over-current problem stlink

[Kyrpav]

What can i do to fix the over current problem.i have a nucleo-F767ZI board and  it seems that by trying to power on a display there is a problem with the circuit at the backlight and now i get the LD5 for the over-current always on.

At this stage i do not care about the display at all i need to be able to make the nucleo work normally by it self without an display.

When i place power on stlink the over-current led is on and i can not connect to stlink with STMCubeProgrammer or with IDE.

What can i do to fix the issue to work again normally?

[TDK]

Remove the display?

[Kyrpav]

i removed the display it is not on the system, it was from the backlight power probably .nut the problem is there. you mean that the overcurrent will fixed if i take out what it is causing it? it can not be some permenant problem and i will have to replace something in the board to fix it?

[Tesla DeLorean]

Well if it continues it is more indicative of damage to the supply, regulation or IO pins of the STM32. Guess you'd start by measuring currents and checking voltages. Things you might have damaged, or shorted. 

Pull a schematic via CAD Resources tab.

[Kyrpav]

i got the schematics but from where to start? I suppose it is something from

this parts not from the real mcu. still i am in a not comfortable situation here. if something was to be burned what wound have been first in order the led to start light?

[Tesla DeLorean]

I don't recall what it is sensing, perhaps undervoltage. Start by following the current ingress pathways. Perhaps get a USB current meter and see if that's pulling excess current.

[TDK · Accepted solution]

If the display is gone and it still has an overcurrent condition, there's an issue with the board. Perhaps the STM32 chip itself is toast, perhaps another voltage regulator somewhere.

If something is drawing excess current you can usually find out what it is by feeling the chip that is hot, or with an infrared camera. The 3.3V regulator will likely also be hot but the issue is likely downstream of that.

[Kyrpav]

Probably i need more info. usb current meter needs to be pluged either in type c or usb port where nucleo has none of them but a micro usb. Even if this was not the issue placing the usb meter to the usb port of the nucleo not to the stlink usb how it is going to inform you what is pulling excess current ?

If you are talking for a multimeter to measure current you have to cut the line which can not be done in order to place the probes in each side

[Kyrpav]

i will probably by infiray p2 pro in general but i think i have found the problematic part by touching. The ST890CDR is burning. I need to buy new to replace it.

[leminhhuy]

I have the exact same problem. Replacement ST890CDR cannot solve the problem.

Have you tried? How do you solve it?

Thank you!