Grating dim as long as it is by the tube and the tube attached disorder caused by the circuit power supply voltage. Encounter this kind of situation, can use a screwdriver to adjust the brightness VR705 fine-tuning resistance, watch the grating brightness is back to normal. If not back to normal, then check the anode voltage and focus voltage and accelerating voltage is deviating from the normal (high voltage anode voltage normal 2 to 10 kv, focus on the anode voltage of 320 ~ 400 v normal, accelerating the anode voltage is normal for 240 ~ 240 v). If the voltage is not normal, should check VR704, R726, mainly R727, VR705, R728 whether open or damaged.Qcuservice manual download site