Common troubleshooting of multimeter resistance range

If there is a problem with the resistance range, first check whether the battery is normal. Because when the battery voltage is lower than the normal working requirement of the instrument, the multimeter cannot be adjusted to zero, which will naturally affect the accuracy of the measurement. Sometimes, after installing a new battery and not measuring anything, when measuring a few days later, it is found that it cannot be adjusted to zero, and the measured resistance value is obviously inaccurate. This phenomenon is mostly caused by the humidity in the space, and mold spots that are difficult to distinguish with the naked eye appear on the two metal poles of the battery. At this time, just take out the battery, wipe the two poles of the battery with a dry cloth, and put it into the meter for normal use. Another situation is that the weather is too cold and the battery voltage is close to the minimum working voltage of the multimeter. The above problems are also prone to occur.

If the multimeter still cannot be adjusted to zero after the above method, it may be that the reeds at both ends of the battery box are rusted, or the contact resistance of the range selection switch is increased. The repair method is to gently polish the rusted part with sandpaper to reveal the original metal luster. For the contact parts on the range selection switch, you can wipe them clean with a white cloth dipped in alcohol, and then apply a little "Vaseline" on the fixed and moving pieces.

Sometimes, the pointer of the meter is found to be unstable during zero adjustment. This is usually caused by poor contact of the zero adjustment potentiometer.