Views:77 Author:Site Editor Publish Time: 2020-03-09 Origin:Site
There are three main causes of the common problems of linear power supply.
A fault with no voltage output means that the power supply does not respond after starting up. First, check the output fuse of the power supply rear panel to see if it is burnt out. If the fuse has been blown, replace it with a new fuse of the same type. Turn the power on again. If the fuse is burnt again, it indicates that there may be a short circuit in the output circuit. At this time, the output switch of the output circuit should be checked. If the indicator light is normally lit after the power is turned on, adjust the voltage adjustment knob. If there is no response in the voltage indication and there is no voltage output, the position of the switch should be checked. The fault may be because the power supply is in the remote-control state. After the state of the power supply is adjusted to the local state, the power supply can restore the normal output state. If the potentiometer of the power output has been adjusted to the minimum, and the voltage preset is normal, and there is no voltage output in practice, the potentiometer of the current output should be adjusted appropriately to restore the normal working state of the power supply. Finally, check the output terminals JX1 and JX2 of the power supply to see if there is a short circuit. If there is a short circuit, the power supply will have no output. Check the output circuit of the power supply. When there is a diode short circuit in CR21-CR24, there is no voltage output from the power supply; replace the damaged diode in time.
For the unstable operating voltage of the DC stabilized power supply, if the indicator of the power supply is lit, the reading of the voltmeter is also normal, but the output voltage is unstable, and the working state of the auxiliary power supply voltage regulator should be checked. Check the voltage output and compare the operational status of the op amp and the current output to the op amp. Secondly, check the voltage output potentiometer to see if it works normally. After disconnecting the potentiometer circuit, check the resistance with a multimeter, and turn the potentiometer knob in turn, then the resistance value displayed by the multimeter should also be It is evenly changed, so that it can be judged whether the potentiometer is normal. When the output voltage needs to be adjusted, if the switching of the relay is abnormal, causing the output voltage to flash, the relay should be replaced and a new relay of the same type should be used.
The indicator of the power supply is normally lit, and its output is fully offset and cannot be adjusted. Use a multimeter to check the voltage of the output terminals JX1 and JX2. If the result shows that it is about 52V, you can preliminarily judge that the fault is open at the output end, analyze the output circuit, and adjust the tubes Q8 to Q13 to be parallel circuits. If more than one way When the adjustment tube is short-circuited, the entire control circuit will be ineffective, the output end will be open, and the output will be full-biased output, which cannot be adjusted. Use a multimeter to check the short circuit between the collector and emitter of the parallel regulator. If a short circuit occurs, it indicates that the regulator is damaged in the parallel circuit. At this point, each adjustment tube should be inspected, and the damaged adjustment tube should be replaced with a new adjustment tube of the same type.