Geeetech

I just received a Rev E Mightyboard and started to hook it up, I had the heaters, thermistors, the LCD with the SD card/keypad, and of course power. I turned on the power just to make sure the LCD was installed correctly and chip U5 immediately glowed on one corner (where pin 8 would be) and smoked bad, then C10 popped and glowed and smoked it black, then the main chip U4 started bubbling, all in less than 2 seconds.
Any idea what happened and is there any way this could be a factory defect? I find it hard to believe this happened when I just replaced a board using the existing parts. The power supply is 24volts just as a makerbot.
I have pictures although I'm not sure how to upload them.
Wizard Merlin

Hi,
We are sorry about to reply you late,There are two reasons may result the board burned.
1.Power supply is inverted.
2.A4988 driver is inverted.
We were sure that every board were tested, 24V voltage supply is OK.
Maybe you did something wrong with it but you didn't know.
Please contact our cumsumer service online and send some pictures about your board.