Hello all, I am using Matek VTX FC HUB and F405 STD, while tinkering for new camera soldering unfortunately I got solder on FCC pins and it took me an hour to clean the solder bridges on the legs. 5v and GND was shorted and I did not notice it at first. When I connected lipo ESC got usual beeps but the FC Leds flashed once and no led on VTX. without FC the vtx and hub works.
Right now I managed to clean everything on FFC pins and no more 5v and GND short. with ribbon cable connected and receiver as well to FC. Receiver VTX ESC work but FC does not respond. I plug it to USB and no response as well but 2-3 legged probabaly voltage regulator got extremly hot and there was 3v3 GND short. I removed the really hot SMD component from the board and when I plug it to USB still doesnot turn on but nothing gets hot this time. There is still 3v3 GND short. But I am stuck unfortunately. can you please guide me ?

It might be worth you posting some photos of the component you removed. The Matek F405-STD FC doesn't have an onboard 5V regulator but it does have an onboard 3.3V regulator. There will also be a Schottky diode somewhere on the board to allow 5V input from either the 5V supply of the FCHUB-VTX board or the USB connection.

I don't know what component you removed but if it's not the 3.3V regulator chip then that might be why you still have a short circuit between the 3.3V pad and GND.

Hello, Thank you for your answer. I get in touch with MATEK support and they told me that;
"since you have removed the LDO chip,  not test continuity between 3v3 and G.
If there is continuity, MCU is dead.
If no continuity, replace the LDO chip"

The chip I removed is in the attachment. And as service suggested I tested 3v3 and Gnd continuity and there is still short there. It means MCU is unfortunately dead. I would like to get 30x30 FC suggestions though. Should I stick with Matek and get F722?

Assuming that you've already wired in the FCHUB-VTX and intend to continue using that integrated PDB / VTX with separate ESCs, you could try and get one of the Matek F722-STD FC's which will be plug & play with the FCHUB-VTX because it uses the same ribbon cable connection as the F405-STD. The only problem is that production of the F722-STD has been suspended due to the global chip shortage so you would have to try and track one down from a vendor who still has some old stock of them left. Otherwise maybe just get another F405-STD as a replacement if you don't want to disrupt your current installation too much.

Thank you. I bought another Matek FC as replacement. Talked with Matek service as well and they suggest me to replace MCU and it would probably work again. The problem is I do not know where can I buy individuell SMD chips like STM32F405RGT6. Do you have any idea where can I get one of these?

I'm not sure where you are based but you can get genuine (non-cloned) STM32F405RGT6 MCU chips from the reliable sources linked to below. Keep in mind however that there is currently a huge global chip shortage so the lead times on getting one might be a long time and/or you might have to pay a high price with no guarantee that replacing it will solve your issue. You will also need a hot air rework station if you don't already have one and be reasonably skilled at soldering / de-soldering SMD components.

• Mouser: https://www2.mouser.com/ProductDetail/ST...52Bfs8E%3D
  
• Digikey: https://www.digikey.com/en/products/deta...T6/2754208
  
• Newark / Farnell: https://www.newark.com/stmicroelectronic...32f405rgt6
  
• RS Components: https://export.rsdelivers.com/product/st...ex/7468217
  

Unless you have donor FC’s repairs involving MCU or Gyro chips or voltage regulators can take a while if waiting on parts.

I would suggest buying a replacement FC and keeping this in the parts bin for future use.