Hi all,

I have a problem with my geprc F722dual.
USB is not working. PC not recognizing anything, FC is not powering on. But plug is getting warm/hot.

If I supply VBat over ESC the FC powers on.
or
If I supply 5v the FC is powering on.

Only USB seems to be defect.

The connector is good. There must be something broken on the FC.

I already did a research. Often it's a broken shut diode.
I only can find one of these diodes on the FC. Seems to be good.

It's there any solution? Maybe connecting to betaflight via UART. But therefore MSP have to be set to an UART.
This is only possible if I flash firmware to the chip.
I have a CH341a programmer, but can't find IO or clock pads.

What can I do?

Photos: https://photos.app.goo.gl/eZYYTR7MGjii1Zpr9

Best regards

I don’t have this FC so I can’t confirm if the CLK and DAT pads are broken out on the board. You can read the spec sheet for the STM chip and find which legs of the MCU are CLK and DAT, then test for continuity to the broken out pads on the board using a multimeter.

If the pads are not broken out on the board then you can solder directly to the legs of the MCU but this will be a delicate soldering job.

If the FC is already setup on the quad then why bother with so much hassle and you don’t necessarily need to update firmware every time. You can access most settings via the OSD menu as well.

Hello,
thank you for your reply.
This was a unconfigured spare FC and I wanted to built a new drone.

I found the pinout scheme of the Stm32f722.
Pin 46 and 49 are for debuging (ST-link)

What I measured:
If I plug in USB, I can grab 5V and 3,3V from the pads/pins. So Bec seems working.

But was I also recognized is that VSS and VDD on the STM32 have electrical continuity (1,3 Ohm).

There should be no continuity, correct?

Regards,
Harry

One of these diodes is defect.
https://photos.app.goo.gl/3Kr44DQuAbYKSmWT8

Does somebody know the type?
I can read BC t94

EDIT: should be a Nexperia BZT52H-C5V6. I ordered some and will give feedback.

Regards,
Harry

Not sure who on this forum will have this FC to confirm.

I will suggest you contact GepRC as they maybe able to give you exact details about components on the board.