Instrumentation troubleshooting

1. The indicator light does not light up 1) Disconnect the power supply and check whether the fuse is in good condition? If the fuse is blown, it should be replaced; if the fuse is normal, check whether the power switch is in good condition? If the power switch is in poor contact, it should be replaced or repaired; if the contact of the power switch is normal with a multimeter, check whether the two input and two output terminals of the transformer have resistance values? If the measurement result is none 1. The indicator light does not light up 　　 1) Disconnect the power supply and check whether the fuse is in good condition? If the fuse is blown, it should be replaced; if the fuse is normal, check whether the power switch is in good condition? If the power switch is in poor contact, it should be replaced or repaired; if the contact of the power switch is normal with a multimeter, check whether the two input and two output terminals of the transformer have resistance values? If the measurement results are all infinity, it means the transformer is damaged and should be re-wound or replaced; if the measurement data is normal, check whether the rectifier bridge circuit is open and whether the connecting wires are soldered? If yes, re-soldering.　　 2) If the external 220V circuit is good, but the amplifier has no voltage output, it means that the amplifier is damaged and replace it.　　2. The deviation of the zero indication value is high or low　　 1) Adjust the resistance of the sliding wire, disconnect the power supply, loosen the screw of the sliding rod, fine-tune the position of the sliding rod, repeat the adjustment, and tighten the screw when the zero position is reached. Note: The screws must be tightened after each adjustment, otherwise it will automatically shift and cause serious imbalance. It is best to mark the position of the slide bar during the first adjustment.　　 2) Can not be adjusted to the zero position. If the power supply circuit is normal, it means that the bridge resistance is out of balance. It is necessary to check whether the bridge resistance has changed value or whether there is a short circuit in the components (between lines)? If so, you must re-adjust the bridge to balance it.　　3) The zero deviation cannot be adjusted. If the slip wire resistance is severely worn, replace it.　3. Indication deviation adjustment 　　 If the zero position deviation, adjust according to the method described in 'The zero indication value deviation is high or low'.　　 If the measuring range is wrong, just adjust the measuring range resistance.　　4. The indication is unstable and swings back and forth 　　 1) Check whether there is a break in the sliding wire resistance, and replace it if there is any. 2) If the amplifier gain is too low, increase the amplifier gain; if the gap between the cable reel and the roller is too large, reduce the gap; if the gear gap increases, replace the gear if it cannot be adjusted; if If the screws are loose, re-fix the screws; if inclusions cause the balance mechanism to be stuck in a certain position, carefully clean the transmission mechanism. Note: The power supply must be disconnected, and the drying process must be done after cleaning, and then power on for debugging.　　 3) If the filter capacitor leaks, the amplitude of the recording curve swing is small and has a certain rule, the filter capacitor should be replaced at this time. 4) If the external interference is large, for example, high-power motors or electric furnaces are often working in the surrounding environment, causing the instrument to jump irregularly and greatly in a short time, which will have a greater impact on the instrument with adjustment function. The stabilized power supply should also be shielded, and it is best to stay away from interference sources. 5) If the voltage-stabilized power supply is in poor contact or the measurement circuit, compensation wire, etc., the fluctuation amplitude is inconsistent. This phenomenon is generally related to vibration. It can be checked by knocking or touching the connecting wire. You must pay attention to it when checking. Safety.　　5. The pointer oscillates at the balance position and the recording curve is not smooth.　　 1) If there is dirt on the contact of the sliding wire resistance, it must be cleaned. After the drying process is done, adjust the position of the contact.　　2) If the amplifier gain is low, the mechanical gear and various connection gaps are too large, the gap must be adjusted to increase the amplifier gain.　　 3) If the filter capacitor leaks, replace it.　　4) If the external magnetic field interferes, the source of the interference should be eliminated.　　5) If the power supply is unstable and has great variability, use a power supply regulator to adjust the power supply voltage.　　6) If the vibration is large, keep away from the vibration source.