IBM 19K1902 User manual

SERVICE MANUAL
CAUTION
BEFORE SERVICING THE UNIT,
READ THE SAFETY PRECAUTIONS
IN THIS MANUAL.
MODEL: IBM T860 SPEAKER / USB HUB (19K1901)
IBM T860 SPEAKER / USB HUB (19K1902)

1. Audio Specifications
RMS Audio Ootput : 1W+1W(Right+Left)
Input Sensitivity : 0.7Vrms
Speaker Impedance : 4Ω
Distortion : Less than 2% at 50mW output
2. USB Specifications
USB Standard : Rev. 1.1 Compliant BUS-
powered hub
Downstream power supply : 100mA for each(maximum)
Communication speed : 12Mbps(full), 1.5Mbps(low)
USB port :
1Upstream port /
4Downstream ports
3. POWER SUPPLY
Power Input
: DC 12V 0.5A
4. ENVIRONMENT
4-1. Operating Temperature: 10°C~35°C (50°F~95°F)
4-2. Relative Humidity : 10%~80%
(Non-condensing)
5. DIMENSIONS (with TILT/SWIVEL)
Width : 397 mm (15.62'')
Depth : 49.4 mm (1.94'')
Height : 63.5 mm (2.50'')
CONTENTS
SPECIFICATIONS
- 2 -
SPECIFICATIONS ................................................... 2
PRECAUTIONS ....................................................... 3
OPERATING INSTRUCTIONS ................................ 4
BLOCK DIAGRAM ................................................... 7
DESCRIPTION OF BLOCK DIAGRAM.....................8
TROUBLESHOOTING GUIDE ................................ 9
PRINTED CIRCUIT BOARD................................... 13
EXPLODED VIEW...................................................16
REPLACEMENT PARTS LIST ...............................18
PIN CONFIGURATION............................................20
SCHEMATIC DIAGRAM......................................... 21

- 3 -
WARNING FOR THE SAFETY-RELATED COMPONENT.
• There are some special components used in LCD
monitor that are important for safety. These parts are
marked on the schematic diagram and the
replacement parts list. It is essential that these critical
parts should be replaced with the manufacturer’s
specified parts to prevent electric shock, fire or other
hazard.
• Do not modify original design without obtaining written
permission from IBM or you will void the original parts
and labor guarantee.
TAKE CARE DURING HANDLING THE LCD MODULE
WITH BACKLIGHT UNIT.
• Must mount the module using mounting holes arranged
in four corners.
• Do not press on the panel, edge of the frame strongly
or electric shock as this will result in damage to the
screen.
• Do not scratch or press on the panel with any sharp
objects, such as pencil or pen as this may result in
damage to the panel.
• Protect the module from the ESD as it may damage the
electronic circuit (C-MOS).
• Make certain that treatment person’s body are
grounded through wrist band.
• Do not leave the module in high temperature and in
areas of high humidity for a long time.
• The module not be exposed to the direct sunlight.
• Avoid contact with water as it may a short circuit within
the module.
• If the surface of panel become dirty, please wipe it off
with a softmaterial. (Cleaning with a dirty or rough cloth
may damage the panel.)
WARNING
BE CAREFUL ELECTRIC SHOCK !
• If you want to replace with the new backlight (CCFL) or
inverter circuit, must disconnect the AC adapter
because high voltage appears at inverter circuit about
650Vrms.
• Handle with care wires or connectors of the inverter
circuit. If the wires are pressed cause short and may
burn or take fire.
PRECAUTION
CAUTION
Please use only a plastic screwdriver to protect yourself
from shock hazard during service operation.

OPERATING INSTRUCTIONS
- 4 -
DC
12V IN
Rear Control Panel
Side Jacks
Rear Panel Jacks
2. Headphone Jack A headphone jack that
automatically mutes the
speaker volume when
headphones plugged in.
1. Microphone Jack An external microphone
can be used instead of
the preinstalled
microphone.
3. Mic Out - Pink Connects to the
microphone jack of the
computer sound card.
4. Audio In
-Lime Green Connects to the *LINE
OUT jack of the
computer sound card.
4
2
13
Microphone Extension Operation
The Microphone Jacks on the Speaker/USB HUB Option provide a convenient way to extend the microphone input
connector to your desktop.
In order to use the MIC jack on the side of the Speaker/USB HUB Option, use the provided Microphone extender cable
(pink connectors) to plug into the rear of the Speaker/USB HUB Option (MIC OUT) and into the MIC input jack of your
sound card (if available). A microphone (that meets the requirements defined for your sound card) can then be plugged
into the MIC jack on the side of the Speaker/USB HUB Option.
Audio Input
The Audio Input on the back of the Speaker/USB HUB Option should be connected to the Line Output jack on the
computer system sound card using the provided cable (Lime Green connectors). The Speaker/USB HUB Option has a
built-in amplifier (Amp). If the Audio Out of the computer sound card has only Speaker Out, reduce the volume control
on the computer system.
NOTE
If the Audio Out of the computer supports both Speaker Out and Line Out, Please use the Line Out function
(For more information, refer to the documentation that comes with your computer).

- 5 -
USB HUB Jacks External USB 1.1 low power devices such as
keyboards and mouse can be connected to these
ports.
Side Jacks
USB Devices Jack Connects the USB HUB to the computer system
Downstream port.
Rear Jack
Universal Serial Bus (USB) is an innovation that conveniently connects different devices to your computer. USB enables you to
have the flexibility to connect your mouse, keyboard, and other devides to the monitor instead of the computer. The
Speaker/USB HUB Option provides a 4 port USB HUB that will enabel you to connect a chain of up to 120 devices on a single
USB connection. You can “hot-plug” USB devices, that is, you can attach the devices while the computer is on. You can also
disconnect USB devices while maintaining “Plug and Play” auto detection and configuration. This monitor comes with an
integrated BUS-power USB HUB that can have up to four other USB devices attached to it. The Speaker/USB HUB Option has
an integrated BUS-powered HUB that meets the USB 2.0 Specification for Full Speed Devides, allowing up to 4 low power (<100
mA each) USB devices to be attached.
Front Control Panel
1. Power ON/OFF and Volume Control Use to turn on/off audio and used to adjust
volume.
The light-emitting diode (LED) is turned
on for the speaker power ON and is turned
off for the speaker power OFF.
2. Indicator
Control Function
2
1
USB Control Panel

Using the USB (Universal Serial Bus) HUB Featuers
- 6 -
Connecting USB devices
1. Insert the USB cable into the square USB connector of the Speaker/USB HUB Option as shown is the diagram on the left.
Then, insert the other end of the USB cable into the rectangular USB connector on a USB-compliant computer or USB hub as
shown in the diagram on the right.
2. Insert the USB cable for USB-compliant devices into the rectangular USB connector in the monitor as shown in the diagram on
the right.
USB downstream Ports
connect the cables from USB-
compliant peripherals-such as
keyboard, mouse, etc
To USB downstream
port of the USB-
compliant computer or
another hub cable
This is a simplified representation
of the rear view. This is a simplified representation of the side view.
Notes :
To activate the USB hub function, the
Speaker/USB HUB Option must be connected to a USB compliant computer (OS) or
another hub with the USB cable(enclosed).
When connecting the USB cable, check that the shape of the connector at the cable side matches the shape at the connecting
side.
High powered devices (such as stand alone scanners and camera’s etc.) can not be connected to the USB HUB ports. Self
powered devices (use an extermal AC adapter to meet the high power repuirement) can be connected to the USB HUB port.
The USB HUB is compliant to the USB 2.0 Specification and will support low speed and full speed devices (same as USB 1.1).
The HUB can not support high speed devices and will connect them as full speed devices.

- 7 -
U/S
USB
HUB
5V
Reg.
Vari able Resistor
D/S*2
Bus-power USB
1 Up/4 Down
From Main 12V
Audio Amp
TDA7496L
Audio Input Signal
R/L : 700mVrms
DC Volume Control
Power On/Off
LED
Speaker R Out
Speaker L Out
Speaker R
Speaker L
Head Phone R Head Phone L
Mic In
PC
Mic Jack
From PC 5V
D/S*2
From Main 12V
BLOCK DIAGRAM

- 8 -
DESCRIPTION OF BLOCK DIAGRAM
1. USB(Universal Serial Bus) Circuit
This circuit consists of USB hub IC(TUSB2046B), and over voltage protector IC(TPS2042ADR).
This circuit is used to expand four ports of down stream for your easy using of low power device such as
keyboard, mouse and etc.
The integrated Bus-Power USB HUB meets the USB 2.0 specification for Full Speed Devices, allowing
up to 4 low power USB devices to be attached.
2. Audio Circuit
This circuit supports speaker output of 1W+1W(Right, Left).
Main amp(TDA7496L) amplifies input audio signal and has function of volume control, and Shutdown
Volume On/Off/Up/Down Control varies the volume of sound going to the speakers and headphone jack,
and uses to turn on/off audio.
When headphone is plugged into the headphone jack, the speakers are muted, and Microphone input/output
pass through connection to system microphone input.

TROUBLESHOOTING GUIDE
- 9 -
1. AUDIO NO POWER
POWER INDICATOR OFF
TROUBLE IN LED1
TROUBLE BUILT
IN POWER
NO
TROUBLE IN
VR1
TROUBLE
IN U5
NO NO
TROUBLE IN Q1, Q2
NO
YES
YES
YES
YES
CHECK
U5 OUTPUT
(5V) ?
CHECK
VR1?
CHECK
12V DC?
CHECK
Q1,Q2 ?

- 10 -
2. NO VOLUME CONTROL
TROUBLE IN R3, R6, R9
NO
NO
TROUBLE IN VR1
TROUBLE IN U3
YES
YES
CHECK
VR1?
3. AUDIO NO OUTPUT
TROUBLE IN SPEAKER
TROUBLE IN U5
NO
YES
YES
CHECK
U3 OUTPUT
PIN 14, 17 ?
CHECK
U5
(5V)?
TROUBLE
IN U3
NO YES
CHECK
U3 PIN 4, 9
AUDIO IN?
CHECK
J4 AND PC?
TROUBLE
IN U3
NO YES
CHECK
U3 PIN 11, 12
(0V) ?