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 CHASSIS

Issued: 17th September 2001

    

  PAL I SYSTEM COLOUR TELEVISION

   SEBD21HT15H00

In the interests of user safety (required by safety
regulations in some countries) the set should restored
to its original condition and only parts identical to
those specified should be used.

ELECTRICAL SPECIFICATION.........................3
IMPORTANT SERVICING NOTES ...................4
CONTROLS & TERMINALS..............................5
SERVICE ADJUSTMENTS................................6
CHASSIS LAYOUT...........................................12
LED FLASHING CODE....................................13

PRINTED WIRING BOARDS...........................13
ICs ADITIONAL INFORMATION......................18
SCHEMATIC DIAGRAM, WAVE FORMS........24
BLOCK DIAGRAM...........................................30
TROUBLESHOOTING TABLES......................32
PARTS  LISTING.............................................35

CONTENTS

Use this page to keep any special servicing information as Technical Report (Bulletin), Technical Information, etc.
If only part  number changes are required, just change part number directly the part number in the Parts Listing Section.
If you need more information, please refer to the Technical Report (Bulletin).

•

Power Input .......................220V-240 Volts AC 50Hz

•

Power Consumption

•

Audio Power Output Rating .....................4W (MPO)

Speaker................................16

Ω

 4W, 9 x 5 cm,

  

1pc

Normal Operation....................................43W

Stand-by Operation...................................3W

•

White Level

Set  the brightness control, with no signal connected, so that  the CRT cathode current is 600mA.  The maximum
correction applied to each cathode current to achieve a screen temperature of 8900 degrees K-3 MPCD should not
exceed 15% of its original value.

Convergence.........................Self Converging System

Focus....................................Bi-Potencial Electrostatic

Sweep Deflection...........................................Magnetic

•

Aerial Input Impedance

VHF/UHF..........................75 ohm Unbalanced

•

Tuning Ranges ............45.75MHz thru 855.25 MHz

         VHF.............IR A - J

                                        S1-S41 (HYPERBAND)
                    UHF.............I21 - I69 CH

•

Picture Intermediate Frecuency.....

.........38.9MHz

•

Sound  Carrier Trap

...............................32.9MHz

•

Adjacent  Sound Carrier Trap

.................40.9MHz

•

Adjacent  Picture  Carrier Trap

...............30.9MHz

The chassis in this receiver is partially hot. Use an isolation transformer between the line cord plug
and power receptacle, when servicing this chassis.
To prevent electric shock, do not remove cover. No user-serviceable parts inside. Refer servicing to
qualified service personnel.

Specifications are subject to change without prior notice.

•

MODEL 

X 

Y Screen 

temperature 

21HT-15H 

0.290 

±

 0.015 

0.284 

±

 0.015 

8900º K-20 MPCD 

Only qualified service personnel are allowed to carry out maintenance and repair of this receiver.

It is important that the static charge is removed from the high voltage system when carrying out work
on the receiver. This can be achieved by connecting a 10K resistor (with a suitably insulated lead) from
the CRT cavity connector to the CRT ground tag. This must be carried out with the AC supply discon-
nected from the receiver.
Note the following:

•

 The CRT in this receiver employs Integral Implosion Protection.

•

 If the CRT has to  be changed  it  MUST  be  replaced  with  the  correct  type for continued safe

working

•

 DO NOT lift the CRT by its neck.

•

 When handing the CRT, ensure that shatterproof goggles are worn.

•

 Ensure that the CRT is discharge before handling.

This receiver is designed to keep any x-ray emission to an absolute minimum. Some fault conditions
and servicing procedures may produce potentially hazardous x-ray radiation levels. This is a problem
when in close proximity to the receiver for long  periods of time. To reduce any risks associated with
this, please observe the following precautions:

1. When undertaking any servicing on this chassis, DO NOT increase the EHT  to more than 30.5 KV,
   (at a instantaneous beam current of 1300

µΑ).

2. Ensure that during normal operation the EHT does not exceed 25.0 KV

±

1.5KV (at a beam current of

   1100

µΑ). 

This level has been preset in the factory. Always check that this level has not been ex-

ceeded after carrying out any repair on the receiver.

3. DO NOT replace the CRT with any other type than that specified in the parts listing as this may
   cause excessive x-ray radiation.

In addition to the above checks, the following should also be carried out before  returning the receiver
to the customer.

1. Inspect all the leads to ensure that they are dressed correctly and that they are not obstructed or
    pinched by any other parts.
2. Ensure that all protective devices are in good condition. These will include nonmetallic control
   knobs, insulating fish papers, cabinets backs, compartment covers or shields, mechanical insulators,
    etc.