Part 5: Phosphor Type The fifth symbol gives phosphor designation. The letter X here corresponds to P22 for colour picture tubes. Colour monitor tubes can have any other single letter (excluding I, O, or W) to designate other phosphor type for various applications. For monochrome pictures, phosphor symbol is WW, corresponding to P4. Monochrome monitor tubes also can use WW or some other two-letter combination (excluding I and O).

Part 6: Integral neck components The sixth symbol is assigned only for tubes having integral neck components, such as deflection yoke. The specs are only apply to a particular tube manufacturer. The primary consideration here is winding inductance. The yoke coils have different sensitivity i.e. deflection per Amp in both horizontal and vertical.

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Gain (hFE) – The replacement should have a gain equal to or better than original and it should be as close to original specification as possible.

Gain-bandwidth (fT) – replacement should have a transition frequency equal to or faster than original and it should be as close to original specification as possible.

Below is a table of application requirement and important specification that you can use for guidelines when comes to transistor substitution.

Application Requirement and Important Specifications 1. General purpose low level amplifier and switching transistors. Spec- hFE, IC (max), fT, VCEO 2. Power switching applications. Spec- VCEO, VCBO, hFE, IC (max), PD (max) 3. Low level IF/RF amplification. Spec- IC (max), fT, VCEO 4. Audio amplification. Spec- IC (max), PD (max), hFE, VCEO 5. High voltage transistors. Spec- VCEO, VCBO, IC (max), fT

Remember, replacement transistor should not run hot and if problem still persist, try another replacement number or get original number if possible. Do not overlook that surrounding components also may caused transistor to run hot even if original number is used.