所谓显像管衰老,是指其阴极发射电子的效率降低,从而影响图像再现.甚至不能收看.用下面的方法可以准确地判断显像管县否衰老.1.测量阴极电流:将万用表150μA量程档串入阴极回路,开机后调整亮度电位器,阴极电流约在10～150μA范围内变化为正常;若亮度电位器调至最大,阴极电流却小于30μA.说明显像管已明显老化.2.测量电阻法:将显像管灯丝(阴极)加额定电压,其他电极全部悬空.万用表置于R×1K档位,用红表笔接显像管阴极,黑表笔接栅极,利用表内电地给栅——阴极之间加一个正向电压,促使电子形成回路.这时所测得的电阻值越小,说明阴极发射电子的能力越强,屏幕也越亮.一般情况下,电阻值R小于10KΩ,说明阴极发射电子的能力较强;若R为10～100KΩ,则表明管子已明显老化.对于衰老的显像管,只要不是因慢性漏气而造成的,均可用激活法使其再延长一段使用寿命.上述检查方法也同样适用于彩色显像管,只是要对应三个阴极分别依次检测,而彩色显像管衰老时的栅——阴极电阻值可高达200KΩ以上. The so-called tube aging refers to the cathode emission of electrons to reduce the efficiency, thus affecting the image reproduction, or even can not see the following method can accurately determine the tube age or not .1 .Calculation of cathode current: multimeter 150μA range file into the cathode Circuit, adjust the brightness potentiometer after power on, the cathode current is about 10 ~ 150μA range changes to normal; if the brightness potentiometer is adjusted to the maximum, the cathode current is less than 30μA, indicating that the picture tube has been significantly aging .2. Measuring resistance method: Filament (cathode) plus the rated voltage, the other all the electrodes dangling. Multimeter placed R × 1K stalls, with the red pen then cathode tube, black pen connected to the grid, the use of table power to the grid - plus a positive cathode The voltage to promote the formation of electronic circuits at this time the smaller the measured resistance, indicating that the stronger the ability of the cathode electron emission, the screen is also brighter.Generally, the resistance R is less than 10KΩ, indicating the ability of cathode emission electrons than Strong; if R is 10 ~ 100KΩ, indicating that the tube has been significantly aging.For the aging of the picture tube, as long as not caused by chronic air leaks, can be activated to make it to extend its service life. The inspection method is also applicable to the color picture tube, but to the corresponding three cathodes were detected in turn, while the color CRT aging gate-cathode resistance can be as high as 200KΩ.