arty s7-50 board turned of suddenly and 3.3v power supply was dropped

[BALA]

we are using arty s7 50 board from 3 months while testing with the board suddenly board was off and it is not detecting with USB we checked the power supply it was dropped to 24 volts what may be the reason for that please support us in finding the cause for that 

[Bianca]

Hi @BALA,

Can you please give me more details with the work you were doing when the board shut down? Were you using external devices on the IOs? I need details like, was the board powered just with usb or through AUX? Were you touching the board at that point?

You said you checked the PS voltage drop to 24V... This is confusing... You meant 2.4V? Where did you measure?

Is the board not functioning just with USB or also with AUX?

If you tried just using the USB, is it possible to power it through AUX as well and see of it works?

Can you please measure some voltages on the board? 

If you power through aux: C137 , C144 (they are both near the power Jack)

If you power through USB: C146 (see the marking below TX LED, below USB)

In the same area around IC11, please also check the voltage on : C124, C127, C120

If one of those fail to provide any voltage, please turn off the board and check for short circuit on the rail. 

 

Thanks,

Bianca

[BALA]

we are checked with both AUX and USB power supply, we are getting 2.4 V at 3.3V stage. we measured resistance of 3.3V with ground is 0.5 ohm. do we need check any thing other than these. can we make it work again by making any changes in board components like capacitors, resistors 

[Bianca]

@BALA,

Well, you seem to have a short circuit to the 3V3 rail. I don't know if all the others are functioning well. If you can find the short circuit and remove the component that's causing it and replace it with another one, your board should work again, if the other rails are fine. Check the schematic for the 3V3 rail and try to look at the board. Maybe there is a component (capacitor/resistor) visible burned and you can remove it.

Bianca