Nine precautions for repairing instruments:


1. When using a multimeter ohm block, remember not to measure with electricity.



2. When using a logic pen or an oscilloscope to detect signals, be careful not to allow the probe to touch both measurement pins at the same time, because the essence of this situation is to form a short circuit when the power is turned on.



3. When detecting the filter capacitor in the power supply, you should short-circuit the positive and negative electrodes of the electrolytic capacitor first, and do not use a test lead wire to replace the wire to discharge the capacitor when short-circuiting, because it is easy to burn the core wire. You can take a 220V, 60 ~ 100W lamp with a lamp head lead connected to both ends of the capacitor, and the bulb will flash at the moment of discharge.



4. When repairing instrument failures in a humid environment, it is necessary to test whether the various points of the printed circuit are smooth with a multimeter, because the main failure in this case is copper foil corrosion.



5. When repairing the internal circuit of the instrument, if the contact of the installed component and the circuit board are coated with insulating varnish, when measuring the parameters of each point, you can use a common hand stitch to weld the test pen of the multimeter to pierce the paint layer to measure each point directly There is no need to strip the paint layer over a large area.



6. Do not plug or unplug all kinds of control boards and plugs with power on. Because in the case of power-on, the insertion and removal of the control board will generate a strong induced electromotive force, then the instantaneous counter-voltage is very high, and it is easy to damage the corresponding control board and plug.



7. Don't knock and knock blindly during maintenance, so as not to expand the fault, the worse the repair.



8. When disassembling and adjusting the meter, the original position should be recorded for recovery.



9. When repairing precision instruments and meters, if you accidentally flick small parts, you should first judge the place where they may fall.



In short, in the maintenance of instruments and meters, first of all, you should understand the basic principles of instruments and meters, and master the knowledge and skills related to electronics, and you should prepare all the instrument manuals, drawings and other technical information, and should develop a Good working quality, thereby improving efficiency and reducing mistakes in the maintenance of instrumentation.