Kyosho Perfex KA-15L Brushed Electronic Speed Control

I recently switched from the stock 27MHz transmitter to a 2.4GHz transmitter. The moment I applied the throttle with the 2.4GHz transmitter, the esc started smoking heavily and the positive lead on the battery side unsoldered itself. After reattaching the lead the esc no longer had reverse. It seems to still be working in forward, but I imagine it's only a matter of time until it dies as well.

Since the smoke only appeared after pushing the throttle, and only one or two of the four bridge transistors are died (it still works forward), the battery polarity is correct, the motor is not short-circuited, and the malfunction is the result of null quality control. A damage caused by battery polarity reversal would have been immediate and deeper. It is a clear DOA.

The above review must have soldered his wires backwards and caused polarity reversal haha