Repair the following places;
1, first measure whether the TL062 chip is stopped, if it is stopped to check the oscillating circuit components, replace the TL062 dual op amp chip if necessary.
2. Check and measure the poor contact of the capacitor socket, then repair the yellow film of the socket or the existence of poor welding contact and so on.
3, check whether the yellow film of each range switch is off, resulting in an open resistance connected to the range switch, if this is the case, check the range switch and so on.
Beijing Haidian Huangzhuang, Zhongfa building has a multimeter repair.