故障一:开机“三无”,并屡烧“行管”。分析检修:接修之前被告知,“行管”V406、“行变”T402已换过。开机测+B(130V)为零,断开L806,用100W灯泡作负载,开机+130V正常。测量“行管”已击穿,经检查确认只有行管损坏。换上一只新的“行管”后,开机光栅正常,半分钟后,光栅逐渐缩小,一分钟后又变“三无”。测“行管”又被击穿,触摸行管散热片异常烫手。屡次引起“行管”击穿主要有以下几个原因:(1)行变短路;(2)+B电压 Fault one: boot “three no”, and repeatedly burned “governed.” Analysis and maintenance: Before being repaired, it was informed that the “control” V406, “change” T402 has been changed. Boot test + B (130V) is zero, disconnect the L806, with a 100W bulb for the load, the boot + 130V normal. Measurement “line control” has been punctured, after inspection confirmed that only the line control damage. Put on a new “governed”, the boot raster normal, half a minute later, the grating gradually reduced, one minute later changed to “three noes.” Measured “in charge” has been broken down, touch the heat pipe unusual hot. Repeatedly lead to “governed” breakdown mainly for the following reasons: (1) line short circuit; (2) + B voltage