If the rectified output voltage is normal after checking, we need to check the operating point in the circuit. For example, a transistor will have a certain working voltage between its collector and emitter. The polarity must meet the requirements to ensure that it works in the amplification zone.

When the rectified output voltage of the device is normal, but the output voltage regulation is abnormal, the adjustment tube and amplifier tube must be inspected. Check whether the capacitor is broken down or short-circuited. If it is damaged, replace it in time so that the power supply can return to normal.

If it is found that a transistor is abnormal, there may be two reasons. One is that the transistor is damaged, and the other is that the component is damaged. At this time, it is necessary to analyze according to the circuit schematic diagram to solve the problem.

The last step is to check the surface of the equipment, check whether the fuse is broken or loose, whether the terminal is short-circuited to ground and whether the voltage indicator is stuck, and whether the transformer has a moldy or burnt smell. Check to see if there is any obvious damage to the equipment.