[Michele Soldi]

#3087

Hi, we were doing some power tests with the motherboard of the 5V printer via the 8 pin cable (it works very well) and in connecting it to the pc for programming my co-worker connected a 12V power supply to the STWI070WT-01 display with the 5V jumper soldered. After clicking the reset button on the board, the blue LED on the back of the display turns on, but the screen remains black. can something be done to fix it or is it to be thrown away?

Thanks

[Fiona Liu]

#3091

Why will a 12v power supply be connected to the display when you have to weld a 5v jumper it, you are to provide the screen how much voltage, if welding a 5v jumper can only provide 5v power, more than will burn the power supply circuit behind, you first check whether the power supply is correct, in addition to the CPU box circuit below the four groups of bare leakage test points, you can use a multimeter to test the leftmost group of 3.3v Test points, first test whether the short circuit and then test the voltage is normal, in addition to the back of the screen is two light-emitting led, please observe the led near the CPU is flashing, flashing that is the normal work of the system program

 

[Michele Soldi]

#3094

I tested the voltages, with the board powered at 5v, as in the image starting from the left here are the voltages I read:
1. -0.20v
2. -0.20v
3. 1.17v
4. 0v
5. 0v
6. -0.15v
7. -0.01v
8. 4.63v

with the card powered at 12v, as in the image starting from the left here are the voltages I have read:
1. 0v
2. 0v
3. 1.18v
4. 0.01v
5. 0.01v
6. 0v
7. 0v
8. 4.98v

the led next to the CPU does not light up in both cases

[Fiona Liu]

#3105

The place marked 2 in the figure should be 3.3v, is to power the cpu and other circuits, that circuit in the shield, it may be you solder 5v shorting point and then power the 12v voltage, which leads to 3.3v power chip burned, It may not be very easy to repair.

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