KORTEK KT-1903NA
Manual de Servicio

KORTEK Corporation KT-XX03NA
IC101 pin 1 has OSC function embedded in chip so that, at the first time when power switch is turned on, embedded OSC oscillates to drive circuits. After the initial operation, it inputs pulse separated flowing out from FBT in IC101 Pin 5 to match frequencies of monitor and power supply so that it minimizes noise from oscillation and from interference between frequencies of monitor and power supply. Also, when distance between trans and deflection yoke is near, it prevents noise from being generated on screen. The switching trans changes and supplies the generated pulse adequately for voltage of each part of monitor, and IC101 Pin 4 receives feedback for difference in voltages output to terminal receiving feedback for variations of voltage, and increases voltage when it is low, and lowers when it is low, so supplying the secondary voltage stably. T101 secondary side receives the output of the pulse provided to the primary side. T101 pin 9 rectifies the voltage at the D116, smoothes it at C116 and outputs 125 V and provides it to the video output terminal. R117 and C117 are the circuits to improve the FCC and smoke noises. "T101 Pin 9 is made up of +125V D116, C116, J175 and R116 circuit." "Pin 10 and Pin 14 are GNG on the secondary voltage. "Pin 11 supplies voltage to CRT heater in +6.3V line and its circuit is composed of D111, C123 and R123. Pin 12 supplies operating voltage of video pre amp, horizontal & vertical OSC IC in +12V line, and its circuit is composed of D112, C126 and R126. With regard to R111, IC102, Q101, R110, C115, R112, VR101 and R114, in order to supply voltage to the second side stably, the voltage provided to IC102 through R111 oscillates the light emission element and generates the potential and feeds back it to IC101 pin4. Then, it maintains and controls a stable voltage of the secondary side. Also, they can control B+ voltage using Q101 V/R101, so controlling desired voltage. Pin 13 is a circuit supplying B+ of vertical output amp and horizontal drive in +26V line and its circuit is composed of D110 and C119, BD104 and C122. Pin 15 supplies B+ voltage of FBT in 54V line and its circuit is composed of D109, C118, D114 and C121. Pin 16 is output for compensating for voltage according to frequency changes and its circuit is composed of D108, BD101, C124, D118, R118 and Q102. Because, with horizontal frequency, B+ of FBT varies with Q102 operation, this is a circuit for compensating for this. Other circuits of power supply constitute manual degaussing circuit with PH101.