This post explains for the transistor.
The Part Number is J6812, FJAF6812.
The function of this semiconductor is 750V, 12A, NPN Transistor.
The package is TO-3PF Type
Manufacturer: Fairchild Semiconductor
Preview images :
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Description
The J6812 is NPN Triple Diffused Planar Silicon Transistor.
Features
1. High Collector-Base Breakdown Voltage : BVCBO = 1500V
2. High Switching Speed : tF(typ.) =0.1µs
3. For Color Monitor
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Absolute maximum ratings ( Ta=25°C )
1. Collector to Base Voltage: Vcbo = 1500 V
2. Collector to Emitter Voltage: Vceo = 750 V
3. Emitter to Base Voltage: Vebo = 6 V
4. Collector Current: Ic = 12 A
5. Collector Dissipation : Pc = 60 W
6. Junction Temperature: Tj = 150°C
7. Storage Temperature: Tsg = -55 ~ +150°C
Applications:
1. High Voltage Color Display Horizontal Deflection Output