background image

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

Adjustments (Not Service mode) .................................................................. 2152 DB

5

Содержание 2857 DB

Страница 1: ...lour 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 ...

Страница 2: ...ervice mode and get the inside W B adjusting signal with VIDEO button 3 Select RCUT GCUT and BCUT with CHAN NEL buttons to set individual values to 32 and to set GDRV and BDRV to 20 with VOLUME buttons 4 Press button on the remote control and rotate Screen VR to get one slight horizontal line on screen Note Every pressing of button provides Horizontal line picture and Normal picture alternately 5 ...

Страница 3: ...L 29H NICH 00H NICAM THRESHOLD LEVEL 2AH IDL 00H IGR THRESHOLD LEVEL 2BH IDH 00H IGR THRESHOLD LEVEL 20H EVOL 00H EXT PRE VOLUME 2DH EMX FCH NICAM ON LEVEL 2EH EMN 64H NICAM OFF LEVEL 2FH FMA 00H FM ATTENUATOR LEVEL 30H STS 00H STEREO SEPARATION F 31H HPOS 15H 50Hz H POSITION 32H VPOS 04H V POSITION 33H HIT 3EH HEIGHT 37H VLIN 11H V LINEARITY 38H VSC 0FH V S CORRECTION 39H VPS 0EH V SHIFT 3AH VCP ...

Страница 4: ...4 TOSHIBA 2857 DB AV PCB Diagram ...

Страница 5: ...5 TOSHIBA 2857 DB Comb Delay PCB Diagram ...

Страница 6: ...6 TOSHIBA 2857 DB Pro Logic Diagram ...

Страница 7: ...7 TOSHIBA 2857 DB Signal Processing Diagram ...

Страница 8: ...8 TOSHIBA 2857 DB Signal Processing Diagram Cont d ...

Страница 9: ...9 TOSHIBA 2857 DB Power Deflection Diagram ...

Страница 10: ...10 TOSHIBA 2857 DB Power Deflection Diagram Cont d Text PCB Diagram ...

Отзывы: