1
TOSHIBA 2857 DB
General Information
Chassis: C5SS
A401
23426393
Back Cover
C440
24082482
PF, 7000pF,
±
3%, 1500V
C441
24082669
PF, 0.33
µ
F, 250V
C442
24082672
PF, 0.43
µ
F, 250V
C444
24082519
PF, 6200pF,
±
3%, 1800V
C463
24212222
CD, 2200pF,
±
10%
C801
24082374
PE, 0.22
µ
F, AC250V
C805
24092281
CD, 4700pF,
±
20%, AC250V
C806
24092281
CD, 4700pF,
±
20%, AC250V
R801
24009954
Metal-Glazed Resistor, 2.2M ohm, 1/2W
R808
24019340
PTC Thermistor, 18 ohm, 290V
R810
24007489
Cement, 3 ohm, 20W
R811
24568271
Cement, 270 ohm, 7W
R824
24569689
Cement, 6.8 ohm, 10W
R841
24531120
FR, 12 ohm, 1/2W
R899
24005007
Metal-Glazed Resistor, 8.2M ohm, 1W
L462
-------------
DY, Supplied with V901
L901
23200276
Coil, Degaussing, TSB-2330BR
T401
23224336
Transformer, Horiz. Drive, TLN1083
T461
23236447
Transformer, Flyback, TFB4115AR
T801
23211891
Line Filter, TRF3164
T803
23217301
Transformer, Converter, TPW3336AR
Q404
A6872801
Transistor, 2SD2253(FA)
Q801
23905084
IC, STR-S6709
Q826
A8643106
Photo Coupler, TLP621(GR)
D801
23316795
Diode, D6SB60L,F05
F470
23144873
Fuse, 1.0A
F801
23144898
Fuse, 3.15A
P801
23372012
Power Cord
V901A
23902891
Socket, CRT, 10P
V901
23312645
Picture Tube, A66EAK252X21
Recommended Safety Parts
Item
Part No.
Description
X-RAY RADIATION PRECAUTION
1. The E.H.T. must be checked every time the
receiver is serviced to ensure that the C.R.T.
does not emit X-ray radiation as result of
excessive E.H.T. voltage. The nominal E.H.T.
for this receiver is 31.5 kV at zero beam
current (minimum brightness) operating at
240V a.c. The maximum E.H.T. voltage
permissible in any operating circumstances
must not exceed 32.0 kV. When checking the
E.H.T., use the ‘High Voltage Check’ proce-
dure, using an accurate E.H.T. voltmeter.
2. The only source of X-RAY radiation in this
receiver is the C.R.T. To prevent X-ray
radiation, the replacement C.R.T. must be
identical to the original fitted as specified in
the Parts List.
3. Some components used in this receiver have
safety related characteristics preventing the
C.R.T. from emitting X-ray radiation. For
continued safety, replacement component
should only be made after referring the
Product Safety Notice below.
SAFETY PRECAUTION
1. This receiver has a nominal working E.H.T.
voltage of 28.5 kV. Extreme caution should be
exercised when working on the receiver with
the back removed. Do not attempt to service
this receiver if you are not conversant with the
precautions and procedures for working on
high voltage equipment. When handling or
working on the C.R.T., always discharge the
anode to the receiver chassis before remov-
ing the anode cap The C.R.T., if broken, will
violently expel glass fragments. Use shatter
proof goggles and take extreme care while
handling. Do not hold the C.R.T. by the neck
as this is a very dangerous practice.
TEST SIGNAL SELECTION
Every pressing of button changes the test
patterns on screen as described below 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.)
Signals
Red single colour
Green single colour
Blue single colour
Black single colour
White single colour
Picture
Using method
Purity and White uniformity of CRT
Red single colour.
Stopping G and B output of Q501
Green single colour.
Stopping R and B output of Q501
Blue single colour.
Stopping R and G output of Q501
Black single colour.
Making black signal of approx. 1Vp-p in QA01
White single colour.
Making white signal of approx. 1Vp-p in QA01
Signals
W/B adjustment
Picture
Using method
White balance adjustment
White .
White balance adjustment/check in light area
Black part.
White balance adjustment/check in dark area.
Making. approx. 1Vp-p signal in QA01.
Signals
Black cross-bar
White cross-bar
2. It is essential that to maintain the safety of the
customer all cable forms be replaced exactly
as supplied from factory.
3. A small part of the chassis used in this
receiver is, when operating, at approximately
half mains potential at all times. It is therefore
essential in the interest of safety that when
serving or connecting any test equipment the
receiver should be supplied via a suitable
isolating transformer of adequate rating.
4. Replace blown fuses within the receiver with
the fuse specified in the parts list.
5. When replacing wires or components to
terminals or tags, wind the leads around the
terminal before soldering. When replacing
safety components identified by the interna-
tional hazard symbols on the circuit diagram
and parts list, it must be a Toshiba approved
type and must be mounted as the original.
6. Keep wires away from high temperature
components.
PRODUCT SAFETY NOTICE
Many electrical and mechanical components in
this chassis have special safety-related
characteristics. These characteristics are often
passed unnoticed by a visual inspection and the
X-ray radiation protection afforded by them
cannot necessarily be obtained by using
replacements rated at higher voltages or
wattage, etc. Components which have these
special safety characteristics in this manual and
its supplements are identified by the interna-
tional hazard symbols on the schematic diagram
and parts list. Before replacing any of these
components read the parts list in this manual
carefully. Substitute replacement components
which do not have the same safety characteris-
tics as specified in the parts list may create X-
ray radiation.
1. ENTERING TO SERVICE MODE
1) Press
button once on Remote Control.
2) Press
button again to keep pressing.
3) Keep pressing the
button, press MENU
button on TV set.
RCUT
S
32H
(Service mode dIsplay)
2. SELECTING THE ADJUSTING ITEMS
Every pressing of CHANNEL
▲
button changes
the adjustment items in the following order.
(
▼
button for reverse order.)
3. ADJUSTING THE DATA
Pressing of VOLUME
▲
or
▼
button will change
the value of data in the range from 00 to FF. The
variable range depends on the adjusting item.
4. NORMAL OPERATION ON THE SERVICE
MODE
Press MENU button on TV.
Adjustment mode
Service mode
RCUT
Address
S
32H
Data
5. EXIT FROM SERVICE MODE
Press POWER button on the remote control to
turn off the TV once.
OTHER SERVICE FUNCTION
The following key entry during display of
adjustment menu provides special functions.
Press
Press
Service Mode General
Instructions
Picture
Using method
Picture position (horizontal, vertical and slant) in
CRT adjustment.
Making approx. 1 Vp-p signal in QA01.
Signals
Black cross-hatch
White cross-hatch
Picture
Using method
Convergence and vertical amplitude adjustment
Making approx. 1 Vp-p signal in QA01.
Signals
Black cross-dot
White cross-dot
Picture
Using method
Convergence adjustment
Making approx. 1Vp-p signal in QA01.
Signals
H signal (Left, right, white)
H signal (Left, right, black)
Picture
Using method
For checking (of purity drift) of white uniformity
of CRT H signal (Left, right, white).
Check in light area.
H signal (Left, right, black).
Check in dark area.
The adjustment will be the best, if the time when
unevenness of color in light area occurs, is a
little longer than that in dark area.
Making approx. 1Vp-p signal in QA01.
➜
➜
➜
➤
➤
➤
➤
➤
➤
Matrix
Item
See Model
Book
Summary of Contents for 2857 DB
Page 4: ...4 TOSHIBA 2857 DB AV PCB Diagram ...
Page 5: ...5 TOSHIBA 2857 DB Comb Delay PCB Diagram ...
Page 6: ...6 TOSHIBA 2857 DB Pro Logic Diagram ...
Page 7: ...7 TOSHIBA 2857 DB Signal Processing Diagram ...
Page 8: ...8 TOSHIBA 2857 DB Signal Processing Diagram Cont d ...
Page 9: ...9 TOSHIBA 2857 DB Power Deflection Diagram ...
Page 10: ...10 TOSHIBA 2857 DB Power Deflection Diagram Cont d Text PCB Diagram ...
