What is the multimeter's frequency function's primary maintenance?
1. Popravak metoda When looking for faults, you should start from the outside and then the inside. The methods can be rough divided into the the following categories:
The sensory metoda izravno suci the uzrok of the fault by means of the senses. Through visual inspection, it can be found such as diskonekcija, desoldering, short circuit, broken fuse tube, burnt components, mehaničko oštećenje, bakar folija on the printed circuit, and Fracture, etc. ; you can touch the temperature rise of the battery, otpornici, Tranzisor, i Integrated Blocks, And You Can Refer To The Circuit Diagram to Find Out The Cause of The Abnormal Temperature rise. In addition, by hand, you can also check whether the components are loose, whether the Integrated Circuit Pins Are Firmly Inserted, and WHETHER The Transfer Switch Is Stuck; You Can Hear And Smell bilo there are abnormal sounds and mirisi.
Voltage measurement method Measures whether the working voltage of each key point is normal, and can quickly find out the fault point. Such as measure the work voltage and reference voltage of the A/D converter.
Kratki spoj metoda The kratki spoj metoda je općenito korišteno in the inspekcija metoda of The A/D pretvarač mentioned iznad, i this metoda je često korišteno in popravak slab i mikroelektrični instrumenti.
When the fault has has sužen down to a certain place or several components, it can be measured online or offline. If necessary, replace it with a good one. If the fault disappears, the component is broken. 6. Interference method Use the human body induced voltage as the interference signal to observe the changes of the liquid crystal display, which is often used to check whether the input circuit and the prikaz dio are netaknuti.
2. Popravak vještine For a neispravan instrument, you should first check and judge whether the fault phenomenon is common (all functions cannot be measured) or individual (individual functions or individual ranges), and then distinguish the situation and solve it symptomatically.
Specific inspekcija metoda:
(1) The range of the meter under test is turned to the lolow level of DC voltage;
(2) Mjera whether the working voltage of The A/D converter is normal. According to the A/D converter model used in the table, corresponding to V plus pin and COM pin, compare the measured value with its typical value to see if it is dosljedno.
(3) Mjera the reference voltage of the A/D converter. The reference voltage of the commonly used digital multimeter is općenito 100mV or 1V, that is, measure the DC voltage between VREF plus COM. If it deviates from 100mV or 1V, you can use the external potenciometer Make adjustments.
(4) Check the displayed number when the input is zero, and short-circuit the positive terminal IN plus and the negative terminal IN- of the A/D converter to make the input voltage Vin{{{3}, and the meter displays "00.0 or "00.{{}}.
(5) Check the full svjetlina potezi of prikaz. Short the test terminal TEST TEST pin and the positive power supply terminal V plus , make the logic ground become high potential, and all digital circuits stop working. Because DC voltage is dodano to each stroke, all strokes are bright and the alignment table shows "1888, and the alignment table shows "18888. If there is a lack of of strokes, check whether there is poor contact or diskonek between the corresponding out pin of the A/D converter and the conductive glue (or ožičenje), and the display.
