are two types of quick charge: quick charge 1 when the
system is powered off, and quick charge 2 when the system is powered on.
Table 1-10 Quick Charge Times
Kind of battery Charging time
Quick charge 1 Nickel Cadmium About 1 hour, 10 minutes
(power off) Nickel Metal Hydride About 1 hour, 30 minutes
Quick charge 2 Nickel Cadmium 1.5 to 4 hours (typical: 2 hours)
(power on) Nickel Metal Hydride 1.5 to 5 hours (typical: 3 hours)
NOTES 1: The time required for quick charge 2 is affected by the amount of power the
system is consuming. Use of the fluorescent lamp and frequent disk access
diverts power and lengthens the charge time.
2: Using quick charge 1, the system CPU automatically stops the charge after
two hours regardless of the condition of the battery.
If one of the following occurs, the battery quick-charge process stops.
1. The battery becomes fully charged
2. The AC adapter or battery is removed.
1-22
3. The battery or output voltage is abnormal.
Data preservation period (full charge) 1 month
Trickle Battery Charge
When the main battery is fully charged and the AC adapter is attached, the microprocessor automatically changes quick charge 1 or 2 to trickle charge.
Detection of full charge
A full charge is detected only when the battery is charging at quick charge. A full charge is detected under any of the following conditions:
1. A battery voltage fall is detected.
2. The charging time exceeds the fixed limit.
3. The thermal rise (+DT) exceeds the fixed limit.
4. The battery’s temperature is over 60°C.
1.9.3 Backup Battery
The backup battery maintains data for AutoResume and Hard RAM. The power source used to
back up the AutoResume or Hard-RAM data is determined according to the following priority:
AC adapter > Main battery > Backup battery
The backup battery is charged by the main battery or AC adapter when the system is powered on.
Table 1-11 shows the charging time and data preservation period of the backup battery.
Table 1-11 Backup Battery Charging/Data Preservation Time
Time
Charging Time Power On 20 H
Power Off Doesn’t charge
Data preservation period (full charge) 8.0 H
1.9.4 RTC battery
The RTC battery provides power to keep the current date, time and other setup information in
memory while the computer is turned off. Table 1-12 shows the charging time and data preservation period of the RTC battery.
Table 1-12 RTC Battery Charging/Data Preservation Time
Charging Time Power On 24 H
Time
Power Off 24 H
1-23
1-24
2.1 T4500/T4600 Family Troubleshooting
Chapter 2 describes how to determine if a Field Replaceable Unit (FRU) in the T4500/T4600
Family is causing the computer to malfunction. The FRUs covered are:
❑ System PCB
❑ Floppy Disk Drive
❑ Hard Disk Drive
❑ Keyboard
❑ Display
❑ Status Indicator Panel
The Diagnostics Disk operations are described in Chapter 3, Tests and Diagnostics and detailed
disassembly and reassembly procedures are given in Chapter 4, Replacement Procedures.
The following tools are necessary for implementing the troubleshooting procedures:
1. A T4500/T4500C Diagnostics Disk or T4600/T4600C Diagnostics Disk
2. A Phillips head screwdriver (2 mm)
3. A Toshiba MS-DOS system disk
4. A 2DD or 2HD formatted work disk for floppy disk drive testing
5. A cleaning kit for floppy disk drive troubleshooting
6. A printer port LED
7. An RS-232-C wraparound connector
8. A printer wraparound connector
9. A multimeter
10. An external 5.25-inch floppy disk drive (only T4500 and T4500C)
11. An external CRT
2-1
2.2 Troubleshooting Flowchart
Use the flowchart in Figure 2-1 as a guide for determining which troubleshooting procedures to
execute. Before going through the flowchart steps, verify the following:
❑ Ask the user if a password is registered, and if it is, ask him or her to enter it. If the user
has forgotten the password, refer to Appendix H for information on password deletion.
❑ Verify with the customer that Toshiba MS-DOS is installed on the hard disk. Non-Toshiba
operating systems can cause the computer to malfunction.
❑ Make sure all optional equipment is disconnected from the computer.
❑ Make sure the floppy disk drive is empty.
2-2
Is the
AC adapter
icon displayed on the Status
Indicator Panel when the AC
adapter is con-
nected?
Perform the Power Supply Troubleshooting
procedures in Section 2.3.
Does
the Battery LED
glow?
Turn the power switch on while
pressing the spacebar.
Is
the P** mes-
sage displayed on the SUB
error message displayed?
LCD?
Is an
Is
the
"MEMORY TEST
XXXKB" message
displayed?
Perform the Power Supply Troubleshooting
procedures in Section 2.3.
Perform the Power Supply Troubleshooting
procedures in Section 2.3.
Perform the System PCB Troubleshooting
procedures in Section 2.4.
Perform the Display Troubleshooting procedures in Section 2.8.
Does
the "MEMORY
TEST XXXKB" message pro-
ceed from 0KB and
640KB?
If the "Password=" message displays,
type the password, then press
Is
Toshiba MS-DOS
being loaded?
Figure 2-1 Troubleshooting Flowchart (1 of 2)
Enter
Perform the System PCB Troubleshooting
procedures in Section 2.4.
.
Perform the Hard Disk Drive Trouble-
shooting procedures in Section 2.6.
2-3
Do typed
characters appear
correctly?
Insert the diagnostics disk into the FDD,
then run the diagnostics test program.
Perform the Keyboard Troubleshooting
procedures in Section 2.7.
Did
the diagnostics
test program load
properly?
Perform each test.
Is
an error
detected by any of the
diagnostic tests?
The system is normal.
Figure 2-1 Troubleshooting Flowchart (2 of 2)
Perform the Floppy Disk Drive Troubleshooting procedures in Section 2.5.
After confirming which diagnostic test has
detected an error, perform the appropriate
procedures as outlined below.
If the diagnostics program cannot detect an error, the problem may be intermittent. The Running
Test program should be executed several times to isolate the problem.
Check the Log Utilities function to confirm which diagnostic test detected an error(s), then perform the appropriate troubleshooting procedures as follows:
1. If an error is detected on the system test, memory test, display test, ASYNC test, printer
test, or real timer test, perform the System PCB Troubleshooting procedures in Section 2.4.
2. If an error is detected on the keyboard test, perform the Keyboard Troubleshooting procedures in Section 2.7.
3. If an error is detected on the floppy disk test, perform the Floppy Disk Drive Troubleshoot-
ing procedures in Section 2.5.
4. If an error is detected on the hard disk test, perform the Hard Disk Drive Troubleshooting
procedures in Section 2.6.
2-4
2.3 Power Supply Troubleshooting
The T4500/T4600 Family’s power supply controls many functions and components. 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:
Procedure 1: Power Status Check on the Status Indicator Panel
Procedure 2: Battery LED Indicator Check
Procedure 3: Battery Power Check
Procedure 4: System PCB Replacement Check
Procedure 1 Power Status Check on the Status Indicator Panel
The Status Indicator Panel displays the status of the following power-related items:
❑ AC adapter or Desk Station IV connection status
❑ System power-on status
❑ Remaining battery power
If an error status is displayed on the Status Indicator Panel, perform Check 1. If the Battery LED
Indicator is flashing red or not glowing, go to Procedure 2. If the three icons listed above are not
displayed, go to Procedure 3.
NOTE: The power supply microprocessor monitors the status of the power supply. When it
detects an error, the error is displayed on the Status Indicator Panel.
Check 1: Read the error status in the battery power indicator area on the Status Indicator Panel.
Table 2-1 Outline of Power Supply Error Status
Status Source of Error
P0* AC Adapter or Desk Station IV error
P1* Battery error
P2* VCC Output error
P3* B3V Output error
P4* 12V Output or M12V Output error
P5* Power Supply Microcomputer error
P6* Power On error
P8* Environment
2-5
❑ Adapter (AC Adapter or Desk Station)
Status Meaning
P01 AC Adapter Voltage is over the maximum allowable limit.
P02 Desk Station Voltage is over the maximum allowable limit.
❑ Battery
Status Meaning
P10 Charge current is over the maximum allowable limit.
❑ VCC Output
Status Meaning
P20 VCC Voltage is over the maximum allowable limit.
P21 VCC Voltage is below the minimum allowable limit.
P22 VCC Voltage is output at a low level (does not fall to zero) while the
power is off.
❑ B3V Output
Status Meaning
P30 B3V Voltage is over the maximum allowable limit.
P31 B3V Voltage is below the minimum allowable limit.
P32 B3V Voltage is not within the normal range while the system is on.
P33 B3V Voltage is not within the normal range while the system is in
the resume mode or Hard-RAM is enabled.
❑ Output Voltage (12V or M12V)
Status Meaning
P40 12V Voltage is over the maximum allowable limit.
P41 12V Voltage is below the minimum allowable limit.
P42 M12V Voltage is not within the normal range
2-6
Loading...