By the phenomenon known fault should be in the power supply itself or in the line scan circuit. First, add line electric logging output tube collector voltage, instantaneous about 40 V, then disappear. Off operation output transformer (4) feet, in the pipe pole connected to 220 V/c 60 w bulb false load, and electrical testing power groups' output voltage: 70 V, 56 V is normal. She c voltage measurement for 56 V, 13 V and end at about 11 V, 12 V - only - 10 V, 6.3 V end of about 5 V. But light bulbs will light up, and the voltage steady, conclude that line output transformer is out of order, after the replacement of line output transformer and electrical commissioning is normal.VTpservice manual download site