ELEKTA CTR1498 Schematic

CONTENTS

X-RAY RADIATION PRECAUTION 2
SAFETY PRECAUTION 2
OPERATIONCONTROLS 3
GENERAL ADJUSTMENT INSTRUCTION 4-8
COLOR PURITY AND CONVERGENCE ADJUSTMENT 9-10
COMPONENT AND BOTTOM VIEW 11-13
WIRING DIAGRAM 14
SCHEMATIC DIAGRAM 15
BLOCK DIAGRAM 16
ELECTRICAL PARTS LIST 17-25
EXPLODED VIEW 25
MECHANICAL PARTS LIST 27-28

SPECIFICATIONS 28

CAUTION: BEFORE SERVICING THE CHASSIS, READ THE' SAFETY PRECAUTION ",'X-RAY RADIA­ TION PRECAUTION " AND ' PROOUCT SAFETY NOTICE " ON PAGE 2 OF THIS MANUAL.

NOTICE: THE POWER SUPPLY ClRCUIT OF THIS RECEIVER IS A " HOT " CHASSIS, THE REST ARE
" COLD " CHASSIS.

X-RAY RADIATION PRECAUTION

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 normal value of th high voltaga of this receiver is 25kV at zero beam current
( minimum brightness ) under 220V AC power source. The high voltage must not, under any ciraurtstancss, exceed 26kV.

2. Each time a receiver requires servicing, the high voltage should be checked following the HIGH VOLTAGE CHECK PROCEDURE
in this manual. It is recommended 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.

3. The primary source of X-RAY RADIATION in this TV receiver is the picture tube. For continued

X-RAY RADIATION protection, the replacement tuba must be exactly the same type tube as specfied in the parts list,

4. Some parts in this receiverhave special-safety-related charaderistics for X-RAY RADIATION protection. For continued

safety, parts replacement should be undertaken only after referrfng to the PRODUCT SAFETY NOTICE below.

5. The receiver is equipped with X-RAY RADIATION circuit. When the high voltage reach a set value, the circuit will set the

receiver to STAND BY mode to prevent the receiver from producing excessive amount of X-RAY RADIATION.

SAFETY PRECAUTION

WARNING:

Service should not be attempted by anyone unfamiliar with the necessary precaution on this receiver. The following are the
necessary precautions to the observed before servicing this chassis.

1. Since the power suppfy circuit of this receiver is directly connected to the AC power line, an isolation transformer should
be used during any dynamic service to avoid possible shock hazard.

2. Always discharged the picture tube anode to the CRT conductive coating before handling the picture tube. The picture tube
is highly evacuated and if broken, glass fragments will be violently expeIied. Use shatter proof goggles and keep picture
tube away from the unprotected body while handling.

3. When replacing a chassis in the cabinet. always be certain that all the protective devices ara put back in place, such as:
non-metallic control knobs, Insulating covers, shields, isolation resistor-capacitor network etc,

4. When replacing parts or cirduit boards, disconnect the power cord.

5. When replacing a high voltage ressistor ( oxide metal film resistor ) on the circuit board. keep ihe resistor l0mm (1 / 2in)
away from circuit board.

6. Connection wires must be kept away from components with high voltage or high temperature.

7. If any fuse in this TV receiver is blown, replace it with the FUSE specified in the chassis parts list.

8. The receiver is designed to operate with 220V ( 50Hz ) AC mains.

9. Replace any components according to the requirement after reading the parts list in this manual.

PRODUCT SAFETY NOTICE

Many electrical und mechanical parts in the chassis have special safety-related characteristics. These characteristics are otten passed
unnoticed by a visual inspecson and the X-RAY RADIATION protection afforded by them cannot necessarily be obtained by using
replacement components rated for higher wattage, etc. Repladement parts which have tese special safety characteristics are identified
in this manual and its supplements electrical components having such features are shaded on the schematic diagram and the parts Iist.
Before replacing any of these components, read the parts list in this rnanual carefully. The use of substitute replacement parts which do
not have the same safety characteristic as specified in the parts list may create shock, fire, X-RAY RADIATION other or hazards.

OPERATION CONTROLS

VOLUME CONTROL

(

UP /

DOWN )

INFRARED REMOTE

AUDIO IN

AC CORD

( UP / DOWN )

CHANNEL SELECTOR

SPEAKER

CONTROL DOOR

POWER SWITCH

LED

SENSOR

MANUAL TUNING AUTO PRESET STAND BY

PRESET ON/OFF SKIP

ANTENNA TERMINALS

GENERAL ADJUSTMENT INSTRUCTION

This receiver is transistorized and special care should be taken when servicing. Read the following matters that demand
special attention before attempting adjustment.

1. Adjustment requires and exact procedure and should be under taken only when necessary.

2. An isolation transformer should be used during any dynamic service to avoid possible shock hazard.

3. The test equipment specified or its equvalent is required to perform the alignment property. Use of equipment which does
not meet these requirements may result in improper alignment.

4. Correct matching of the equipment is essential. Failure to use proper matching will result in responses which can not
repressent the lure operation of receiver.

5. The AC power line voltage should be kept 215 to 225 volts 50Hz during alignment

6. Do not attempt to connect or disconnect any wire while the receiver is in operation. Make sure the power cord is
disconnected before replacing parts in the receiver.

7. Unless otherwise noted, do not perform arty adjustment until the receiver has been turned on for at least 10 minutes.

Note: For safety sake, the following adjustment should be conducted with the low voltage DC supply to avoid shock hazard.

TEST EQUIPMENTS

1. AM / FM signal generator ( 4.5MHz-6.5MHz )

2. Sweep / Marker signal operator ( 30MHz~60MHz )

3. Sync. oscilloscope

4. Oscilloscope ( volt sensitivity over 10mV and input impedance having 1MO, below 10PF )

5. Probe ( Low capacitance )

6. High impedance electronic voltmeter on VTTM ( Input impedance having 100kO / V at leasti )

7. DC power supply ( Source such as a battery or a well regulated and isolated DC bias supply )

8. Frequency counter.

PICTURE AND SOUND I. F. ADJUSTMENT

1. Picture I. F. Alignment

(a) Connect the signal output of sweep / marker generator to the Test Point of tuner through 1 kO resistor and 1 OOOPF capaci-

tor ( See Fig. 1 ).
(b) Connect the vertical input terminal of an sync oscilloscope in series with a 100kO resistor to TP4.
(c) Apply a + 12V DC across C120 on Main Board.
(d) Apply a + 8V DC dummy AGC bias to Pin 5 of IC101.
(e) Tune L105 and L109 to obtain a waveform as show in Fig. 2.

2. AFC OVERALL RESPONSE ALIGNMENT

(a) Act the step (a), (c) and (d) of Picture I. F. Alignment.
(b) Reconnect oscilloscope to TP5 through a 1 MO resistor.
(c) Adjust coil L110 that 38.9MHz, Marker is set at the center position as shown in Fig. 3.

3. SIF ALIGNMENT ( 5.5MHz )

(a) Set signal generator output to 5.5MHz with AF 1 kHz, 75kHz FM modulation output level 60dB. Apply the signal to TP6

through a 1kO resistor and a 1OOOPF capacitor. As show in Fig. 4.
(b) Connect the oscilloscope input in series with a 100kO resistor to TP7
(c) Apply a + 12V DC across C120.
(d) Fine adjust L108 to abtain a maximum amplitude signal output with minimum distortion.

Note: In case of the D / K system, sound carrier frequency should be at the point of 6.5MHz and video carrier frequency at the point of

38.0MHz.