Hi all,

New drone builder here.  I've been making solid progress and finally got to the point of plugging into Betaflight to do some configuration and testing.  When I first plugged it in, everything seemed to work correctly.  The blue and green lights on the FC flashed and the port showed up in Betaflight and I was able to connect.  I backed up the firmware as I was going to upgrade it at some point.

I decided to test out the motors so I grabbed my 4S battery and plugged it in.  The lights changed to just a solid red light and it lost connection to Betaflight.  The TBS CRSF Nano did power up when connecting the battery and was flashing green (guessing wanting to bind).  I unplugged the battery and USB the tried just USD to Betaflight and the solid red light just comes back on with no port showing up.

Did I fry the FC?  I only learned of smoke stoppers after researching this.  I didn't smell anything and don't see any obvious signs of a fried chip or anything.  I can't find any info no the Lux docs about what a solid red light means.  I also tried holding down the boot loader button when plugging in to the USB but still get the same solid red light and no new ports.

Here is the FC and ESC I'm working with:

https://www.getfpv.com/lumenier-lux-f7-u...gyros.html 
https://www.getfpv.com/holybro-tekko32-3...s-esc.html

Thanks for any suggestions.

The LEDs can mean different things on different boards. The red LED "usually" means that there is 3.3V on the 3.3V. If that is the case then it also means that 5V is getting to the board because the 5V gets stepped down to 3.3V for the MCU. This is backed up by the fact that your Crossfire Nano RX is powering up because that takes 5V from the 5V rail on the FC.

Assuming you're using Windows. when you connect the USB cable with the boot button pressed in, what do you see in Windows Device Manager? If you see nothing then check the solder joints on the USB connector of the FC because it's possible that you have some dry or cracked joints. If you're not sure then use some flux and re-flow the solder on each of the 5 USB pins and also on the USB socket chassis legs that usually connect to ground.

(12-Jan-2020, 02:42 PM)SnowLeopardFPV Wrote: The LEDs can mean different things on different boards. The red LED "usually" means that there is 3.3V on the 3.3V. If that is the case then it also means that 5V is getting to the board because the 5V gets stepped down to 3.3V for the MCU. This is backed up by the fact that your Crossfire Nano RX is powering up because that takes 5V from the 5V rail on the FC.

Assuming you're using Windows. when you connect the USB cable with the boot button pressed in, what do you see in Windows Device Manager? If you see nothing then check the solder joints on the USB connector of the FC because it's possible that you have some dry or cracked joints. If you're not sure then use some flux and re-flow the solder on each of the 5 USB pins and also on the USB socket chassis legs that usually connect to ground.

Thanks for the quick response.  It does say 3.3v on the board next to the red LED so I think you're right there. 

I'm actually on a Mac so not sure exactly what to check though I can confirm no devices are showing up in Finder like you might normally see when a USB device is connected (not sure if it was there when it was originally working or not).  I tried reinstalling the CP210x drivers but that didn't make a difference either.   

I'll take a closer look at the USB connection points but they look tiny and really hard to get to due to the chip right next to them.  

Thanks.

OK, I won't be able to help with diagnosing serial port connections on a Mac because I don't use one. Someone else might be able to help you with that.

It sounds like you're probably and Apple device user so you've most likely got an iPhone, but another thing to try if you happen to have (or have access to) an Android device then install the SpeedyBee app from the Google Play Store and connect an OTG cable between the Android device and the FC. There are no driver issues to worry about when using an Android device as it "just works" as long as there isn't a problem with the USB socket or the FC. If you've no heard of the SpeedyBee app before, it's essentially a full blown version of Betaflight that runs on a mobile device.

Ah, thanks for the tip. I do have an old Android phone laying around so I'll try and give that a shot as another test.

The Mac should just connect to the FC without any driver installation. Sometimes you need to select from the upper right the path with USB.

When you hold down the boot button and plug in, do you see DFU in upper right? If yes, then try reflashing the firmware.

Nope, I don't get the DFU when holding down the boot button and plugging it in. It also doesn't add the option for the "usbmodem" port that showed up initially when it worked.

My old android phone seems to be busted so haven't been able to test SpeedyBee app yet either. I'll keep debugging and maybe order a second FC to test with to rule out things.

(13-Jan-2020, 07:22 PM)homesteader_tim Wrote: Nope, I don't get the DFU when holding down the boot button and plugging it in. It also doesn't add the option for the "usbmodem" port that showed up initially when it worked.

My old android phone seems to be busted so haven't been able to test SpeedyBee app yet either. I'll keep debugging and maybe order a second FC to test with to rule out things.

Is it within 30 days of purchase. I would contact the vendor for a replacement. But can you also try a different USB cable? Also inspect the USB port to make sure the pins are not bent.

My USB port pulled away from the board. It was intermittent connection after that. They said at GETFPV that was unusual for Lumenier board to do that and try to reflow the solder. Very tight I couldn't do it so they replaced the board.

Double check that your USB cable transmits data as well as power. Many micro usb cables only do power for charging. One way to check is to plug your transmitter into your computer and confirm you get stick movements in a sim.

If it does and still nothing, make sure to install both the STM32 and VCP drivers (links on betaflight splash page), and try the ImpulseRC Driver Fixer.