Toshiba 2877DF Schematic
TOSHIBA 2877 DB
General Information
Also Covers
3377 DB
C7SS Chassis
Recommended Safety Parts
Item Part No. Description
C801 24082927 PF, 0.22uF, ±20%, AC275V
C813 24092557 CD, 2200pF, ±20%, AC125V
C814 24092557 CD, 2200pF, ±20%, AC125V
R899 24005007 MetaI-Glazed Resistor, 8.2M ohm, 1W
L901 23200276 Coil, Degaussing, TSB-2330BR (2877DB)
L901 23200215 Coil, Degaussing, TSB-2340AR (3377DB)
T461 23236447 Transformer, Flyback, TFB4115AR
T803 23217301 Transformer, Converter, TPW3336AR
Q826 A8643108 Photo Coupler, TLP621(GR-LF
F470 23144502 Fuse, 1.0A
F801 23144507 Fuse, 3.15A
F802 23144506 Fuse, 2.5A
S801 23344395 Switch, Power
V9O1A 23902891 Socket, CRT, 10P
Z889 23144543 Protector, PRF50005491, 125V, 5A
Z890 23144543 Protector, PRF50005491, 125V, 5A
Z891 23144543 Protector, PRF50005491, 125V, 5A
Z895 23144450 Protector, PRF2000, 125V, 2A
V901 23312715 Picture Tube, A66EAK552X21 (2877DB)
V901 23312653 Picture Tube, A80EFF002X11 (3377DB)
X-Ray Note
1. Excessive high voltage can produce potentially hazardous X-RAY RADIATION. To avoid
such hazards, the high voltage must not be
above the specified limit. The nominal value
of the high voltage of this receiver is 31 .5 kV
at zero beam current (minimum brightness)
under a 240V AC power source. The high
voltage must not, under any circumstances,
exceed (A) kV.
2877DB 3377DB
(A) 32kV 33kV
Each time a receiver requires servicing, the
high voltage should be checked following the
HIGH VOLTAGE CHECK procedure in this
manual. It is recommended that the reading of
the high voltage be recorded as a part of the
service record. It is important to use an
accurate and reliable high voltage meter.
2. The only source of X-RAY RADIATION in this
TV receiver is the picture tube. For continued
X-RAY RADIATION protection, the replacement tube must be exactly the same type tube
as specified in the parts list.
3. Some parts in this receiver have special
safety-related characteristics for X-RAY
RADIATION protection. For continued safety,
parts replacement should be undertaken only
after referring to the PRODUCT SAFETY
NOTICE below.
The following adjustments should be made
when a complete realignment is required or a
new picture tube is installed.
Perform the adjustments in order as follows:
1. Color Purity
2. Convergence
3. White Balance
Note: The PURITY/CONVERGENCE MAGNET
assembly and rubber wedges need mechanical
positioning.
Refer to figure 2.
COLOR PURITY ADJUSTMENT
NOTE : Before attempting any purity adjust-
ments, the receiver should be operated for at
least fifteen minutes.
1. Demagnetize the picture tube and cabinet
using a degaussing coil.
2. Set the brightness and contrast to maximum.
3. Use a green raster from among the built-in
test signals.
4. Loosen the clamp screw holding the yoke and
slide the yoke backward or forward to provide
vertical green belt (zone) in the picture
screen.
5. Remove the Rubber Wedges.
6. Rotate and spread the tabs of the purity
magnet (See figure 3.) around the neck of the
picture tube until the green belt is in the
center of the screen. At the same time, enter
the raster vertically.
7. Slowly move the yoke forward or backward
until a uniform green screen is obtained.
Tighten the clamp screw of the yoke temporarily.
8. Check the purity of the red and blue raster.
Figure 2
CONVERGENCE ADJUSTMENTS
NOTE: Before attempting any convergence
adjustments, the receiver should be operated for
at least fifteen minutes.
CENTER CONVERGENCE ADJUSTMENT
1. Use the cross-dot pattern from among the
built-in test signals.
2. Set the brightness and contrast for well
defined pattern.
3. Adjust two tabs of the 4-Pole Magnets to
change the angle between them (See figure
3.) and superimpose red and blue vertical
lines in the center area of the picture screen.
4. Turn the both tabs at the same time keeping
the angle constant to superimpose red and
blue horizontal lines at the center of the
screen.
5. Adjust two tabs of 6-Pole Magnets to
superimpose red/blue line and green one.
Adjusting the angle affects the vertical lines
and rotating both magnets affects the horizontal lines.
6. Repeat adjustments 3, 4, 5 keeping in mind
red, green and blue movement, because 4Pole Magnets and 6-Pole. Magnets have
mutual interaction and make dot movement
complex.
CIRCUMFERENCE CONVERGENCE ADJUSTMENT
1. Loosen the clamping screw of deflection yoke
slightly to allow the yoke to tilt.
2. Temporarily put a wedge as shown in figure 2.
(Do not remove cover paper on adhesive part
of the wedge.)
3. Tilt front of the deflection yoke up or down to
obtain better convergence in circumference.
(See figure 4.) Push the mounted wedge into
the space between picture tube and the yoke
to fix the yoke temporarily.
4. Put other wedge into bottom space and
remove the cover paper to stick.
5. Tilt front of the yoke right or left to obtain
better convergence in circumference. (See
figure 4.)
6. Keep the yoke position and put another
wedge in either upper space. Remove cover
paper and stick the wedge on picture tube to
fix the yoke.
7. Detach the temporarily mounted wedge and
put it in another upper space. Stick it on
picture tube to fix the yoke.
8. After fixing three wedges, recheck overall
convergence. Tighten the screw firmly to fix
the yoke and check the yoke is firm.
9. Stick three adhesive tapes on wedges as
shown in figure 2.
Figure 3
Figure 4.
1. ENTERING SERVICE MODE
1) Press button once on Remote Control.
2) Press button again to keep pressing.
3) While pressing the button, press MENU
button on TV set.
2. DISPLAYING THE ADJUSTMENT MENU
1) Press MENU button on TV.
3. KEY FUNCTION IN THE SERVICE MODE
The following key entry during display of
adjustment menu provides special functions. A
single horizontal line ON/OFF:
-/-- button (on Remote)
Test signal selection: button (on Remote)
Selection of the adjustment items: Channel UP/
DOWN (on TV & Remote)
Change of the data value:
Volume. +/- (on TV & Remote)
Adjustment menu mode ON/OFF: MENU button
(on TV)
Initialisation of the memory (QA02) :
CALL + Channel button on TV (UP)
Reset the count of operating protect circuit to
“00”: CALL + Channel button on TV (DOWN)
“RCUT” selection: 1 button
“GCUT” selection: 2 button
“BCUT” selection: 3 button
“CNTX” (or “SCNT”) selection: 4 button
“COLC” selection: 5 button
Color thickness
“TNTC” selection: 6 button correction
Test audio signal ON/OFF (1 kHz):
8 button note: Displayed differently as shown
below, depending on the setting of the receiving
color system.
COLP (PAL)
COLC (NTSC)
COLS (SECAM)
Self diagnostic display ON/OFF: 9 button
4. SELECTING THE ADJUSTING ITEMS
Every pressing of CHANNEL UP button
changes the adjustment items in the following
order. (DOWN button for reverse order.)
(See Table Opposite).
This item may require adjustments by models
after initialization, when QA02 is replaced.
5. ADJUSTING THE DATA
Pressing of VOLUME +/- button will change the
value of data in the range from 00 to FF. The
variable range depends on the adjusting item.
6. EXIT FROM SERVICE MODE
Press POWER button to turn off the TV once.
INITIALIZATION OF MEMORY DATA OF QA02
After replacing QA02, the following initialization
is required.
1) Enter the service mode, then select any
register item.
2) Press and hold the CALL button on the
Remote, then press the CHANNEL UP button
on the TV. The initialization of QA02 has been
completed.
3) Check the picture carefully. If necessary,
adjust any adjustment item above. Perform
“AUTO Search Memory”.
CAUTION: Never attempt to initialize the data
unless QA02 has been replaced.
TOSHIBA 2877 DB
Adjustments Cont’d
TEST SIGNAL SELECTION
Every pressing of button in the service mode
changes the test patterns on screen as described in SERVICE MODE.
Signal off NTSC signals (14 patterns)
PAL signals (14 patterns)
About inside signal: The inside signal is output
at video input terminal from QA01, and is not
output with the pin inserted into terminal. (Single
color signal can be output.)
SELF DIAGNOSTIC FUNCTION
1) Press “9” button on Remote Control during
display of adjustment menu in the service
mode. The diagnosis will begin to check if
interface among IC’s are executed properly.
2) During diagnosis, the following displays are
shown.
Model C7SS Series (Reference factory adjustment)
(1) Part number of microcomputer (QA01)
(2) Operation number of protecting circuit “00”,
is normal.When indication is other than “00”,
overcurrent apts to flow, and circuit parts may
possibly be damaged.
(3) BUS LINE CHECK ----“OK” is normal.
“SDA1-GND” means that SDA line is shorted to
ground.
“SCL1-GND” means that SCL line is shorted to
ground.
“SCL1-SDA1” means that SDA line is shorted to
SCL line.
(4) BUS CONT ----“OK” is normal.
When indication shows “Q OOO NG”, the device
with the number may possibly be damaged.
(5) BLOCK
UV : TV reception mode
V1: VIDEO 1 input mode ( 1)
V2: VIDEO 2 input mode ( 2)
Indicated color of mode now selected : Green
and Red Indicated color of other modes : White
Green: Normal
Red: The microcomputer operates to provide
judgement of no video signal. The red color is
still indicated though the signal is input, failure
may exist in input signal line including QV01.
QV01: In case of indication green ---Normal
In case of indication red with input signal ---Failure may exist in output line including QV01.
Model C7SS Series
Model C7SS Series (Only for the sets with SECAM function)
TOSHIBA 2877 DB
Back PCB Diagram
(2877DB)
TOSHIBA 2877 DB
Back PCB Diagram
(3377DB)
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