Service Manuals, User Guides, Schematic Diagrams or docs for : TOSHIBA TV toshiba_2857db
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TOSHIBA 2857 DB 1
General Information Service Mode General Picture
Chassis: C5SS Instructions
1. ENTERING TO SERVICE MODE
Matrix 1) Press button once on Remote Control.
Using method
Picture position (horizontal, vertical and slant) in
Item See Model Book CRT adjustment.
Adjustments (Not Service mode) .................................................................. 2152 DB 5 Making approx. 1 Vp-p signal in QA01.
Signals
Black cross-hatch
X-RAY RADIATION PRECAUTION 2. It is essential that to maintain the safety of the
White cross-hatch
customer all cable forms be replaced exactly
1. The E.H.T. must be checked every time the as supplied from factory. 2) Press button again to keep pressing. Picture
receiver is serviced to ensure that the C.R.T. 3. A small part of the chassis used in this
does not emit X-ray radiation as result of receiver is, when operating, at approximately
excessive E.H.T. voltage. The nominal E.H.T. half mains potential at all times. It is therefore
for this receiver is 31.5 kV at zero beam essential in the interest of safety that when
current (minimum brightness) operating at serving or connecting any test equipment the
240V a.c. The maximum E.H.T. voltage receiver should be supplied via a suitable
Using method
permissible in any operating circumstances isolating transformer of adequate rating.
Convergence and vertical amplitude adjustment
must not exceed 32.0 kV. When checking the 4. Replace blown fuses within the receiver with
Making approx. 1 Vp-p signal in QA01.
E.H.T., use the `High Voltage Check' proce- the fuse specified in the parts list. 3) Keep pressing the button, press MENU
dure, using an accurate E.H.T. voltmeter. 5. When replacing wires or components to button on TV set. Signals
2. The only source of X-RAY radiation in this terminals or tags, wind the leads around the
Black cross-dot
receiver is the C.R.T. To prevent X-ray terminal before soldering. When replacing
White cross-dot
radiation, the replacement C.R.T. must be safety components identified by the interna- RCUT S
identical to the original fitted as specified in tional hazard symbols on the circuit diagram 32H Picture
the Parts List. and parts list, it must be a Toshiba approved
3. Some components used in this receiver have type and must be mounted as the original.
safety related characteristics preventing the 6. Keep wires away from high temperature
C.R.T. from emitting X-ray radiation. For components.
continued safety, replacement component (Service mode dIsplay)
should only be made after referring the PRODUCT SAFETY NOTICE
Using method
Product Safety Notice below. 2. SELECTING THE ADJUSTING ITEMS Convergence adjustment
Many electrical and mechanical components in Every pressing of CHANNEL v button changes Making approx. 1Vp-p signal in QA01.
SAFETY PRECAUTION this chassis have special safety-related the adjustment items in the following order.
characteristics. These characteristics are often (w button for reverse order.) Signals
1. This receiver has a nominal working E.H.T. passed unnoticed by a visual inspection and the
H signal (Left, right, white)
voltage of 28.5 kV. Extreme caution should be X-ray radiation protection afforded by them 3. ADJUSTING THE DATA H signal (Left, right, black)
exercised when working on the receiver with cannot necessarily be obtained by using
the back removed. Do not attempt to service replacements rated at higher voltages or Pressing of VOLUME v or w button will change Picture
this receiver if you are not conversant with the wattage, etc. Components which have these the value of data in the range from 00 to FF. The
precautions and procedures for working on special safety characteristics in this manual and variable range depends on the adjusting item.
high voltage equipment. When handling or its supplements are identified by the interna-
working on the C.R.T., always discharge the tional hazard symbols on the schematic diagram 4. NORMAL OPERATION ON THE SERVICE
anode to the receiver chassis before remov- and parts list. Before replacing any of these MODE
ing the anode cap The C.R.T., if broken, will components read the parts list in this manual
Using method
violently expel glass fragments. Use shatter carefully. Substitute replacement components Press MENU button on TV. For checking (of purity drift) of white uniformity
proof goggles and take extreme care while which do not have the same safety characteris-
of CRT H signal (Left, right, white).
handling. Do not hold the C.R.T. by the neck tics as specified in the parts list may create X- Adjustment mode Service mode Check in light area.
as this is a very dangerous practice. ray radiation.
TEST SIGNAL SELECTION Stopping G and B output of Q501 H signal (Left, right, black).
RCUT Address S Green single colour. Check in dark area.
32H Data Press
Every pressing of button changes the test Stopping R and B output of Q501 The adjustment will be the best, if the time when
patterns on screen as described below in Blue single colour. unevenness of color in light area occurs, is a
Press
Recommended Safety Parts SERVICE MODE. Stopping R and G output of Q501 little longer than that in dark area.
Making approx. 1Vp-p signal in QA01.
Black single colour.
Item Part No. Description Signal off NTSC signals (14 patterns) Making black signal of approx. 1Vp-p in QA01
5. EXIT FROM SERVICE MODE White single colour.
A401 23426393 Back Cover Making white signal of approx. 1Vp-p in QA01
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