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故障现象: 真空抽不上,开机后抽真空阀乱跳。检修过程: 打开仪器面板、发现PB418·42EVAC SEQH线路板上有严重的漏液现象,且一开机此板上有打火现象(部分线路图如图所示)。经查,为该板上C_1、C_2,二电容内的液体流出引起打火所致。拆下这两个电容,经查已失效。由于该电容为耐高压电容(0.05μ、4kv),国内市场上一时无法买到,考虑到请日方维修费用太高,后请上海无线电六厂特为我们生产10个电容(0.047μ、4kv)将线路板擦干净,取二个新的电容装上后,开机;首先听到蜂鸣警告声,经查,发现系循环水太少所致,加水至要求的循环水量,仪器开始按常规抽真空仪器抽真空进行一会儿后发现低真空能抽上,P_(i-1)、P_(i-2)均正常,但高真空指示灯不亮,且指针向右打到底(即无指示)。镜筒真空度是否已达到高真空还无法断定,这有两种可能:一是真空度低、二是高真空显示部分故障。若是真空度低,则有可能是下列原因所
Symptoms: the vacuum is not enough, after the start pumping vacuum valve bounce. Maintenance process: open the instrument panel and found PB418 · 42EVAC SEQH circuit board has a serious leakage phenomenon, and a boot on this board there is a fire phenomenon (part of the circuit diagram shown). The investigation, for the board C_1, C_2, two capacitors within the liquid caused by sparking caused. Remove the two capacitors, the investigation has lapsed. As the capacitor is high voltage capacitor (0.05μ, 4kv), the domestic market temporarily unable to buy, taking into account the cost of repairing the Japanese side too high, please Shanghai Radio Six Factory specially for our production of 10 capacitors (0.047μ, 4kv ) Wipe the circuit board clean, take two new capacitors installed, the boot; first heard the beeping alarm, the investigation found that the Department of circulating water too little due to add water to the required circulating water, the instrument began to conventional pumping Vacuum instrument vacuum for a while found low vacuum pumping, P_ (i-1), P_ (i-2) are normal, but the high vacuum indicator is not lit, and the pointer hit the end to the right (that is, no indication). Whether the vacuum tube has reached a high vacuum can not be concluded, there are two possibilities: First, the vacuum is low, and second, part of the high vacuum display failure. If the degree of vacuum is low, then there may be the following reasons