SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis IC Pin Voltage & Waveforms IC801 Pin Voltage & Waveform HC802 Pin Voltage & Waveform Pin No Stand-by Power On Pin No Stand-by Power On See printout See printout See printout See printout 11.1 V 12.5 V...
Page 8
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis IC Pin Voltage & Waveforms HC853 Pin Voltage & Waveform Pin No Stand-by Power On IC852 Pin Voltage & Waveform 12.9 V 13.7 V Pin No Stand-by Power On 0.6 V 11.8 V 37 V 129 V 3.8 V...
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis Power Supply Description Start up Circuit When AC cord is plugged in, the initial current starts flowing through the path as shown, and charges C852. When Vin reaches about 8V, the control circuit is activated, and the oscillation begins.
Page 10
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis Power Supply Description On-Time Control Circuit Description The oscillator generates driving pulses to turn PTR on/off by charging and discharging C1 and C2. Refer to the waveform shown below, left. When the PTR is on, C2 is charged to the constant voltage.
Page 11
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis Power Supply Description Off-Time Control Circuit Description The INH voltage is used as the input signal to the COMP1 and COMP2 within the control IC. Fig. 1 When INH voltage reaches Vth1, the OSC output is kept low, so PTR maintains off mode.
Page 12
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis Power Supply Description PTR Drive Circuit Description The control IC uses a proportional drive system to reduce the PTR ON loss, saturation loss, and storage time loss. When Proprot. drive circuit generates a positive pulse out of Pin 5, the base current to Pin 3 (base of PTR) develops, and increases linearly because of R813 and C851 combination.
Page 13
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis Power Supply Description OCP (Over Current Protection) Circuit Description) The overcurrent protection is performed by the pulse-by-pulse system, which directly detects the collector current of the PTR. The detect reference voltage to the comparator is set to -1 V...
Page 14
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis Power Supply Description Over Voltage Protection Circuit Description Latch Circuit Description The overvoltage protection circuit activates the latch circuit The latch circuit stops oscillation of the control IC when OVP when the Vin voltage exceeds about 11V.
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis Tuner Description TU01 TECC1080PA25A Tuner Band change-over system: PLL control system Tuning system: Electronic tuning system with PLL Voltage & Current at each terminal Terminal Supply Voltage Operation Guaranteed Voltage Current 12 +/– 0.1 V 12 +/–...
Page 39
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis POINT A POINT B POINT C POINT D...
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis IC Pin Description TDA8377 (IC201) Pin Description Pin No Pin Name Description SOUND IF INPUT 4.5 Mhz SIF signal input (1m Vrms max.) EXT AUDIO INPUT External Audio input VCO REF FILTER IF VCO tuning filter (2 X IF carrier freq.)
Page 43
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis IC Pin Description TDA8377 (IC201) Pin Description (continued) Pin No Pin Name Description X-TAL (3.58) 3.58 Mhz oscillation for chroma processing X-TAL (3.58/4.43) LOOP FILTER BURST Loop output response stabilization PHASE DET Power supply...
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis IC Pin Voltage & Waveforms TDA8377 (IC201) Pin Voltage & Waveforms Pin No Pin Name Voltage & Waveforms SOUND IF INPUT See print out EXT AUDIO INPUT 3, 4 VCO REF FILTER See print out...
Page 45
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis IC Pin Voltage & Waveforms TDA8377 (IC201) Pin Voltage & Waveforms (continued) Pin No Pin Name Voltage & Waveforms CVBS OUTPUT See print out BLACK PEAK HOLD 3.9 V H-OUT See print out SANDCASTLE OUTPUT FLYBACK See print out...
Page 46
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis IC201 PIN 3,4 IC201 PIN 5 IC201 PIN 6 IC201 PIN 7...
Page 47
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis IC201 PIN 8 IC201 PIN 10 IC201 PIN 11 IC201 PIN 13...
Page 48
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis IC201 PIN 18 IC201 PIN 20 IC201 PIN 26 IC201 PIN 27...
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis Horizontal Deflection Circuit Description 20/25 Horizontal Deflection Circuit Deflection current waveform...
Page 53
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis Horizontal Deflection Circuit Description 27 Inch Horizontal Deflection Circuit * QE01 C-E Resistance is controlled by DC current & Parabola voltage in vertical deflection time from EastWest Amp output in IC301...
Page 54
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis ACQUISITION MODE: PEAK DETECT ACQUISITION MODE: PEAK DETECT POINT A POINT B ACQUISITION MODE: PEAK DETECT ACQUISITION MODE: PEAK DETECT POINT C POINT E...
Page 55
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis ACQUISITION MODE: PEAK DETECT ACQUISITION MODE: PEAK DETECT POINT D POINT F ACQUISITION MODE: PEAK DETECT POINT G...
The set must be in Factory ('Service") Mode. Selection 3-1 Preadjustment sequence: STAND-BY –– MUTE––1––8––2––POWER Since there are no VRs in the KCT52A chassis,all adjustments after parts replacement must be done VIA the Service Mode. The "FACTORY MODE" message will be displayed.
Page 81
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis 3-2-1 Adjustment Selection sequence: STANDBY –– MUTE –– 1–– 8 ––2 –– POWER ON Example: Sub-bright Adjustment (see to the right)
Page 82
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis Main Adjustment Parameter 3.2.2 Test pattern (Aging Mode) Function RANGE DATA This mode can be used during servicing, or for confirm- Auto Gain Control 0~63 ing that the convergence and purity adjustments are cor-...
Page 83
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis 3-2-3 Set Option Byte Values Expressed in Hexadecimal Numbers In the Service Mode, various options can be selected VIA the Option Bytes; Example: BYTE 0 : 00 BYTE 1 : 00 FOR PIP MODEL...
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis 3.2.4 Factory Reset When "Factory Reset" is selected, the User-Control data reverts to the initial values. : The User-Control data is available at MENU (picture, sound and the other functions etc.) Note:When "Factory Reset" is selected,the Factory Mode Data does not change.
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis 3.3 Other Adjustments 3.3.1 General Usually, a color TV needs only slight touch-up adjustment upon installation Check the basic characteristics such as height, horizontal and vertical sync and focus. Observe the picture for good black and white details. There should be no objectionable color shading. If color shading is present, perform the purity and convergence adjustments described below.
Page 86
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis 3-3-2 Automatic Degaussing 3-3-3 High Voltage Check A degaussing coil is mounted around the picture tube, so CAUTION: There is no high voltage adjustment on this chas- external degaussing after moving the TV should be unneces- sis.
Page 87
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis 3.3.4 FOCUS Adjustment 3-3-6 F/S (Fail Safe) Circuit Check Input a black and white signal. The failsafe circuit check is the final step after servic- ing. Adjust the tuning control for the clearest picture.
Page 88
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis 3.3.7 Color Purity Adjustment Warm up the receiver. Operate it for 20 minutes, with the Brightness control set to maximum. Fully degauss the receiver. Use an external degaussing coil. Roughly adjust convergence by rotating the convergence magnet.
Page 89
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis Fig 3.2 Purity and Convergence Magnets...
Page 90
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis 3-3-8 Center Convergence Adjustment Note: Before attempting any convergence adjustment, make sure that the receiver has been powered ON for at least twenty minutes. Input a crosshatch pattern from a color bar generator. Adjust the Brightness and Contrast controls for a well defined pattern.
Page 91
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis 3-3-9 AGC Adjustment Input a COLOR-BAR pattern. (CH2) Set the RF input signal to 70DBuV. Use Generator for PM5518 & PM5418. Set AGC (in the Factory Mode) so that the DC level of IC TDA8377 Pin 33 is 3.2 (=0.05)V.
Page 92
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis 3-3-11 White Balance Adjustment 3-3-11 (D) SUB-BRIGHTNESS ADJUSTMENT Input a TOSHIBA pattern. Set SBT so that the brightness level in low-light is 3-3-11 (A) SCREEN ADJUSTMENTS 1.0F/L Input a TOSHIBA pattern. Check R506 "G" pin on the CRT PCB with an oscillos- cope.
Page 93
SAMSUNG GROUP SAMSUNG GROUP KCT52A Chassis 3-3-11 (F) SUB-TINT ADJUSTMENT Set "STT" in the Service Mode to step 2. 3-3-11 (G)VERTICAL SIZE ADJUSTMENT Input a lion head Pattern. Set "VS" to 32 in the Factory Mode. Set, "VA" so that the top margin is 4.0. Adjust "VSL" so that the bottom mm-gin is 4.0. If the top and bottom margins are different, adjust "VA"...