Samsung SF-335T Repair Manual

Also see for SF-330 Series: Quick install guide Operating instructions User manual Service guide

Contents

CIRCUIT DESCRIPTION3.1.6.2 QUARTERHORSE FUNCTION<1> PEN / MOTOR SUPPLY VOLTAGE REGULATORIt receives the inputted power of +24V, and the power flows to the buck type regulator, which consists of the external N-chan-nel FET and SCHOTTKY diode, to make +19.2V. The power uses as the main power of the ink head, CR, and LF, SS MOTOR.<2> +5V REGULATORThe +24V (inputted power) is supplied, and it becomes +5V of the logic power by using the internal switching FET Buck typeregulator. It becomes +3.3V to support the main power of the CPU by using external +3.3V Regulator, and the +3.3V becomes+1.8V to support the internal power of the CPU by using +1.8 Regulator.<3> RESET CIRCUITThe Reset of the Quarter-horse starts to work when the +5V is going down under +4.75V. It has the 1.5~5 usec of SensitivityTiming Margin for preventing the minute shakiness of the power by ESD. Also, the Time Delay of the Reset can be controlledfrom 1ms to 1s by the Capacitor when power on.<4> MOTOR DRIVERSThe Quarter-horse drives one DC Motor and two stepping motors. The DC Motor drives +19.2V as the FULL H-BRIDGE, andthe direction information goes to the CPU via the Serial Interface port. Also, it is inputted the PWM Modulator from CPU. TheStepping Motor is driven by the UNIPOLAR, and the phase information is transmitted to the CPU via the Serial Interface port.1. DC MOTOR TRUTH TABLEDCA DCB PWM A high side A low side B high side B low side0 0 X off on off on0 1 0 on off on off0 1 1 off on on off1 0 0 on off on off1 0 1 on off off on1 1 X on off on off