Power supply method adopted after the development of the image tube cathode and the filament ----- short circuit repair

The power supply method used by the developing tube cathode and the filament is shorted, the short circuit repair of the filament Keywords: filament short circuit processing method Author: Meng Qingyi In color TV repair, encounter the malfunction of the cathode and the filament of the color pipe. The brightness is full of control. The brightness is out of control. The row of suspension is used, which is full screen "rib strip"; power supply with switching power supply, manifested as full screen highlight Interference; use the city's electric step-down power supply, the image has a serious long tail; adding stream filtering is not effective. Later, the following measures have been made good results. Finding a cross section of 6mm × 6mm can be used, and the characteristic should be applied to the frequency of frequency, the volume is small. Re-use φ0.33mm enameled wire on both sides of the magnetic center (to be loosely coupled, in order to reduce The initial level distributed capacitor is each bypass 12, is made from 1: 1 transformer. Then separate the tube of the tube and the solder joint of the tail plate, and remove the copper foil around the filament pin. Guaranteed. The two sets of coils of the transformer are welded to the filament position of the developing tube and the filament pins of the image tube. The shorter the lead wire between the transformer and the filament, this is very important. This is very important. After the connection is finished, it will work for a while, hand touch the image tube filament Co-limiting resistor (pay attention to safety, turn off the TV or turn the current limiting resistance to the outside), see if the temperature rise is normal. If the humidity is obviously high, the number of transformers will be added to a few turns. If the image tube is started Time is much more slower than before, and the filament is appropriately reduced by the resistance of the wire current flow resistance. The author is changed for the fine-necked imaging tube. The filament current is 300mA. If it is another model of the image tube, consider increasing the magnetic core area of the transformer to increase the magnetic cross-sectional area of the transformer If the transformer is received without the transformer between the developing tail plate and the rear cover, the transformer can be placed on the other side of the tail plate. The above little experience does not exclude other methods recommended by the peers, this depends on the image tube cathode and filament Due to the extent of the breakdown. When the TV is working, there is more than 100 volts between the image tube cathode and the filaments. If the suspension is taken, there is no potential difference between the cathode and the filaments. As long as the cathode and the filament can ensure good insulation It is also possible to take other power supply methods.