LG FLATRON 915 FT PLUS User manual

SERVICE MANUAL
LG FLATRON 915FTPLUS
MODEL

1. PICTURE TUBE
Size : 19 inch (Flat Slot Mask)
DefIection Angle : 90°
Neck Diameter : 29.1 mm
Phosphor : P22
Slot Pitch : 0.24 mm
Low Radiation : TCO-99
Face Treatment : AR-ASC coating
2. SIGNAL
2-1. Horizontal & Vertical Sync
1) Input Voltage Level: Low= ≤0.8V, High= ≥2.1V
2) Sync Polarity : Positive or Negative
2-2. Video Input Signal
1) Voltage Level : 0~0.7 Vp-p
a) Color 0, 0 : 0 Vp-p
b) Color 7, 0 : 0.467 Vp-p
c) Color 15, 0 : 0.7 Vp-p
2) Input Impedance : 75 Ω
3) Video Color : R, G, B Analog
4) Signal Format : Refer to the Timing Chart
2-3. Signal Connector
• 15 Pin D-Sub Connector
• 5-BNC Connector
2-4. Scanning Frequency
Horizontal : 30~107 kHz
Vertical : 50~200 Hz
3. POWER SUPPLY
3-1. Power Range
AC 100~120V/200~240V (Auto Select)
50/60Hz, 2.5/1.2A
3-2. Power Consumption
4. DISPLAY AREA
4-1. Active Video Area :
• Max Image Size - 366.0 x 274.5mm (14.40" x 10.80")
• Preset Image Size - 350 x 262 mm (13.78" x 10.31")
4-2. Display Color : Full Colors
4-3. Display Resolution : 1600 Dots x 1200Lines/85Hz
4-4. Video Bandwidth : 235MHz
5. ENVIRONMENT
5-1. Operating Temperature: 10°C~35°C (50°F~95°F)
(Ambient)
5-2. Relative Humidity : 8%~80%
(Non-condensing)
5-3. Altitude : 5000m
6. DIMENSIONS (with TILT/SWIVEL)
Width : 470.0 mm (18.50")
Depth : 470.0 mm (18.50")
Height : 480.0 mm (18.89")
7. WEIGHT (with TILT/SWIVEL)
Net Weight : 26.5 kg (58.40 lbs)
Gross Weight : 28.4 kg (62.70 lbs)
8. USB Specifications
USB Standard :
Rev. 1.0 complied self-powered hub
Downstream power supply : 500mA for each (MAX)
Communication speed : 12 Mbps (Full), 1.5 Mbps (Low)
USB port : 1 Upstream port
4 Downstream ports
SPECIFICATIONS
MODE
NORMAL (ON)
STAND-BY
SUSPEND
OFF
H/V SYNC
ON/ON
OFF/ON
ON/OFF
OFF/OFF
POWER CONSUMPTION
less than 140W
less than 8W
less than 8W
less than 3W
LED COLOR
GREEN
ORANGE
ORANGE

TIMING CHART
VIDEO
SYNC
DA
EF
BC
<< Horizontal Frequency (kHz), Vertical Frequency (Hz), Horizontal etc... (µs), Vertical etc... (ms) >>
1
2
3
4
5
6
7
8
9
10
11
12
H – 31.469 31.778 25.422 6.356 0.640 3.810 1.906
V + 70.082 14.270 12.700 1.557 0.413 0.064 1.08
H – 31.469 31.778 25.422 6.356 0.640 3.810 1.906
V – 59.940 16.683 15.253 1.430 0.318 0.064 1.049
H + 67.500 14.815 10.667 4.148 0.593 1.185 2.370
V + 75.000 13.333 12.800 0.533 0.015 0.044 0.474
H – 49.725 20.111 14.525 5.586 0.559 1.117 3.910
V – 74.550 13.414 12.549 0.865 0.040 0.061 0.764
H + 53.674 18.631 14.222 4.409 0.569 1.138 2.702
V + 85.061 11.756 11.178 0.578 0.019 0.056 0.503
H + 60.023 16.660 13.003 3.657 0.203 1.219 2.235
V + 75.029 13.328 12.795 0.533 0.015 0.044 0.474
H + 68.677 14.561 10.836 3.725 0.508 1.016 2.201
V + 84.997 11.765 11.183 0.582 0.015 0.044 0.523
H – 68.681 14.560 11.520 3.040 0.320 1.280 1.440
V – 75.062 13.322 12.667 0.655 0.044 0.044 0.567
H + 106.250 9.412 6.972 2.441 0.279 0.837 1.325
V + 85.000 11.765 11.294 0.470 0.009 0.028 0.433
H + 79.976 12.504 9.481 3.022 0.119 1.067 1.837
V + 75.025 13.329 12.804 0.525 0.013 0.038 0.475
H + 91.146 10.971 8.127 2.844 0.406 1.016 1.422
V + 85.024 11.761 11.235 0.527 0.011 0.033 0.483
H + 93.750 10.667 7.901 2.765 0.316 0.948 1.501
V + 75.000 13.333 12.800 0.533 0.011 0.032 0.490
720x400
70Hz
640x480
60Hz
1152x864
75Hz
832x624
75Hz
800x600
85Hz
1024x768
75Hz
1024x768
85Hz
1152x870
75Hz
1600x1200
85Hz
1280x1024
75Hz
1280x1024
85Hz
1600x1200
75Hz
Mode
H/V
Sort Sync Polarity
Frequency Total Period
(A) Video Active
Time (B) Blanking Time
(C) Front Porch
(D) Sync Duration (E) Back Porch
(F)
Resolution

CONTROL LOCATIONS
21
3
4
5
6
7
8
9
No.
1
2
3
4
5
No.
6
7
8
9
Ref. No. Ref. No.
VR901
VR2061
Control Function
POWER SWITCH
SET BUTTON
OSD SELECT/ADJUSTMENT (RIGHT)
OSD SELECT/ADJUSTMENT (UP)
OSD SELECT/ADJUSTMENT (DOWN)
Control Function
OSD SELECT/ADJUSTMENT (LEFT)
OSD BUTTON
B+ADJUSTMENT
HIGH-VOLTAGE ADJUSTMENT

WIRING DIAGRAM
P612
P613 P610
P611
P101
P704
P733
P932P931
P701
P904 P903
P306P302
P301
P201
P207
P202
Anode Cap
Tilt
Purity
Purity
CDT Earth
Convergence
DY
Degauss
P319

EXPLODED VIEW
3
4
5
5-1
8-1 818
16
15
17
17
A
D
E
7
6
B
9
13
12 10
14
C
11
2
1
EXPLODED VIEW PARTS LIST
Ref. No.
1
2
3
4
5
5-1
6
7
8
8-1
9
10
11
12
13
14
15
16
17
18
A
B
C
D
E
Part No.
3091TKC037B
2423GG3E41B
6868T19001D
339-002J
4951TKS041A
6140TC2008A
6174Z-1018D
6200TJB004A
4951TKS043A
4810TKM027E
332-102E
4950TKK117A
4951TKS042A
6871TCH079A
4810TKV012A
4815TKT009A
3809TKC021A
332-122B
3550TKK084A
3043TKK048C
6871TVT118A
6871TKT011A
6871TMT125A
6871TCT079A
3313T19009A
Description
CABINET ASSY
CDT SET, M46QDG423X 01N6LD
CDT EARTH
SCREW ASSY, PHP+5x25(FZMW1)+GW18
METAL ASSY, FRAME
DEGAUSSING COIL
FBT(FLY BACK TRANSFORMER), FMMTC61-M1018D
FILTER(CIRC), EMI 03ME3G(3) DELTA
METAL ASSY FRAME
BRACKET FB915B MAIN (“D”-CORE)
SCREW, PTP+4x16(FSWR/FZMY)
METAL, FIX HEAT SINK
METAL ASSY, SHIELD BOTTOM
PWB(PCB) ASSY, COMPOSITE FB915 CONTROL BRAND CA-72 HAND
BRACKET FB915 VOLUME
SHIELD ASSY, TOP
BACK COVER ASSY
SCREW, TP1+M4x16(FZMY1)
COVER SCREW
TILT SWIVEL ASSY
PWB(PCB) ASSY, VIDEO FB915B XKGU BRAND VIDEO TOTAL
PWB(PCB) ASSY, INTERFACE FB915B TOTAL ASSY
PWB(PCB) ASS’Y, MAIN FB915B XKGU BRAND CA-72 TOTAL
PWB(PCB) ASSY, COMPOSITE FB915 CONTROL BRAND CA-72 TOTAL
MAIN TOTAL ASS’Y
Material
Q'ty
1
1
1
4
1
1
1
1
1
1
2
1
1
1
1
1
1
4
2
1
1
1
1
1
1

DISASSEMBLY
(b)
(b)
(a)
(a)
3. TOP SHIELD REMOVAL
1) Remove two screws (a).
2) Remove four screws (b).
3) Remove two screws (c).
4) Remove two screws (d).
5) Remove two screws (e).
6) Slide the Top Shield away from the monitor.
2. BACK COVER REMOVAL
1) Remove two screw covers (a).
2) Remove four screws (b) from the Back
Cover.
3) Slide the Back Cover away from the Front
Cabinet of the monitor.
(a)
(c)
(b)
(b)
(d)
(b)
(d)
(e)
(e)
(a)
(b)
(c)
(a)
(b)
1. TILT/SWIVEL REMOVAL
1) Set the monitor face downward.
2) Remove screw (a).
3) Pressing the latch (b), carefully remove
the Tilt/Swivel by pulling it upward.

(a) (b)
P201
P202
5. VIDEO PCB ASSEMBLY REMOVAL
1) Disconnect P201, P202 and Pin (a) from the
Video PCB.
2) Remove screw (b).
3) Remove the Video PCB Assembly from the
interface Assembly.
(a)
(a)
(a)
(b)
(b)
(a)
(a)
P733
P932
P101-P207
P931
6. INTERFACE & CONTROL PCB ASSEMBLY
REMOVAL
1) Remove five screws (a).
2) Carefully remove the interface Assembly from
the Main PCB Board.
3) Disconnect P101-P207.
4) Remove two screws (b).
5) Remove the control PCB Assembly.
4. TOTAL CHASSIS ASSEMBLY REMOVAL
1) Disconnect P903, P904 (Degaussing pin),
P704 (DY pin), P613 (Tilt pin), P610and
P611, P612 (Purity pin) from the Main PCB.
2) Disconnect P306 (GND Wire) from the
Video PCB.
3) Carefully separate the CDT Board
Assembly from the CDT neck.
4) Discharge the remaining static
electricity by shorting between
the Anode Cap and the CDT ground.
5) Disconnect the Anode Cap
from the CDT.
6) Remove three screws (a).
7) Remove two screws (b).
8) Remove the Total Chassis Assembly
from the Cabinet.

(a)
(a)
(a)
(a)
(a)
(c)
(c)
(d)
(d)
(a)
(b)
(a)
7. MAIN BOARD ASS’Y REMOVAL
1) Remove seven screws (a).
2) Remove screw (b).
3) Remove two screws (c).
4) Remove two screws (d).
5) Remove the Main Bracket and
the Bottom Bracket.
(a)
(a) (a)
(a)
(a)
(b)
(b)
(b)
8. INTERFACE ASSEMBLY REMOVAL
1) Remove five screws (a).
2) Remove the interface Rear Shield.
3) Remove three screws (b).
4) Remove the Interface Front Shield and
Interface PCB.

ADJUSTMENT
GENERAL INFORMATION
All adjustment are thoroughly checked and corrected
when the monitor leaves the factory, but sometimes
several adjustments may be required.
Adjustment should be following procedure and after
warming up for a minimum of 30 minutes.
• Alignment appliances and tools.
- IBM compatible PC.
- Programmable Signal Generator.
(eg. VG-819 made by Astrodesign Co.or equivalent)
- EPROM or EEPROM with saved each mode data.
- Alignment Adaptor and Software.
- Digital Voltmeter.
- White Balance Meter.
- Luminance Meter.
- High-voltage Meter.
AUTOMATIC AND MANUAL DEGAUSSING
The degaussing coil is mounted around the CDT so that
automatic degaussing when turn on the monitor. But a
monitor is moved or faced in a different direction, become
poor color purity cause of CDT magnetized, then press
(DEGAUSSING) on the OSD menu.
ADJUSTMENT PROCEDURE & METHOD
-Install the cable for adjustment such as Figure 1and run
the alignment program on the DOS for IBM compatible PC.
1. Adjustment for B+ Voltage.
1) Display cross hatch pattern at Mode 8.
2) Adjust C951 (+) voltage to 195±0.5V with VR901.
2. Adjustment for High-Voltage.
1) Display cross hatch pattern at Mode 8.
2) Adjust CDT Anode voltage to 27±0.5kV with
VR2061.
3. Adjustment for Factory Mode (Preset Mode).
1) Display cross hatch pattern at Mode 13.
2) Run alignment program for Flatron 915FT(plus),
FB915B on the IBM compatible PC.
3) EEPROM →ALL CLEAR →Y(Yes) command
ÆPower Off ÆPower On.
4) DIST. ADJ. →SIZE-MAX command.
5) Adjust H-SIZE MAX as arrow keys to just of the full
screen size at Mode 13.
6) COMMAND →PRESET START→Y(Yes) command.
7) Adjust tilt as arrow keys to be the best condition.
8) DIST. ADJ. →BALANCE command.
9) Adjust balance of pin balance, key balance as arrow
keys to be the best condition.
10) DIST. ADJ. →FOS. ADJ command.
11) Adjust H-SIZE as arrow keys to 350 ± 2mm.
12) Adjust H-POSITION as arrow keys to center of the
screen.
13) Adjust V-SIZE as arrow keys to 262 ± 1mm.
14) Adjust V-POSITION as arrow keys to center of the
screen.
15) Adjust S-PCC (Side-Pincushion) as arrow keys to
be the best condition.
16) Adjust TRAPEZOID as arrow keys to be the best
condition.
17) Display from Mode 1 to Mode 12 and repeat above
from number 11) to 16).
18) PRESET EXIT →Y (Yes) command.
4. Adjustment for White Balance and Luminance.
1) Set the White Balance Meter.
2) Press the (DEGAUSSING) on the OSD menu for
demagnetization of the CDT.
3) Display color 0,0 pattern at Mode 8.
4) Set Brightness and Contrast to max position.
5) COLOR ADJ. Æ BIAS ADJ. command of the
alignment program.
6) Check whether blue color or not at R-BIAS and G-
BIAS to min position and B-BIAS to 215 (decimal)
position at Sub-Bright to 85 (decimal). If it's not blue
color, the monitor must repair.

Figure 1. Cable Connection
220
Monitor to be
adjusted
IBM
Compatible PC
PARALLEL PORT
Power inlet (required)
Power LED
ST Switch
Power Select Switch
(110V/220V)
Control Line
Not used
RS232C
PARALLEL
V-SYNC POWER
ST
VGS MONITOR
E
V-Sync On/Off Switch
(Switch must be ON.)
F
A
B
C
E
F
A
B
C
1510
5
569
1
1
1
14
13
25
6
5V
5V
5V
4.7K
4.7K
4.7K
74LS06
74LS06
OFF ON
OFF
ON
11
VIDEO
SIGNAL
GENERATOR
7) Adjust Screen control on the FBT to 0.15±0.02FL of
the raster luminance.
8)
Adjust B-BIAS and Sub-Brightness to 155 (decimal).
9) Adjust R-BIAS and G-BIAS command to x=0.283±
0.006 and y=0.298±0.006 on the White Balance
Meter with PC arrow keys.
10) Adjust SUB-Brightness command to 0.5±0.1FL of
the raster luminance.
11) Display color 15,0 box pattern (70x70mm) at Mode 8.
12) DRIVE ADJ command.
13) Set B-DRIVE to 150 (decimal) at DRIVE of the
alignment program.
14) Adjust R-DRIVE and G-DRIVE command to white
balance x=0.283±0.003 and y=0.298±0.003 on the
White Balance Meter with PC arrow keys.
15) Adjust SUB-CONTRAST command to 40±1FL of
the raster luminance.
16) Display color 15,0 full white patten at Mode 8.
17) COLOR ADJ. → LUMINANCE → ABL command.
18) Set the Brightness and Contrast to max position.
19) Adjust ABL to 32±1FL of the luminance.
20) Exit from the program.
5. Adjustment for Focus.
1) Display H character in full screen at Mode 8.
2) Adjust two Focus control on the FBT so that focus
should be the best condition.

TROUBLESHOOTING GUIDE
1. NO POWER
NO POWER
(POWER INDICATOR OFF)
TROUBLE IN
D901
TROUBLE IN
FUSE (F901)
TROUBLE IN
IC901 or Q902
TROUBLE IN
D923, D922, D931,
D924, D925, D927
TROUBLE IN
IC903
CHECK
FUSE OK?
CHECK
C912 (+) VOLTAGE?
(310VDC AT INPUT
VOLTAGE 110VAC)
NO
YES
YES
YES
NO
NO
NO
CHECK
Q902 DRAIN
WAVEFORM (SQUARE
WAVE COMES OUT?)
CHECK
D923, D922, D931,
D924, D925, D927
VOLTAGE?
YES

2. NO CHARACTER
CHECK
IC302 PIN 3, 8,12 (12V),
PIN 17 (5V)?
CHECK
IC302 PIN 2, 6,11 ?
CHECK
IC302 PIN 29, 32, 35 ?
TROUBLE IN
P302,
5V, 12V LINE
TROUBLE IN
PC SIGNAL,
SIGNAL CABLE, IC2001
TROUBLE IN
IC302
TROUBLE IN
CDT SOCKET
NO
YES
NO
NO
YES
YES
CHECK
R, G, B CATHODE
VOLTAGE?
TROUBLE IN
IC303
NO
YES
NO CHARACTER

3. NO RASTER
NO VIDEO
(POWER INDICATOR
GREEN or ORANGE)
CHECK
POWER INDICATOR
GREEN or ORANGE ?
CHECK
SCREEN CONTROL
KNOB OF FBT
CHECK
VOLTAGE AT
D924 CATHODE (195V)
D925 CATHODE (80V)
IC911 OUT (12V)
IC960 CATHODE
(6.3V)?
CHECK
IC271(MICOM) PIN 5
(5V), IC201 PIN 16
(12V)?
ROTATE SCREEN
CONTROL KNOB TO
CLOCKWISE
TROUBLE IN
IC271 (MICOM),
IC201 (T/BASE), TDA4856
TROUBLE IN
SECONDARY CIRCUIT
OF T901, T902
TROUBLE IN PRIMARY
CIRCUIT OF T901, T902
TROUBLE IN
D-SUB & 5-BNC
SIGNAL CABLE
ORANGE
MIN.
(Counter-clockwise)
GREEN
OK
YES
NO
YES
NO

4. NO VERTICAL DEFLECTION
NO V-DEFLECTION
(ONE HORIZONTAL LINE)
CHECK
IC601 PIN 2 (15V) ?
CHECK
IC601 PIN 4
(-12V)?
TROUBLE IN
T901 PIN 18
TROUBLE IN
T901 PIN 17
TROUBLE IN
IC601, VERTICAL
OUTPUT CIRCUIT
NO
NO
YES
YES
CHECK
IC201 PIN 12
(SAWTOOTH WAVE)? TROUBLE IN
IC201
NO
YES

5. TROUBLE IN DPM
CHECK
IC271 (MICOM)
PIN 42, 1 (H/V INPUT)
SIGNAL?
CHECK
IC271 PIN 6, 7
WAVEFORM?
CHECK
IC271 PIN 17
(5V, HIGH)?
CHECK
IC905 PIN 7
(15V) ?
CHECK PC,
(PC IS NOT GOING INTO
DPM MODE)
TROUBLE IN
X201, IC271
TROUBLE IN
IC271
TROUBLE IN
Q903, IC913, D914
TROUBLE IN
T901 or PC
NO H / V SYNC SIGNAL
INPUT H/V SYNC
NO
NO
NO
DPMS TABLE
Mode Item
NORMAL
STAND-BY
SUSPEND
OFF
H / V SYNC
ON / ON
OFF / ON
ON / OFF
OFF / OFF
LED
GREEN
ORANGE
ORANGE
ORANGE
VIDEO
NORMAL
OFF(0V)
OFF(0V)
OFF(0V)
YES
YES
CHECK
B+ LINE
(12V, 15V, 80V,
5V) ?
TROUBLE IN
R938
NO
YES
STAND-BY/SUSPEND/
OFF MODE FAILURE

6. NO DEGAUSSING
CHECK
IC271 PIN 22
(5V)?
CHECK
Q271 COLLECTOR
VOLTAGE
(0.5V)?
CHECK
P903, P904?
CHECK
RL901?
TROUBLE IN
IC271 (MICOM)
TROUBLE IN
Q271
TROUBLE IN
P903, P904
TROUBLE IN
RL901
TROUBLE IN
TH901,
DEGAUSSING COIL
NO DEGAUSSING ( BUTTON MUST BE PRESSED.)
NO
NO
NO
NO
YES
YES
YES
YES

7. NO TILT (ROTATION)
TROUBLE IN P613,
TILT COIL CONNECTOR,
TILT COIL
NO TILT (ROTATION)
TROUBLE IN
IC911, D922
TROUBLE IN
D923, IC613
CHECK
IC612 PIN 12 VOLTAGE
(5V)?
NO
YES
YES
CHECK
IC612 PIN 4
(-12V) ?
NO
TROUBLE IN
IC271 (MICOM), IC704
IC612
YES
CHECK
IC612 PIN 3 ? NO

8. TROUBLE IN OSD
CHECK
IC301 PIN 5
(NEGATIVE H-PULSE
COMES IN ?)
CHECK
IC301 PIN 10
(NEGATIVE V-PULSE
COMES IN?)
CHECK
IC301 PIN 13, 14, 15
(IS THERE ANY SIGNAL
WHEN OPERATING FRONT
CONTROL ?)
NO OSD
TROUBLE IN
IC302
TROUBLE IN
Q301, P302
TROUBLE IN
Q302, P302
TROUBLE IN
IC301, IC271
YES
YES
YES
NO
NO
NO
CHECK
IC301 PIN 4, 9
(5V) ?
TROUBLE IN
P302, D927
NO
YES

BLOCK DIAGRAM