Common faults and troubleshooting methods of grounding resistance measuring instruments are as follows:

1. The power indicator and the display are not on after the machine is turned on.

a) The fuse in the power socket is in poor contact with the contact spring and sheet. Replace the fuse or fuse holder.

b) The secondary AC9V of the power transformer is loose to the motherboard socket. Replace the plug tightly.

c) Test 7805 output should be 5V, if there is no voltage or the voltage is too low, check the related rectifier, electrolytic capacitor and three-terminal regulator.

2. No current.

a) Desoldering at the welding place of the test wire and the big alligator clip, poor contact or disconnection of the test wire, and "A", "a", "B", DC resistance rapid tester, "b" socket loose, broken, socket The wires and socket screws inside are not tightened.

b) "Measuring" switch is damaged, replace the switch.

c) The relay HG4130 on the SCR board (small board) is damaged. Replace the corresponding components.

3. Turn on the "Overcurrent" light on.

Return the adjusting current knob to the zero point, and then press the "reset" key.

4. If the "start" and "reset" keys of the instrument do not work due to serious interference or improper operation, you can press the "power" switch to turn off the power and restart the instrument, and the instrument can work normally.

5. If the above faults still cannot be eliminated or there are other faults, please contact our company.

6. The measured value has a large error, please check whether the compensation value is set correctly.