MF500B multimeter ohm file AC voltage file how to repair
The day before yesterday my MF500-B point resistor was mis-tested for 220 volts AC, and it just happened to be basically paired up yesterday. the RX1 was 9.4 ohms, with a 10 ohm and a 156 ohm (which is 156 ohms in series) in parallel, the total resistance was about 9.4 ohms, the RX10 was 91 ohms with a 100 ohm and a 1012 ohm (which is picked in parallel from 1000 ohms with a digital meter), the total resistance in parallel was about 91 ohms, the RX100 was 973 ohms, with a 3300 ohm and a 1380 ohm (which is 1380 ohms) in parallel, the total resistance was about 91 ohms. Ohms to pick the higher resistance) in parallel, total resistance in parallel is about 91 Ohms, RX100 is 973 Ohms, with a 3300 Ohms and 1380 Ohms (which 1380 Ohms through series), RX1000 is 33 kOhms, with readily available resistors.RX10K is 85.2 kOhms, with no burns. The easiest to burn are 9.4 ohms and 91 ohms.
Except for the meter head, which requires professional tools from a professional, the other parts should learn to fix themselves, and you can exercise your hands and brain. Why not!
My experience is to buy a digital multimeter and use it exclusively for testing mechanical meters and almost no other components, especially mains AC. Because now within 100 yuan of digital meter point resistance block accidentally misdetect 220 AC, on the reimbursement, it is difficult to repair, DC point resistance block the best 20 ohms, which can be used to detect the mechanical meter large current file. Such as 500-B range 5 amps file, its shunt resistance is 0.135 ohms. The DC current range should be 20 microamps or 200 microamps, e.g. the full bias of the 500-B is 40.5 microamps, and the full bias of the 500-B is 40.5 microamps.
There may be a problem with the meter head, as all the stops you described are not working with the head, approximating that not all stops can be damaged at the same time. You can find another multimeter, measure the 500B head is damaged (the head lead welded open to measure the internal resistance of the head), if the measurement of the meter reads, the measured needle deflection, it proves that the head is not bad, the rest of the work is to check the measurement of the subcircuit (voltage, current, resistance file) is damaged, the greatest possibility is also in series with the pen head line open welding .......
