How to judge the aging of color picture tube with multimeter
Apply 6.3V AC voltage to the filament of the color picture tube and leave the other pins empty. Take the selector switch to R×100Ω, connect the black and white meter to the modulation grid (generally grounded), and connect the red meter pens to the three cathodes of red, rate and blue respectively, and measure the resistance value. If the resistance value is between 1kΩ and 4kΩ, the color tube is normal and not aging; if the resistance value is between 4kΩ and 10kΩ, it means that the color picture tube has been aging, but it can continue to be used for a period of time; if the resistance value is greater than 10kΩ, then Indicates that the color picture tube is seriously aging, and the cathode emission capability is greatly deteriorated, so it should generally be replaced. For color picture tubes that have been aged or aged heavily, the method of increasing the filament voltage can be used to continue to use. Generally, a resistor of about 2Ω is connected in series in the filament circuit of the color picture tube. Adjusting the resistance value of the resistor can change the voltage of the filament.
