This part is a kind of semiconductor called C5803.

Function of this product has KSC5803.

Manufacturers : KEC

Image and pinout :

Some of the text within the PDF file :

KSC5803 KSC5803 High Voltage Color Display Horizontal Deflection Output (No Damper Diode) • • • • High Breakdown Voltage : BVCBO=1500V High Speed Switching : tF=0.1µs (Typ.) Wide S.O.A For C-Monitor(85KHz) TO-3PF 2.Collector 3.Emitter 1 1.Base NPN Triple Diffused Planar Silicon Transistor Absolute Maximum Ratings TC=25°C unless otherwise noted Symbol VCBO VCEO VEBO IC ICP PC TJ TSTG Parameter Collector-Base Voltage Collector-Emitter Voltage Emitter-Base Voltage Collector Current (DC) Collector Current (Pulse) Collector Dissipation (TC=25°C) Junction Temperature Storage Temperature Value 1500 800 6 12 24 70 150 - 55 ~ 150 Units V V V A A W °C °C Electrical Characteristics TC=25°C unless otherwise noted Symbol ICES ICBO IEBO hFE1 hFE2 VCE(sat) VBE(sat) [ ... ]

C5803 PDF Datasheet Download