SONY 7335 7345 Service Manual

Sony

Notebook Computer

User Guide

PCG-735/PCG-737

®

Notice to Users

© 1998 Sony Corporation. All rights reserved. This manual and the software described herein, in whole or in part, may not be reproduced, translated, or reduced to any machine-readable form without prior written approval.

SONY CORPORATION PROVIDES NO WARRANTY WITH REGARD TO THIS MANUAL,

THE SOFTWARE, OR OTHER INFORMATION CONTAINED HEREIN AND HEREBY EXPRESSLY DISCLAIMS ANY IMPLIED WARRANTIES OR MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE WITH REGARD TO THIS MANUAL, THE SOFTWARE OR SUCH OTHER INFORMATION. IN NO EVENT SHALL SONY

CORPORATION BE LIABLE FOR ANY INCIDENTAL, CONSEQUENTIAL, OR SPECIAL DAMAGES, WHETHER BASED ON TORT,

CONTRACT, OR OTHERWISE, ARISING OUT OF OR IN CONNECTION WITH THIS MANUAL, THE SOFTWARE, OR OTHER INFORMATION CONTAINED HEREIN OR TO USE THERE.

Sony Corporation reserves the right to make any modification to this manual or the information contained herein at any time without notice. The software described herein is governed by the terms of a separate user license agreement.

Sony and VAIO are registered trademarks of Sony Corporation. Windows and the Windows 98 logo are registered trademarks of Microsoft Corporation.

Intel, MMX, and Pentium are trademarks of Intel Corporation.

All other trademarks are trademarks of their respective owners.

As an ENERGY STAR Partner, Sony has determined that this product meets the ENERGY STAR guidelines for energy efficiency.

Energy Star is an U.S. registered mark.

Safety Information

Owner’s Record

The model number and serial number are located on the bottom of your Sony Notebook Computer. Record the serial number in the space provided here. Refer to the model and serial number when you call your Sony Service Center.

Model Number: PCG-735/PCG-737

Serial Number:________________________

WARNING

Audio and picture distortion may occur if this equipment is positioned in close proximity to any equipment emitting electromagnetic radiation.

To prevent fire or shock hazard, do not expose your Sony Notebook Computer to rain or moisture.

To avoid electrical shock, do not open the cabinet. Refer servicing to qualified personnel only.

Never install modem or telephone wiring during a lightning storm.

Never install telephone jacks in wet locations unless the jack is specifically designed for wet locations

Never touch uninsulated telephone wire or terminals unless the telephone line has been disconnected at the network interface.

Use caution when installing or modifying telephone lines.

Avoid using the modem during an electrical storm.

Do not use the modem or a telephone to report a gas leak in the vicinity of the leak.

Plugable equipment: the socket-outlet shall be installed near the equipment and shall be easy accessible.

Use your notebook only with the supplied AC adapter.

Regulatory Information

This product conforms with the following European Directives: 73/23/EEC (Low Voltage Directive) 89/336/EEC (EMC Directive) 93/68/EEC (CE-Marking Directive)

This equipment complies with EN 55022 Class B and EN 50082-1 for use in following areas: residential, business and lightindustrial.

This equipment has been tested and found to comply with the limits set out in the EMC Directive for using a connection cable shorter than 3 metres (9,8 feet).

The CD-ROM is classified as a CLASS 1 LASER PRODUCT and complies with the Laser Products Safety Standard EN 60825-1. Repair and maintenance only by authorized Sony technicians. Improper repairs can create a safety hazard.

CLASS 1

LASER PRODUCT

TO EN 60825-1

DISPOSAL OF LITHIUM ION BATTERY.

In some areas the disposal of lithium ion batteries in household or business trash may be prohibited. Please use the public collection system.

Dispose of properly at end-of-life.

!Danger of explosion if battery is incorrectly replaced. Replace only with the same or equivalent type recommended by the manufacturer.

!The battery pack used in this device may present a fire or chemical burn hazard if

mistreated. Do not disassemble, heat above 100°C (212°F) or incinerate.

Dispose of used battery promptly.

Keep away from children.

Contents
Welcome
Unpacking Your Notebook Computer .........................................	2
Ergonomic Considerations .............................................................	3
Using Your Notebook Computer
Locating the Controls and Connectors .........................................	5
Connecting a Power Source ...........................................................	8
Starting Your Computer ..............................................................	12
Shutting Down Your Computer ..................................................	13
Registering Windows® 98.............................................................	14
Registering Your Computer .........................................................	15
Using the Keyboard.......................................................................	16
Using the Touchpad ......................................................................	22
Using the Floppy Disk Drive .......................................................	23
Using the CD-ROM Drive ............................................................	26
Using the Headphone with Remote Control .............................	29
Using PC Cards ..............................................................................	32
Using Infrared Communication Devices....................................	34
Using Power Saving Modes .........................................................	36
Using a Second Battery Pack........................................................	38
Using the Weight Saver ................................................................	40
Connecting Peripheral Devices
Connecting a PC card modem .....................................................	42
Connecting the Docking Station ..................................................	44
Connecting a Printer......................................................................	51
Connecting an External Display ..................................................	52
Connecting an External Mouse or Keyboard.............................	55

v

Contents

Connecting External Speakers......................................................	56
Connecting an External Microphone...........................................	57
Connecting a Digital Still Camera
or Other Serial Device....................................................................	58
Connecting a Digital Video Camera Recorder...........................	59
Connecting a Universal Serial Bus (USB) Device ......................	60
Using the Mediabar
Mediabar Functions .......................................................................	62
Customizing Your Notebook Computer
Displaying the Sony Notebook Setup Screen ............................	63
Controlling Power Management..................................................	65
Displaying Battery Information ...................................................	67
Selecting the Display Mode ..........................................................	70
Getting Help
About Sony’s Support Options ...................................................	73
Troubleshooting .............................................................................	75
Using the System and Application
Recovery CD ...................................................................................	79
Notes on Use.............................................................................	83
Adding Memory.............................................................................	88
Index..........................................................................................	91

vi

Welcome

Congratulations on your purchase of the Sony Notebook Computer. Sony has combined leading-edge technology in audio, video, computing, and communications to provide you with state-of-the-art personal computing.

Here are just some of the features your Sony Notebook Computer has to offer (read the details in your About Your Sony Notebook Computer guide).

Exceptional performance –Your PC includes a fast Intel® Pentium® processor with MMX™ technology, a 24x (maximum performance) CD-ROM drive, and a 56 kbps PC card modem.

Portability – The rechargeable battery pack provides two to five hours of use without AC power.

Sony audio and video quality – High-quality, “Sony Tuned” MPEG1 video, which supports full-screen display (12.1-inch Active Matrix LCD screen for the PCG-737 and 12.1-inch Passive Matrix LCD screen for the PCG-735) and enables you to take advantage of today’s advanced multimedia applications, games, and entertainment software.

Multimedia features – Enjoy the stereo speakers or use the supplied headphone to listen to audio and video CDs. The headphone includes a remote control. You can even listen to audio CDs when your computer is in suspend (sleep) mode.

Windows® 98 –Your system includes the latest operating system from Microsoft.

Communications – Access popular online services, send and receive e-mails, browse the Internet, and use the built-in speakerphone, answering machine, and fax features.

Excellent customer support: VAIO Link – If you have some problems with your computer, you can contact VAIO Link by telephone, fax or e-mail (see your Customer Service Guide). Before calling VAIO Link, try to solve the problem by reading your User Guide (troubleshooting chapter) or the manuals and helpfiles of the peripherals or software.

1

Welcome

Unpacking Your Notebook Computer

Remove the following hardware items from the box:

	Rechargeable
Main unit	battery pack	Floppy disk drive	PC card modem

	Weight Saver	Recovery CD	User manuals
CD-ROM drive
(installed)
AC adapter	Power cord	Floppy disk
		drive cable

Phone plug

Headphone

Video cable

Phone cable

You can find the complete list of the items that come with your computer in the About Your Sony Notebook Computer guide.

2

Ergonomic Considerations

Ergonomic Considerations

You will be using your notebook computer as a portable device in a variety of environments. Whenever possible, you should attempt to apply the following ergonomic considerations to both stationary and portable environments.

	Wrists relaxed	Computer positioned
		directly in front of you
	and flat

Arms at desk level

Position of your computer – Place the computer directly in front of you as you work. Keep your forearms horizontal with your wrists in a neutral, comfortable position while using the keyboard, touchpad, or external mouse. Let your upper arms hang naturally at your sides. Take breaks during sessions with your computer. Excessive use of the computer may strain muscles or tendons.

Furniture and posture – Sit in a chair with good back support. Adjust the level of the chair so your feet are flat on the floor. A footrest may make you more comfortable. Sit in a relaxed, upright posture and avoid slouching forward or leaning far backward.

Viewing angle of the computer’s display – Use the display’s tilting feature to find the best position. You can reduce eye strain and muscle fatigue by adjusting the tilt of the display to the proper position.

Adjust the contrast or brightness settings of the display also.

3

Welcome

Lighting – Choose a location where windows and lights do not create glare and reflection on the display. Use indirect lighting to avoid bright spots on the display. You can also purchase accessories for your display that help reduce glare. Proper lighting adds to your comfort and work effectiveness.

Tilt stand – You use the tilt stand to place the computer at an angle that allows comfortable typing.

Placement of an external display – When using an external display, set the display at a comfortable viewing distance. Make sure the display screen is at eye level or slightly lower when you are sitting in front of the monitor.

4

Using Your Notebook Computer

This section describes how to start using your computer and how to use your computer’s internal and external devices, such as the touchpad, floppy disk drive, and CD-ROM drive.

Locating the Controls and Connectors

Front

			1	2	Num	Caps Scroll
					Lock	Lock Lock
	LCD screen (pages 20, 83)		Power indicator (pages 12, 18)
1		7
	Speakers (page 56)		Hard disk drive indicator (page 18)
2		8
	Keyboard (page 16)		Battery 1/2 indicators (pages 18, 67)
3		9
	Touchpad (page 22)		Num Lock indicator (page 19)
4		10
	Left/right button (page 22)		Caps Lock indicator (page 19)
5		11
	Microphone (page 57)		Scroll Lock indicator (page 19)
6		12

5

Using Your Notebook Computer

Left

1	Power switch (page 12)	4	Headphone connector (pages 29, 56)
	Hard disk drive		Microphone connector (page 57)
2		5
	Battery bay (pages 9, 47)		Line In connector
3		6

There is a ventilation slot located directly above the headphone connector. Do not cover the ventilation slot when your computer is on.

All connectors for this notebook are: SELV (Safety Extra Low Voltage), according to EN60950.

6

Locating the Controls and Connectors

Right

1

2

1PC card slots (page 32)

2Multi-purpose bay (page 23)

Back

cover

cover

1				DC In (page 8)			6	Monitor connector (page 52)
2				Serial COM1 connector (page 58)			7	Docking station (page 44)
3	Infrared port (page 34)						8	/	FDD/Printer connector (page 51)
				USB connector (page 60)					Video Out connector (page 54)
4							9
5	/					Mouse/Keyboard connector (page 55)

7

Using Your Notebook Computer

Connecting a Power Source

You can use either AC power or a rechargeable battery pack as a power source.

Using the AC Adapter

1Plug the cable attached to the AC adapter into the DC In connector on the computer.

2Plug one end of the power cord into the AC adapter.

3Plug the other end of the power cord into an AC outlet.

Notebook computer

1	AC adapter
	(supplied)
DC in	2	3
	SELV according to
	EN60950
		Power cord (supplied)
		Hazardous Voltage
		according to EN60950

8

Connecting a Power Source

Using Battery Power

You can use one or two battery packs as a source of power. The second battery pack inserts into the multi-purpose bay on the right side of the computer. (See “Using Power Saving Modes” on page 36.) Additional battery packs are available as a separate option.

The battery pack that comes with your computer is not fully charged at the time of purchase. Follow the steps below to insert and charge the battery pack.

To insert the battery pack

1 Open the cover of the battery bay.

2Insert the battery pack into the battery bay on the left side of the computer.

Battery pack (supplied)

Label side facing down

3 Close the cover of the battery bay.

To charge the battery pack

1Connect the AC adapter to the computer.

2Insert the battery pack if needed.

9

Using Your Notebook Computer

The computer automatically charges the battery (the battery indicator light flashes twice at a slow interval as the battery charges). When the battery is 85% full, the battery indicator light turns off. This process takes approximately two hours. To charge the battery completely, continue charging for an additional hour.

A fully charged battery pack supplies power for approximately 2.5 to 5.5 hours.The time may differ according to the conditions of use.

See “Displaying Detailed Battery Information” on page 68 for information on checking the battery life.

There are two battery indicator lights on the computer:

Battery indicators

1 2

Secondary battery pack (not supplied)

Battery pack (supplied)

	Battery Indicator	Meaning
	1	Indicates the status of the battery pack in the battery
		bay on the left side of the computer.
	2	Indicates the status of the battery pack in the multi-
		purpose bay on the right side of the computer.
	Battery Indicator
	Light Status	Meaning
	On	The computer is using battery power.
	Flashing with the	The battery is running out of power.
	power indicator
	Flashing twice at a The battery is charging.
	slow interval
	Off	The computer is using AC power.

10

Connecting a Power Source

See “Using a Second Battery Pack” on page 38 for information on installing and charging a battery pack in the multi-purpose bay.

Keep the battery pack in the computer while it is directly connected to AC power. The battery pack continues to charge while you are using the computer.

When the remaining battery charge drops to 7%, the computer automatically enters System Hibernation mode. This may result in data loss as the system changes modes.

You can extend battery life by changing the power management modes in the PowerPanel utility. See “Using Power Saving Modes” on page 36.

The battery pack supplied with your computer is a lithium ion battery and can be recharged at any time. Charging a partially discharged battery does not affect battery life.

The battery indicator light is on while you use the battery pack as a power source. When battery life is nearly over, the battery indicator starts flashing.

To remove the battery pack

1Open the cover of the battery bay.

2Pull out the battery pack.

3 Close the cover of the battery bay.

11

Using Your Notebook Computer

Starting Your Computer

1Slide the LCD lock lever in the direction of the arrow, and lift the cover.

LCD lock lever

2Slide the power switch on the left side toward the front of the computer until the power indicator light turns on (green).

Power switch

Power indicator

If you slide the power switch for more than four seconds, the computer turns off.

Note on contrast (PCG-735 only): as the contrast of a LCD is variable, adjust

the contrast as follows:

To increase contrast, press Fn+F6 and then To decrease contrast, press Fn+F6 and then

or or .

12

Shutting Down Your Computer

Shutting Down Your Computer

!To avoid potential loss of data, follow these steps to shut down your computer.

1Click the Start button on the Windows 98 taskbar.

2Click Shut Down at the bottom of the Start menu to display the Shut Down Windows dialog box.

3Select Shut Down.

4Click OK.

Respond to any prompts warning you to save documents.

5Wait for your computer to turn off automatically.

6Turn off any peripherals connected to your computer.

If you are unable to shut down your computer using the steps described above, press the Ctrl+Alt+Delete keys at the same time and select Shut Down in the Task manager window to restart the computer. If you are unable to restart the computer in this way, you can slide the power switch forward and hold for four seconds. This operation may result in data loss.

During a period of inactivity, you can conserve battery life by using system suspend mode. See “Controlling Power Management” on page 65.

13

Using Your Notebook Computer

Registering Windows® 98

The first time you turn on your computer, you need to complete a few steps to register and configure the Windows 98 software that is already installed on your computer.

You must register Windows 98 before you can use the computer.

The on-screen instructions guide you through the registration and configuration process. The following is an overview of the process.

1Gathering information:

Enter your name.

Read and accept the License Agreement.

Enter your Certificate of Authenticity number located on the cover of the Introducing Windows 98 manual.

2Windows 98 setup:

Click the Finish button on the Windows 98 Setup Wizard screen.

3Selecting your computer settings:

If necessary, change the Time Zone, Date and Time on the Date/Time Properties screen.

4Learning about Windows 98:

If you want, take the tour of Windows 98.

14

Registering Your Computer

Registering Your Computer

You can take advantage of Sony’s commitment to quality customer support and receive the following benefits by registering your computer with Sony:

VAIO Link – You can contact VAIO Link by telephone, fax or e-mail (see your Customer Service Guide).

Extended Warranty – Protect your investment. See the Limited Warranty Card for details. See your “Service Guide” for extended warranty conditions.

Follow these steps to use the Sony Notebook Computer’s online registration service.

You must connect your phone line before using any online services, including the online registration service. See “Connecting a PC card modem” on

page 42.

1Enter the information requested on the first online registration form.

2Complete the remaining forms by clicking the Next button each time you complete a form.

3Click the Register Now button to register your computer. Your computer automatically transfers your registration information using your PC card modem and a preset telephone number.

15

Using Your Notebook Computer

Using the Keyboard

Your keyboard is very similar to a desktop computer’s, the keyboard has additional keys that perform specific computer-related tasks.

Escape Key

Function keys

Print Screen key

Shift key

Gr

Ctrl key
Fn key				Applications key
		Alt key
	Windows key			Numeric keypad area

Keys	Descriptions
Numeric keypad	Contains the keys found on a typical calculator.
area	Use the numeric keypad area to type numbers or
	to perform mathematical calculations such as
	addition and subtraction. Note that you must
	press the Num Lock key to activate the numeric
	keypad. (When you do so, the Num Lock light
	will be on.)
Navigation keys	Several keys are devoted to moving the cursor on
	the screen (the four arrow keys which also
	function as the Home, End, Page Up, and Page
	Down keys).
Correction keys	The Insert, Back Space, and Delete keys enable
	you to make corrections in your documents.

16

Using the Keyboard

Keys					Descriptions
Function keys					The twelve function keys along the top of the
					keyboard are used to perform designated tasks.
					For example, in many applications, F1 is the Help
					key. The task associated with each function key
					may vary from one application to the next.
Escape key					The Esc (Escape) key is used to cancel commands
Print Screen key					The Print Screen key takes an electronic snapshot
					of the screen and places it in the Windows
					Clipboard. You can then paste the screen shot into
					a document and print it.
Operator keys					Several keys are always used with at least one
					other key: Ctrl, Alt, and Shift. When held down
					with another key, the Ctrl (Control) and Alt
					(Alternate) keys offer another way to give
					commands. For example, in many applications,
					instead of choosing the Save command from a
					menu, you can hold down Ctrl and press S
					(referred to as Ctrl+S). The Shift key is used to
					produce capital letters or special symbols such as
					@ and $.
Windows key					The key with the Windows logo displays the
					Windows 98 Start menu; it’s the equivalent of
					clicking the Start button on the task bar. See
					“Combinations and Functions with the Windows
					Key” on page 18.
Fn key					The Fn key is used in combination with other keys
					to issue commands. See “Combinations and
					Functions with the Fn Key” on page 20.
Applications key					The Applications key displays a shortcut menu of
					context-sensitive choices; pressing this key is the
					equivalent of clicking the right mouse button.

17

Using Your Notebook Computer

Combinations and Functions with the Windows Key

Combinations				Functions
	+ F1			Displays Windows Help.
	+ Tab			Switches the selected button on the taskbar.
	+ E			Displays Windows Explorer.
	+ F			Displays the Windows Find window to find a
				file or folder. This is the equivalent of selecting
				Find from the Start menu.
	+ Ctrl + F			Displays Find window. This is the equivalent
				of selecting Find from the Start menu.
	+ M			Minimizes all displayed windows.
Shift +			+ M	Returns all minimized windows to their
				previous size.
	+ R			Displays the Run window. This is the
				equivalent of selecting Run from the Start
				menu.
	+ Pause +			Displays the Properties window. This is the
Fn+Break				equivalent of double-clicking the System icon
				in the Control Panel.

Indicators

Indicators				Functions
Power				Lights when the power to the computer is turned
				on. Flashes in system suspend mode.
				Turns off when the computer is in System
				Hibernation mode or powered off.
Hard disk				Lights when data is being read from or written to
				the hard drive. Do not enter system suspend
				mode or turn off the computer when this
				indicator light is on.
Battery 1				Indicates the status of the battery inserted in the
1				battery bay on the left side of the computer.
Battery 2				Indicates the status of the battery inserted in the
2				multi-purpose bay on the right side of the
				computer.

18

Using the Keyboard

Light	On	Off
Num Lock	Turns on when the	Turns off when the
	number keys area in the	alphanumeric character keys
	numeric keypad are	in the keypad area are
	active.	active.
Caps Lock	Turns on when the letters	Turns off when letters
	appear in uppercase as	appear in lower case as you
	you type.	type (unless you hold down
	The Shift key lowers the	the Shift key).
	case of typed letters when
	Caps Lock is on.

Scroll Lock Turns on when the screen scrolls differently. (Exactly how it scrolls depends on the specific application. It has no effect in many applications.)

Turns off when information moves across the display normally.

19

Using Your Notebook Computer

Combinations and Functions with the Fn Key

	Combinations/			Functions
	Feature
	Fn+		(ESC)	Puts the system into system suspend mode, a
				power management state. To return the system
	System suspend
				to the active state, press any key or press the
	mode
				power switch on your computer.
	Fn+		(F2)	Displays the power status, as in the two
				examples below:
	Display power status
				Using AC	Charging
				power	the battery

Fn+ (F3)

Speaker switch

Fn+ (F4) Speaker volume

Fn+ (F5) Brightness control

Fn+ (F6) Contrast control

Fn+ LCD / VGA (F7) Switch to the external display

Fn+

LCD

/

(F8)

Select video out

Toggles the built-in speaker between off and on.

Adjusts the built-in speaker volume.

To increase volume, press Fn+F4, then or .

To decrease volume, press Fn+F4, then

or .

Adjusts the brightness of the LCD.

To increase light intensity, press Fn+F5 and thenor .

To decrease light intensity, press Fn+F5 and thenor .

(For PCG-735) Adjusts the contrast control on the LCD display.

To increase contrast, press Fn+F6, then				or
To decrease contrast, press Fn+F6, then				or .
(For PCG-737) The contrast control is not
currently used on the LCD display.
Toggles between LCD, external display
(connected to the			Monitor connector) and
both LCD and external display.
Only LCD			LCD and external display

Only external display

Toggles between LCD and TV connected to the Video Out connector.

20

Using the Keyboard

Combinations/		Functions
Feature
Fn+	(F9)	Disconnects from the docking station when the

power is on, in case that the charged battery is inserted in the computer.

Fn+ (F12) System hibernation mode

Provides for the lowest level of power consumption. When you execute this command, the state of the system and state of the peripheral devices are written to the hard disk and the system power is turned off. To return the system to the original state, use the power switch to turn on the power.

Fn+E

Eject CD-ROM

Ejects the CD-ROM tray. This command is active only when the CD-ROM tray is in the multipurpose bay; it is inactive when the drive is in the docking station.

	Fn+F	Zooms the display size in or out when the
		display is set to VGA mode.
	Change the display
	size
	Fn+D	Turns off the LCD in order to save power.
	Video standby

Fn+S System idle

Puts the system in idle mode, a power management state. When the system enters idle mode, the hard disk and video enter a low power state, and the CPU clock and the processor are not active.

21

Using Your Notebook Computer

Using the Touchpad

The keyboard contains a cursor-pointing device called a touchpad. You can point to, select, drag, and scroll objects on the screen using the built-in touchpad.

Pointer

	Touchpad			Right button
			Left button
Actions	Descriptions
Point	Slide one finger on the touchpad to place the pointer on an item
	or object.
Single-click	Press the left button once.
Double-click	Press the left button twice.
Right-click	Press the right button once. In many applications, this action
	displays a shortcut menu of context-sensitive choices.
Drag	Slide one finger while pressing the left button. When your
	finger reaches a touchpad edge, the pointer keeps moving until
	you lift your finger. Use this action to select and move objects.
Scroll	Move your finger along the right edge of the touchpad.

See Mouseware Help for information on touchpad features, such as middle button click, adjusting touchpad speed, and Wheel Mouse functions. To access Mouseware Help, double-click the Mouse icon in the Control Panel and click the Help button.

22

Using the Floppy Disk Drive

Using the Floppy Disk Drive

There are two ways to connect the floppy disk drive to your computer:

Externally, by connecting it to the computer’s FDD/Printer connector.

Internally, by inserting it into the multi-purpose bay.

The computer comes with the CD-ROM drive in the multi-purpose bay. If you want to use both the CD-ROM and the floppy disk drive at the same time, use the floppy disk drive as an external drive.

If you connect the floppy disk drive externally while your computer is on, use the Sony Notebook Setup utility to select Floppy Disk Drive. See “Displaying the Sony Notebook Setup Screen” on page 63 for details.

To connect the floppy disk drive externally

Connect the floppy disk drive to the / FDD/Printer connector using the external floppy disk drive cable.

Floppy disk drive (supplied)

to	/	External floppy disk drive cable
FDD/Printer		(supplied)

23