1.For continued safety, do not attempt to modify the
circuit board.
2.Disconnect the AC power and DC Power Jack
before servicing.
1-1-2 Servicing the LCD Monitor
1. When servicing the LCD Monitor Disconnect the
AC line cord from the AC outlet.
2.It is essential that service technicians have an
accurate voltage meter available at all times. Check
the calibration of this meter periodically.
1-1-3 Fire and Shock Hazard
Before returning the monitor to the user, perform the
following safety checks:
1.Inspect each lead dress to make certain that the
leads are not pinched or that hardware is not
lodged between the chassis and other metal parts in
the monitor.
2.Inspect all protective devices such as nonmetallic
control knobs, insulating materials, cabinet backs,
adjustment and compartment covers or shields,
isolation resistor-capacitor networks, mechanical
insulators, etc.
3.Leakage Current Hot Check (Figure 1-1):
WARNING: Do not use an isolation transformer during
this test.
Use a leakage current tester or a metering system
that complies with American National Standards
Institute (ANSI C101.1, Leakage Current for
Appliances), and Underwriters Laboratories (UL
Publication UL1410, 59.7).
Figure 1-1. Leakage Current Test Circuit
4.With the unit completely reassembled, plug the AC
line cord directly into a 120V AC outlet. With the
unit’s AC switch first in the ON position and then
OFF, measure the current between a known earth
ground (metal water pipe, conduit, etc.) and all
exposed metal parts, including: metal cabinets,
screwheads and control shafts. The current
measured should not exceed 0.5 milliamp. Reverse
the power-plug prongs in the AC outlet and repeat
the test.
1-1-4 Product Safety Notices
Some electrical and mechanical parts have special
safety-related characteristics which are often not
evident from visual inspection. The protection they give
may not be obtained by replacing them with
components rated for higher voltage, wattage, etc. Parts
that have special safety characteristics are identified by
on schematics and parts lists. A substitute
replacement that does not have the same safety
characteristics as the recommended replacement part
might create shock, fire and / or other hazards. Product
safety is under review continuously and new
instructions are issued whenever appropriate.
NK15A*/NK17A*1-1
CONFIDENTIAL
1 Precautions
Follow these safety, servicing and ESD precautions to prevent damage and to protect against potential hazards such as
electrical shock.
1-1 Safety Precautions
DEVICE
UNDER
TEST
TEST ALL
EXPOSED METAL
SURFACES
(READING SHOULD
NOT BE ABOVE 0.5mA)
LEAKAGE
CURRENT
TESTER
2-WIRE CORD
ALSO TEST WITH
PLUG REVERSED
(USING AC ADAPTER
PLUG AS REQUIRED)
EARTH
GROUND
!
1-2-1 General Servicing Precautions
1.Always unplug the unit’s AC power cord from the
AC power source and disconnect the DC Power
Jack before attempting to:
(a) remove or reinstall any component or assembly,
(b) disconnect PCB plugs or connectors, (c) connect
a test component in parallel with an electrolytic
capacitor.
2.Some components are raised above the printed
circuit board for safety. An insulation tube or tape
is sometimes used. The internal wiring is
sometimes clamped to prevent contact with
thermally hot components. Reinstall all such
elements to their original position.
3. After servicing, always check that the screws,
components and wiring have been correctly
reinstalled. Make sure that the area around the
serviced part has not been damaged.
1.Immediately before handling any semiconductor
components or assemblies, drain the electrostatic
charge from your body by touching a known earth
ground. Alternatively, wear a discharging wriststrap device. To avoid a shock hazard, be sure to
remove the wrist strap before applying power to
the monitor.
2.After removing an ESD-equipped assembly, place it
on a conductive surface such as aluminum foil to
prevent accumulation of an electrostatic charge.
3.Do not use freon-propelled chemicals. These can
generate electrical charges sufficient to damage
ESDs.
4.Use only a grounded-tip soldering iron to solder or
desolder ESDs.
5.Use only an anti-static solder removal device. Some
solder removal devices not classified as “anti-static”
can generate electrical charges sufficient to damage
ESDs.
4.Check the insulation between the blades of the AC
plug and accessible conductive parts (examples:
metal panels, input terminals and earphone jacks).
5.Insulation Checking Procedure: Disconnect the
power cord from the AC source and turn the power
switch ON. Connect an insulation resistance meter
(500 V) to the blades of the AC plug.
The insulation resistance between each blade of the
AC plug and accessible conductive parts (see
above) should be greater than 1 megohm.
6.Always connect a test instrument’s ground lead to
the instrument chassis ground before connecting
the positive lead; always remove the instrument’s
ground lead last.
6.Do not remove a replacement ESD from its
protective package until you are ready to install it.
Most replacement ESDs are packaged with leads
that are electrically shorted together by conductive
foam, aluminum foil or other conductive materials.
7.Immediately before removing the protective
material from the leads of a replacement ESD,
touch the protective material to the chassis or
circuit assembly into which the device will be
installed.
Caution: Be sure no power is applied to the
chassis or circuit and observe all
other safety precautions.
8.Minimize body motions when handling
unpackaged replacement ESDs. Motions such as
brushing clothes together, or lifting your foot from
a carpeted floor can generate enough static
electricity to damage an ESD.
Some semiconductor (solid state) devices can be easily damaged by static electricity. Such components are commonly
called Electrostatically Sensitive Devices (ESD). Examples of typical ESD devices are integrated circuits and some fieldeffect transistors. The following techniques will reduce the incidence of component damage caused by static electricity.
1-2 Servicing Precautions
WARNING:An electrolytic capacitor installed with the wrong polarity might explode.
Caution:Before servicing units covered by this service manual, read and follow the Safety Precautions
section of this manual.
Note:If unforeseen circumstances create conflict between the following servicing precautions and any of the
safety precautions, always follow the safety precautions.
Level : TTL level
Maximum Pixel Clock rate80 MHz80 MHz
Active Display
Horizontal/Vertical
AC power voltage & Frequency
AC 90 ~ 264 Volts, 60 / 50 Hz ± 3 Hz
Power Consumption50 W (Max)53 W (Max)
Dimensions
Unit (W x D x H)
19.6 x 8.0 x 14.7 Inches (498 x 204.5 x 374 mm)
21.1 x 8.0 x 15.8 Inches (536 x 204.5 x 402 mm)
Carton (W x D x H)
22.5 x 17.4 x 10.6 Inches (571 x 441 x 269 mm)
24.0 x 18.3 x 10.6 Inches (609 x 465 x 269 mm)
Weight 3.95 Kg (8.7 Ibs)4.8 Kg (10.6 Ibs)
Environmental ConsiderationsOperating Temperature : 50 °F ~ 104 °F (10 °C ~ 40 °C)
– MAX Internal speaker Out : Right => 3WRight => 5W
Left => 3WLeft => 5W
Sound Characteristic
– BASS Control Range : -12 dB~ + 12 dB
– TREBLE Control Range : -12 dB~ + 12 dB
– Headphone Out: 5mW max (400m Vrms)
– Output Frequency : RF => 80 Hz ~ 15 kHz
A/V => 80 Hz ~ 15 kHz
NK15A*/NK17A*2-1
Item
Description
NK15A*NK17A*
334.08 mm / 200.44 mm370.560 mm / 222.336 mm
TunningFrequency Synthesize
SystemPAL, SECAM, NTSC 4.4
SoundBG, DK, I, L, L’
CVBS
Audio L
GND
Audio R
GND
CONFIDENTIAL
2 Product Specifications
2-2NK15A*/NK17A*
2-2 Pin Assignments
Pin
Separate
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
Red
Green
Blue
GND
GND (DDC Return)
GND-Red
GND-Green
GND-Blue
No Connection
GND-Sync./Self Test
GND
DDC Data
H-Sync.
V-Sync.
DDC Clock
Pin
Separate
1
2
3
4
5
GND
Y
C
GND
GND
2-2-1 D-SUB
2-2-3 S-Video
2-2-2 SCART1, SCART2
RCA White
RCA Red
2-2-4 A/V
RCA Yellow
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
ItemsScart1Scart2
Pin
No
Audio Out (R;500mV/1KΩ)
Audio IN (R;500mV/10KΩ)
Audio Out (L;500mV/1KΩ)
Audio Common GND
Blue GND
Audio IN (L;500mV/10K)
Blue IN (700mV/75Ω)
Function S/W
(0~2V/9, 5V~12V)
Green GND
No Connection
Green IN (700mV/75Ω)
No connection
Red GND
F/B GND
Red IN (700mV/75Ω)
RGB F/B (0~0, 4V/1~3V)
Video Output GND
Video Input GND
CVBS Out (1V/75Ω)
CVBS IN (1V/75Ω)
Common GND
OO
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
O
CONFIDENTIAL
2 Product Specifications
NK15A*/NK17A*2-3
2-3 Timing Chart
This section of the service manual describes the timing that the computer industry recognizes as standard
for computer-generated video signals.
µs
µs
µs
µs
µs
µs
µs
µs
2-3-1 LCD Panel Mode : 1 mode
CONFIDENTIAL
2 Product Specifications
2-4NK15A*/NK17A*
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
2-3-2 Supported Modes (1)
CONFIDENTIAL
2 Product Specifications
NK15A*/NK17A*2-5
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
2-3-2 Supported Modes (2)
CONFIDENTIAL
2 Product Specifications
2-6NK15A*/NK17A*
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
µs
2-3-2 Supported Modes (3)
3-1 General Alignment Instuction
1. Usually, a color TV-VCR needs only slight
touch-up adjustment upon installation.
Check the basic characteristics such as height,
horizontal and vertical sync.
2. Use the specified test equipment or its
equivalent.
3. Correct impedance matching is essential.
4. Avoid overload. Excessive signal from a
sweep generator might overload the front-end
of the TV. When inserting signal markers,
do not allow the marker generator to distort
test result.
5. Connect the TV only to an DC power source
with voltage and frequency as specified on
the backcover nameplate.
6. Do not attempt to connect or disconnect any
wire while the TV is turned on. Make sure
that the power cord is disconnected before
replacing any parts.
7. To protect aganist shock hazard,use an
isolation transform.
NK15A*/NK17A*3-1
CONFIDENTIAL
3 Disassembly and Reassembly
This section of the service manual describes the disassembly and reassembly procedures for the
NK15A*/NK17A* monitor.
WARNING: This monitor contains electrostatically sensitive devices. Use caution when handling
these components.
3-1 Disassembly
Cautions:1. Disconnect the monitor from the power source before disassembly.
2. Follow these directions carefully; never use metal instruments to pry apart the cabinet.
1. After confirm there is nothing
on the desk
Turn the LCD module over
and put it on a flat desk set to
the ground.
3-2 Replacement Order of Lamp Assemblies
CONFIDENTIAL
3 Disassembly and Reassembly
3-2NK15A*/NK17A*
2. Push down the stopper and
slide the lamp unit.
3. Please take out the lamp
units from the LCD module.
4. Please fix the new lamp
units on the LCD module :
opposite process 2 and 3
3-3 Reassembly
Reassembly procedures are in the reverse order of Disassembly procedures.
* Replacement of lamp unit should be done at the power off state and recommended clean bench
condition.
CONFIDENTIAL
NK15A*/NK17A*4-1
4 Alignments and Adjustments
4-1 General Alignment Instuction
1. Usually, a color TV-VCR needs only slight touch-up adjustment upon installation.
Check the basic characteristics such as height, horizontal and vertical sync.
2. Use the specified test equipment or its equivalent.
3. Correct impedance matching is essential.
4. Avoid overload. Excessive signal from a sweep generator might overload the front-end
of the TV. When inserting signal markers,do not allow the marker generator to distort
test result.
5. Connect the TV only to an DC power source with voltage and frequency as specified on
the backcover nameplate.
6. Do not attempt to connect or disconnect any wire while the TV is turned on. Make sure
that the power cord is disconnected before replacing any parts.
7. To protect aganist shock hazard,use an isolation transform.
4 Alignments and Adjustments
4-2NK15A*/NK17A*
CONFIDENTIAL
4-2 Factory Mode Adjustments
4-2-1 Entering Factory Mode
1. To enter “Service Mode” Press the remote - control keys in this sequence :
- If you do not have Factory remote - control
- If you have Factory remote - control
4-2-2 Factory Mode Tree
4 Alignments and Adjustments
NK15A*/NK17A*4-3
CONFIDENTIAL
Memo
4 Alignments and Adjustments
4-4NK15A*/NK17A*
CONFIDENTIAL
CONFIDENTIAL
NK15A*/NK17A*5-1
5 Troubleshooting
5-1 No Power
Does proper DC 14V appear at DC
jack connected to CN801?
Check SMPS PCB and Adapter.
Yes
No
No
No
No
No
Does proper DC 3.3V_A
appear at FT852?
Check IC801. (#2)
Yes
Does proper DC 2.5V_A
appear at Pin 3 of IC802?
Check IC802.
Yes
Does proper DC 3.3V_B
appear at FT822?
Check IC805. (#1)
Yes
Does proper DC 2.5V_B
appear at Pin 3 of IC806?
Check IC806.
WAVEFORMS
IC801 #2
1
IC805 #1
2
1
2
CONFIDENTIAL
5 Troubleshooting
5-2NK15A*/NK17A*
5-2 No Video (PC Signal)
Power indicator is green.
Does the signal appear
at C306, C398, C397
of R, G, B input?
Check CN401 and cable.
Yes
No
No
No
No
No
Yes
Yes
Yes
Yes
Yes
Does the clock pulse appear at
output of RA351 ~ RA356?
Check related circuit of IC350.
Does the clock pulse
appear at R354?
Check R354 and related
circuit of R354.
Does the clock pulse
appear at X201?
Check X201 and related
circuit of X201.
Does the clock pulse appear at
output of RA301~RA306?
Replace RA301 ~ RA306, IC300.
Replace LCD Panel.
WAVEFORMS
Full White R, G, B Input (C306, 398, 397)3X201
4
3
4
CONFIDENTIAL
5 Troubleshooting
NK15A*/NK17A*5-3
5-3 No Picture (TV, Video, S-Video, SCART)
Check the CO44, CO45(S-Video),
CO46(VCR) and CO42(RF-CVBS).