Our school has a dead Bretford cart that manages 40 devices. Both drawers without power. Followed troubleshooting tips from company but no luck. Suggestions for repair or replacement?

I teach 7th grade social studies at a middle school in SC with 360 iTouches and more than 100 iPads. We use what I believe is the first generation Bretford cart to charge and sync groups of 40 (20 per drawer). At the beginning of the year one of our carts simply had no power to either drawer. I have followed the trouble shooting tips of plugging and unplugging power supply cables. I even replaced the main power supply cable with a cart that was functioning. The only "electrical" components appear to be where the USB cables gather inside the drawer and a junction box that splits the power for the two drawers.

I am looking for suggestions for repair or replacement.

The warranty is out on the cart and Bretford's suggestion is to ship it back to them. That does not make a lot of sense. Currently, I am using four brand new 12-port usb hubs to charge and sync our dead cart. But these have already started having issues. I am getting error messages that sycning and charging are not supported on the device.

Does anyone have any suggestions for either repairing the Bretford cart or a proven, reliable replacement?