Boot check, sure enough sound normal and adjustable size, but the screen is black. Open the cabinet, kinescope filament visible light, thought it was black screen common faults. Try to raise the accelerating voltage, until at the end of turn SCREEN potentiometer, still black SCREEN, neither dim image, no bright line or line flyback level. To measure the tail plate depending on the power supply voltage. 3 guns basic normal voltage. But the accelerating voltage is only about 6 v. Visible because of the accelerating voltage is too low. Brightness. So there is no image. CUpservice manual download site
 CUpservice manual download site
Because there was no this machine circuit diagram, shutdown, check the mainboard printed circuit directly, see the adults coil and share the bleeder circuit transformer output voltage is directly grounded. CUpservice manual download site
 CUpservice manual download site
 CUpservice manual download site
Header tail plate is measured with a multimeter high block of resistance for more than twenty megohm variable; Focus of resistance for one hundred dozens of megohm variable. FOCUS potentiometer turns to the largest, resistance than multimeter range. Show for infinity. Measuring accelerometers and the focusing electrode resistance, resistance is variable. But when FOCUS potentiometer to maximum, with FOCUS on high pressure cap resistance value between the circlip display for infinity. For multimeter Ω maximum range of 200 m, and the circuit diagram, I do not know whether normal, doubt is likely to be high voltage coil or partial pressure circuit open circuit fault, had to buy a new line of the output transformer substitution, can use the computer after the fault remains. Use the Internet, according to the practice, pull the tail plate, tube boot measuring acceleration voltage is 350 v. Fault should be in the tube. Shutdown, carefully measuring tube accelerometers pin with other electrode resistance. Discovery and the resistance between the grid only a few hundred thousand, it seems may be a touch or serious leakage. CUpservice manual download site
 CUpservice manual download site
To simulate practice, from the tail pipe seat plate will be removed and tube well, for a period of neon inserted with the high tension line in accelerating tube feet, roots with high-pressure tape wrapped to prevent the flames; In grid welding a conventional wire pin, the other end of the coil in the graphite layer braided line (line output transformer accelerating voltage fuses on the transom, focus voltage fuses with high-pressure tape wrapped hung up or on the dry glass jar). Tape to fasten on plastic insulating rod and high pressure cap leads to boot, the high pressure cap circlip slowly close to the speed in the high voltage wire. Appears near for the first time, a lot of pull arc spark; The second time approached arc spark has not obvious. Shutdown, measuring between accelerometers and grid resistance to infinity. After the commissioning of all circuit restoration, audio and video is normal, troubleshooting.

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