bGeigie Nano won't charge, problem on FIO?

[Louis Bertrand]

Hello,

I am helping three friends build their bGeigie Nano kits and two of the kits won't charge. I have my own as a reference (assembled in 2013 and working well). We traced the problem to the FIO printed circuit board. The simplest explanation is that the USB connector pins are not making contact with the PCB copper pads on two of the FIOs. Unfortunately, the FIOs are already soldered to the main boards so there's no way of getting a soldering iron onto the gullwing pins to reflow the solder onto the pads. I've seen this before in SMT electronics, where there was insufficient solder paste or incomplete reflow. Or maybe it's the connector itself.

Observations (using a benchtop 4 1/2 digit meter, values rounded off):

• Healthy Nano:
  
• VBAT 3.6V
• While charging: USB VIN 4.73V, Battery + 4.07V 
• Won't charge Nano:
  
• VBAT (power off): 3.79V; (power on without iRover + tube) 3.78V
• Plug in the USB cable and meter the USB VIN+: 0.0055V
• Touch a +5V regulated bench supply to the CHG+ test point: LED lights up and VBAT=3.9V

I'm looking at the Eagle BRD file (Arduino-Fio-v23.brd from Sparkfun) and there really isn't anything between the connector and the test point. The trace seems wide enough that it shouldn't have a break. 

I noted that there is an earlier post suggesting that USB chargers need to be hand picked for a high enough voltage to trigger the battery management charge cycle, but this is not the case here: there is zero voltage on the CHG+ pin, USB charger plugged in or not. 

May I also suggest adding a step to the assembly instructions to test the charging (yellow LED turns on) before soldering the FIO to the main board.

Any suggestions?  I'd really hate to desolder the FIO (I have access to a decent quality desoldering pump but I worry about damaging the pads). 

Thanks

 --Louis

Louis Bertrand

Canada

[Rob Oudendijk]

Louis,

Sorry to hear about the issue. Any idea of how it happened?

A suggestion is to take the FIO out and resolder the USB connector. I know it is a hassle.

regards

rob