SMC 24v23 No Power (Vin or USB)

Hello,
I’ve been using a SMC 18v25 for years in my RC Power Wheels project and I ordered a pair of 24v23 boards for an upgrade. One of the 24v23s is completely dead and doesn’t power up via USB or the battery Vin pads.

Motor Setup:
Two stock 12v power wheels motors wired with about 18" of 10 gauge and XT60 connectors (yellow).

Battery Setup:
Three 6v 12AHr wired in series with 10 gauge wire. The final pos and neg terminals are split using 12 gauge wire and XT60 connectors (blue). All 3 batteries fully charge output no more than 18.5v.

What happened:
I needed to invert one of the two motor directions so I connected motors and VIN to each 24v23 and connected each board to laptop via USB. I had two instances of SMC Control Center running and began to move the slider for one board and then the other. I didn’t have “Return slider to 0” checked and when I moved the second motor the platform took off. I quickly disconnected VIN from one motor controller and then the other. The Jeep moved about 6 feet before I reacted and disconnected power.

After checking my settings in SMC Control Center I immediately noticed that one of the boards was disconnected from USB. I swapped USB ports, swapped battery power connectors, and swapped USB cables and I’ve got nothing. No lights and no response via USB or VIN. The board draws about 7ma when connected via VIN only.

I’ve attached 3 pics of the top and bottom of the board as well as the battery wiring.

Hello.

Your project looks really cool; thank you for sharing it with us.

I am sorry you are having problems with your Simple Motor Controller. Thank you for posting pictures. I do not see any visible signs of damage. From your description, I am not sure what the exact problem might be, but it definitely sounds damaged. When you connect power to the VIN pin, does the yellow indicator LED show any signs of life? When the Jeep moved while the SMCs were connected to USB, did the USB cable pull on the connector? Could you inspect the USB connector on the unresponsive board for any signs of damage that could be causing a bad connection? You might check to see if any of the pins inside the USB connector look bent as well.

-Brandon