Tovis MTG-2907TN Manual de usuario
MTG-2907TN Publication A. Issue 1
SERVICE AND OPERATION MANUAL
MTG-2907TN : 29INCH, FST
Information in this publication current as of Jun, 2003.
Information subject to change as display technology advance.
This publication produced by TOVIS Engineering Division.
This monitor has been designed and manufactured to deliver high performance video. For continued peak Performance
use safe operation, only high quality TOVIS replacement parts or their exact specified Equivalent When servicing.
MTG- 2907TN
OPEN FRAME VGA COLOR MONITORS
2
SAFETY PRECAUTIONS AND WARNINGS
Service Warning
This display contains HIGH VOLTAGE capable
of delivering LETHAL quantities of energy.
Service should only be attempted by trained
personnel familiar with the potential dangers
inherent with voltage equipment.
Safety Related Component Warning
Certain components used in TOVIS color
monitors are critical for safe operation of the
display. These parts Number are marked by
( ) in the parts list and on the schematic
diagram it is essential that these Safety critical
components be replaced only with exactly
specified components to prevent the
Possibility of excessive X-radiation emission,
electrical shock, fire, or premature
component failure.
Modifying the original design without written
approval from TOVIS is expressly forbidden, will
void the original Parts and labor warranty, and
may result in creating a hazardous situation.
X-RADIATION WARNING
COMPONENTS WHICH MAY AFFECT POTENTIAL
EXCESS EMISSION OF X-RADIATION IN THE
HORIZONTAL DEFLECTION AND HIGH VOLTAGE
CIRCUITS (INCLUDING THE PICTURE TUBE) ARE
TO BE USE ONLY TYPE AND RATING OF
REPLACEMENT COMPONENT AS SHOWN IN THE
PARTS LIST.
1. The only potential source of X-radiation
emission is the picture tube. When the high
voltage and horizontal deflection circuits are
operating correctly there is no possibility of
excess X- radiation emission. NEVER attempt
to modify these circuits.
2. Periodically check the high voltage with a
reliably calibrated meter for values not in
excess of Manufacturer’s recommendations.
See high voltage Shut-down Circuit, page 4,
for further details.
CRT Warning
All picture tubes used in TOVIS monitors are
equipped with an integral implosion protection
system.
The picture Tube is, however, a highly evacuated
component whose outside surfaces are subject to
strong external forces. Care must be exercised so
as not to bump or scratch the tube during
installation or servicing as this may cause the tube
to implode resulting in possible personal injury and
property damage. Shatter-proof goggles must be
worn by Individuals while handling the CRT or
installing the display in the cabinet. Do not handle
The CRT by the neck.
1. Always ensure the high voltage at the anode cap
is fully discharged prior to handling or service.
2. Replace picture tube only with same type and
number.
Product Safety and Service Guidelines
1. Service should be performed only after reading all
of the warnings and precautions in this manual
and as Labeled on the CRT and chassis.
2. Where a short circuit has occurred, replace all
components that indicate evidence of
overheating or poor Connection on all plastic
connectors.
3. Inspect wiring for frayed leads and damaged
insulation when service is required, observe original
lead Dress is followed as from the factory,
especially in the high voltage circuitry area.
4. All protective devices must be reinstalled per
original design.
3
PERFORMANCE AND OPERATING DATA
1. Power Supply
*Power Input: Auto-Doubler
90VAC ~ 132VAC, 50/60Hz
182VAC ~ 264VAC, 50/60Hz
*Fuse Rating: 250V, 50T 3.15A
*Power Consumption: 130Watt ±20Watt
*Surge Current : 27A Peak (at 100VAC)
2. Signal Input
*Video: RGB Analog,
VGA Positive Signal (0.7V p-p / 75ohm)
CGA/EGA 2.5∼4Vp-p
*Sync: TTL Level, Positive or Negative Pulse
Separated1~5Vp-p
Composite1~5Vp-p
*Horizontal Scan: 15KHz ~ 32KHz
*Vertical Scan: 47Hz ~ 120Hz
*Resolution-Mode
Hf Vf Resolution
CGA 15.7KHz 60Hz 244H
EGA 24.8KHz 60Hz 381H
VGA 31.4KHz 60Hz 480H
3. Picture Tube
The Cathode Ray Tube shall be a LG Normal
& Dyna-Flat or equivalent
Size Dot Pitch Phosphor P/N
29 FST 0.82~1.1(H)mm P22 A68QBC230X
4. Pincushion
- 5% Maximum (All Brightness)
5. MTBF
- 20,000 Hours Minimum
6. Leakage Current
To chassis ground, at 220VAC, 50Hz (Line/Neutral in
common)
- 0.195mA Maximum
7. High Pot
Line/Neutral in common to secondary/chassis,
1500VAC 60Hz for 1 second
- 2.0mA Maximum, No Breakdown
8. Implosion Protection
- Provided by band and mounting lugs
9. Magnetic Shielding
- Internal
10. X-Radiation
- 0.50mR/hr Maximum
11. Mis-convergence
- Center : 0.40mm Maximum
- Corners : 2.0mm Maximum
12. Non-Linearity
Using a vertical and horizontal symmetrical cross
hatch pattern to equation for non-linearity will be
Non-linearity (%) = ((largest grid minus the smallest
grid) Divided by (largest grid plus
the smallest grid)) times 100.
- 10% maximum
13. Temperature
- Operating: 0° ~ 40°C
- Storage: -10°C ~ 60°C
- Humidity: 10% ~ 80%(Non-condensing)
14. Degaussing
Automatic at power-up and software via control
Switch “SEL”
15. Regulation (Static)
The horizontal and vertical size will change less than
4mm for a 25% white level abrupt luminance change.
16. Display Stability for Temperature
The temperature is cycled from 25°C to 0°C, and
from 25°C to 50°C the video size and centering drift
will not exceed 5mm horizontally or 4mm vertically.
(Measured after a 20 min. warm-up period at 25°C)
17. Monitor Test Specifications
Parameter Normal Tolerance
H/V 29.5KV +/- 500V
G2 500V +/- 10V
Brightness 0.50FL +/- 0.3FL
Contrast 60.0FL +/- 5FL
White Balance X: 0.281, Y: 0.311 +/- 0.015
*Test Mode: VGA 640 x 480(Fh: 31KHz, Fv: 60Hz)
*Signal: BSG-170 (BARO)
18. WARRANTY
Manufacturer warranty 2 years parts and labor.
(Except on C.R.T)
4
USER ADJUSTABLE CONTROLS
There are four switches on the control panel.
Adjustable controls allow the best display status for
individual preferences
Key Function
①MODE
*MODE - Call the Main-Menu OSD.
②SEL/DEGAUSS
*SEL – Select the function (sub-Menu OSD) on the
Main- Menu OSD.
*DEGAUSS – Do degaussing in state that the OSD
isn’t displayed.
③DOWN/UP
*When the Main-Menu is displayed, can search
each function using these keys.
*When the Sub-Menu is displayed (after select the
function), can change each
state of the screen using these
keys.
O.S.D Control Sub-P.C.B
O.S.D CONTROL METHOD
1) Control items.
Location Adjustment
Method
Function
SUB PCB OSD Control
Contrast
Brightness
Horizontal Position
Horizontal-Size
Vertical Position
Vertical-Size
Pincushion
Trapezoid
Color Gain
Call
MAIN PCB
VR control
VR101
VR401
VR901
FBT
Rotation
Sub-Bright
H.V Adjustment
Focus and Screen
OSD Controls
: User’s control.
A. BRIGHTNESS ADJUSTMENT
1) Press the “MODE” key then Main-Menu OSD come
out as below Figure.
2) Search “CONTRAST” sub-menu using “UP/DOWN”
key on the Main-Menu OSD.
3) Select the “CONTRAST” by pressing “SEL” key. Then
the “CONTRAST” Sub-Menu OSD comes out as
below figure.
4) Adjust Contrast as much as you want using
“UP/DOWN” key.
5) After finish the Contrast adjust, Press the “MODE”
key then the OSD goes back to Main-Menu.
6) If you want to adjust other function (sub-menu),
Search your wanting sub-menu like “BRIGHTNESS”
using “UP/DOWN” keys and then adjusts as same
way as item 3), 4) and 5).
7) Press the “MODE” key again to finish the
adjustment then the OSD disappeared.
B. BRIGHTNESS Adjusted as same way as above
C. H.POSITION Adjusted as same way as above
D. H-SIZE Adjusted as same way as above
E. V.POSITION Adjusted as same way as above
F. V-SIZE Adjusted as same way as above
H. PINCUSHION Adjusted as same way as above
I. TRAPEZOID Adjusted as same way as above
5
USER ADJUSTABLE CONTROLS
K. COLOR ADJUSTMENT
Press the “MODE” key then Main-Menu OSD come out
as below figure.
1) Search “CG” sub-menu using “UP/DOWN” key on
the Main-Menu OSD.
2) Select the “CG” by pressing “SEL” key, then the
color Sub-Menu OSD comes out as below figure.
3) Press “SEL” key to adjust “RED”,”GREEN” and
“BLUE”, The each “RED”,”GREEN” and “BLUE” is
selected by pressing the “SEL” key and selected
item changes OSD color from white to it’s own
color as character (ex: “RED” goes to red color)
4) Adjust “RED”,”GREEN” or “BLUE” using
“UP/DOWN” key.
5) Press “MODE” key to finish the color adjustment
then the OSD goes back to Main-Menu.
6) Press the “MODE” key again to finish the
adjustment then the OSD disappear.
L. RECALL
When press the “RECALL” key, all user’s adjustment
value are erased and covered by factory
adjustment value.
At first stage without any user’s adjustment, The
monitor set-upped by factory adjustment value.
Factory control (On Screen Display)
This monitor has two-adjustment mode.
One is for user’s own adjust and other is for factory
adjustment only.
But sometimes it needs to adjust at factory adjustment
mode for repair or development person.
Adjustment at the factory adjustment mode needs
more careful compare to user adjustment mode.
Because after finish the adjustment at factory mode, If
there are some mistake, can not recover to before
adjustment at the user mode, If there are mistake at the
user mode, can recover using “RECALL” function (refer
to “L. RECALL”).
A. Factory mode entering.
Press the “SEL” and “DOWN” key simultaneously until
OSD comes out as below.
The OSD of factory mode is same format with user
mode except color of bottom line.
B. Exit and save
1) After finish the adjustment; search “RECALL”
using “UP/DOWN” key.
2) Press “SEL” key until OSD disappear then the
adjusted value saved and exit from the factory
mode.
6
Factory control(On Screen Display)
C. Color Adjustment
All adjustment method is same with user’s control
mode except “COLOR”.
1) At the factory mode, Display VGA mode
2) Before adjust “CB”, “CONTRAST” and
“BRIGHTNESS” have to adjust 210.
(“CONTRAST” and “BRIGHTNESS” save each
mode(CGA, EGA and VGA)
3) Search “CB” using “UP/DOWN” key.
4) Select “CB” by pressing “SEL” key then color sub-
menu comes out as below figure.
5) Search gain or bias, which you want to adjust
using “UP/DOWN” key.
(“GAIN MODE” means high-beam area’s
adjustment and “BIAS MODE” means low-beam
area’s adjustment.)
6) Select an any item as wanting by pressing “SEL”
key.
7) The each “R”,”G” and “B” is selected by pressing
the “SEL” key and selected item changes OSD
color from white to it’s own color as character
8) Adjust color temperature using “UP/DOWN” and
“SEL” key.
(“UP/DOWN” key: change value, “SEL” key:
moves item position.)
9) Press “MODE” key to finish the adjustment then
main menu comes out as below figure.
10) If you want to adjust other function (sub-menu
“GAIN” or “BIAS”), Select “CB” by pressing “SEL”
key and then adjusts as same way as item 4), 5),
6) , 7) and 8).
11) If you want to adjust other mode (CGA, EGA),
Don’t adjust “CB”, Have to adjust “CONTRAST” and
“BRIGHTNESS”.
12) If you want to finish factory adjustment, Select
“RECALL” as item “B. Exit and save”
GAINMODE BIASMODE
(high-beam) (low-beam)
(fixed“SB”) (fixed“CB”)
OSD MODE
(Fixed)
HIGH VOLTAGE SHUT-DOWN CIRCUIT
The chassis of this monitor has been designed to emit
a minimum of soft X-radiation, in accordance with US
DHHS rules 21 CFR, subchapter. A high voltage shut-
down circuit, as shown below, guarantees horizontal
oscillation shut-down should the high voltage exceed
designed picture tube maximums.
DO NOT ATTEMPT TO MODIFY THIS CIRCUIT.
A fly back pulse is generated at pin (3) of the fly back
transformer.
After the pulse converted to DC through rectifying
circuit D415 & C452, it is input to IC403 pin (16)
through the divider network register R426 & R425.
Normally cathode voltage of ZD401 is below 12V, it is
not operated but in case of excess voltage it has to
be shut-down.
IC403 R424 C414 ZD401 R425 R426 C452 D415 FBT
Pin16 Pin3
GAIN MODE
SB 105
R 127
G 127
B127
BIAS MODE
CB 032
R 127
G 127
B127
OSD MODE
OC 105
7
BLOCK DIAGRAM
D.Y
G1 & Bright
Hor. BLK
ABL
H V
+B Control
D. Focus
Ver. BLK
H-Size
Pincushion
Hor. Out
FJL6920
S-Corection
H/V Pro.
KB2147
Ver. Out
TDA8172
FBT
SMPS
KA3842
2SK2676
170V
32V
15V
15V
6.3V
5V
Doubler
STR83145
AC
Input
Video
Output
Video
Pre AMP
KA2500
OSD
KS2508
BIAS
Video In
G1 G2 G4
Deflection
+B Control
+B
MCU
KS88P6116
EEPROM
24C04
Sync In
Control
H V. Out
2SC4770
High Voltage
G4, G2
+B
Hor. BLK
ABL
8
TROUBLE SHOOTING CHART
NO POWER NO VIDEO
CHECK &
REPLACEMENT
SECONDARY VOLTAGE OF T801
CHECK C842
AC LEVEL
NO POWER
YES
CHECK&
REPLACEMENT
F801,
POWER CORD
NO
CHECK C807
DC LEVEL
YES
CHECK Q802-D
WAVEFORM
YES
NO
CHECK&
REPLACEMENT
BD801, IC801
NO
CHECK&
REPLACEMENT
IC802
CHECK
SIGNAL CABLE
CHECK&
REPLACEMENT
SIGNAL CABLE
NO
YES
NO VIDEO
CHECK IC201
#21,24,26 PULSE
CHECK IC201
#23 DC LEVEL &
#18,19 PULSE
NO
NO
CHECK&
REPLACEMENT
IC101, Q103
YES
CHECK C206,
C210,C217 PULSE
CHECK&
REPLACEMENT
Q201~Q214
NO
CHECK&
REPLACEMENT
CRT SOCKET AND G1 CIRCUIT
YES
CHECK&
REPLACEMENT
IC201
YES
9
TROUBLE SHOOTING CHART
NO RASTER
CONTRAST
BRIGHTNESS
BRIGHTNESS
CHECK
G1 VOLTAGE
CHECK &
REPLACEMENT
Q411, D414
NO
NO
CHECK &
REPLACEMENT
R126, IC101
CHECK C115
VOLTAGE
YES
CHECK &
REPLACEMENT
SG201~204 VOLTAGE
CONTRAST
CHECK IC201
#12 VOLTAGE
CHECK &
REPLACEMENT
IC201, R903, ZD901
NO
NO
CHECK &
REPLACEMENT
IC101
CHECK IC201
#18 WAVEFORM
YES
CHECK &
REPLACEMENT
IC101
YES
NO RASTER
YES
CHECK &
REPLACEMENT
Q425, Q407
CHECK
H/V & G2
CHECK Q425
WAVEFORM
CHECK
G1 & DC 170V
CHECK BD404
DC 170V
CHECK &
REPLACEMENT
BD4
0
4
,
R
85
4
CHECK &
REPLACEMENT
G1 CIRCUIT
NO
YES
NO
NO
NO
CHECK &
REPLACEMENT
FBT, CRT
YES
YES
10
SERVICE NOTICS
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