MCH-108 Digital Multimeter Repair

This Digital Multimeter model IF145-035-7 is sold by iFixit. A multimeter (also called a multitester a VOM or volt-ohm-milliammeter) is an electronic measuring instrument used to measure the voltage, current, and resistance of a circuit. Analog multimeters use a microammeter with a movable pointer to display readings. Digital multimeters (also called DMM or DVOM) either use a graphical bar representing the measured value or have a numerical display. Multimeters can be hand-held devices for field and basic work or bench instruments that can measure voltage, current, and resistance.

Multimeters generally include a display (either analog or digital), a selection nob, and ports. The selection knob allows users to set the multimeter to read milliamps (mA) of current, voltage (V), and resistance (Ω). Two probes are plugged into two of the ports on the front of the multimeter. The COM (common) port is generally connected to the ground or ‘-’ of a circuit. COM probes are usually black by convention, but there is no difference between red and black probes except their color. The 10A port should be used when measuring currents larger than 200mA, and the mAVΩ is the port that the red probe is traditionally plugged into.

• MCH-108 Digital Multimeter Product Page
• Wikipedia: Multimeter
• SparkFun: Multimeter Usage Guide