Use a multimeter to detect the reason why the electronic platform does not display when it is turned on
1. If there is no response when the weighbridge is turned on with a black screen, it usually means that there is a problem with the power supply system:
1. Check whether the power supply is normal.
2. Check whether the power cord of the weighing indicator is connected to the power socket reliably.
3. Check whether the digital display tube of the weighing display is normal and whether the connection part is reliable.
4. Check whether the fuse of the weighing indicator is in good condition.
5. Check whether the power board is durable and of good quality.
6. Measure the 220V AC power supply with a multimeter to check whether the 220V power supply is normal. The normal range is 187V ~ 242VAC.
7. Check whether the power switch on the left side of the scale body is turned on
8. Check whether the fuse in the power socket is damaged.
9. Check whether the fuse on the switching power supply (16) is damaged
10. Unplug the DC power supply harness (18) at the main circuit board end, and use a multimeter to measure the voltage between pin 4 and pin 8 at the unplugged end of the harness (that is, between the red and black wires). The normal range is 24V±0.5VDC. If it exceeds the range, the switching power supply needs to be replaced
11. No display: If there is no display, first check whether the power supply voltage is normal, and check the voltage of pin 9. If it is abnormal, it is suspected that the IMP707 is damaged, and the instrument can work normally after replacement. If the meter starts beeping, but there is no display, use an oscilloscope to measure the strobe pin of the display chip. If there is no signal, the 74HC139 may be damaged, and it will be normal after replacement.
12. Unable to start the machine: Use the replacement method to find out whether it is caused by damage to the main board of the instrument. First, check the voltage. If it is abnormal, replace the 7808 and the voltage will return to normal. Use a multimeter to measure the short circuit between the input pin and the output pin of the 7808. After recalibration, the instrument will be normal. Can be normal.
2. If the indicator of the weighbridge is bright, then check whether there is a problem with the circuit or sensor of the weighing system, or it may be that the parameters of the instrument are lost, just re-calibrate.
