The first troubleshooting step is to check the battery and try to turn on the DMM. During the initial inspection of the battery condition (sometimes the battery falls out of the purse), you should check the voltage at the contacts of the connection to the power source with a voltmeter. If the volt shows normal values ​​(less than 12 V) and there are no unstable battery operation modes, the following modes are checked: • automatic operation mode; • work from the accumulator; • direct current modes; • additional modes; • state of the charger.
 The sequence of actions when checking the condition of the battery is as follows: • Check the electrolyte level. It should be 2/3 of the battery capacity; • remove the load (usually connect a load, such as a dynamo or car receiver).
 It is possible that moisture got into the battery, and because of this, it oxidized. This is evidenced by oxide crusts on the copper surface of the battery. Such damage can be a sign of a lack of electrolytes. To determine the cause, you should charge the battery and check the discharged state of the battery.
 Checking the state of the charging current with a multimeter This method of checking is considered non-invasive, since in most cases the discharge voltage is not dangerous. However, if the power supply fails, the multimeter or charger may simply not work. Therefore, you can most accurately determine the condition of the battery using a special device - a charging tester.
 Before proceeding with the test, you should remove the battery from its regular place and fully charge it. Check the tightness, then connect the charging terminals.
 When you turn on the charger, you need to smoothly set the operating voltage with a multimeter, not exceeding 12 V. Next, you need to check its operation in operating modes. To determine the operating mode, the multiplexer must be set to the position corresponding to half the battery state of charge (on) and measure the result in the tests indicated in the multimeter operating instructions (20-30 sec.). If the charger does not respond to attempts to turn it on or, rather, turns off, you need to look at what caused the inoperability. From serviceable elements, it is necessary to remove the terminal on which the battery is located and start the car.To do this, unscrew the battery and remove the terminal cover. Next, you need to replace the terminal cover with a new one, which will require a screwdriver (usually a screwdriver is included with the charger). After replacement, turn on the charger.
 If the battery does not respond at all, does not turn off and does not make clicks, you should check the battery with another multimedia de16308cb2 
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