Introduction to Common Faults and Repair Methods of Multimeters
1. The pointer swings abnormally, with intermittent oscillation and resistance
Solution:
(1) Open the watch case and use tweezers and a screwdriver to adjust the mechanical swing part, making the pointer swing flexibly;
(2) Re weld the header wire, reconnect the shunt resistor when it is disconnected, and replace it with a shunt resistor of the same model when it burns out;
(3) Use tweezers to readjust the shape of the balance spring, making its outer ring smooth and evenly arranged;
(4) Repair the supporting parts
2. No indication in resistance mode
(1) Reinstall the multimeter battery or replace it with a new one;
(2) Re weld the connection and adjust the center contact of the potentiometer to ensure good contact with the resistance wire;
(3) Clean the oil stains on the contacts and repair the contacts. If the welding connection wire is disconnected, it needs to be re welded;
3. When the probe is short circuited, the pointer cannot be adjusted to zero or the pointer swings back and forth unstably
(1) Replace with a new battery of the same model;
(2) Replace the series resistor;
(3) Adjust the socket spring to ensure good contact, and remove the oxide layer on the probe plug and socket;
(4) Clean the switch contacts of the multimeter with alcohol and calibrate the contact distance between the moving contacts and the stationary contacts;
(5) Use tweezers to press down the moving contact piece in the middle of the zero potentiometer to ensure good contact with the static contact resistance wire;
4. Resistance range is not connected or the error is too large
(1) Replace the resistor with the same resistance and power;
(2) Wipe and repair poor contact areas with alcohol;
(3) Replace the shunt resistor of this gear;
(4) Replace with a new battery of the same model;
