Hmmm. I haven't seen that particular thing. 5V shouldn't short out the board. I suspect it blew a capacitor.
Years ago, we used to send warranty systems out to be repaired. About half of the systems came back, no problem found, and the shipping package had clearly never been opened. Another 20% came back opened, but the issues were intermittent, so a brief test would never find the issue. So, I had a thumb drive made that would build up enough juice to fry the board, leaving behind no visible evidence. The thumb drive was red, so we called it "red-sticking" the device. The 20% started getting fixed, but that left me with 50%. For every system sent back, we were charged a fee. I put the systems aside, and never processed the charge. For months, systems accumulated. I could never reach the manager of the service center. One day, he came to see me about the bill, so I showed him all the returned systems. I had him test the systems his people said had "no problem found". The manager was livid. System after system was completely inop. Now, he knew as well as I did that his people were just flipping a coin on which systems to check, but he sure did not like getting called out. Since the service center couldn't write off the charges, he had to personally cover the charges. I made sure he did, by having the charges redeemed at my location, and I rung up the "sale" myself. Only thing was, I billed him at double what they would have billed us, basically charging him for charging us. Something like $7K. The items were then shipped back to the service center at their expense. Problem solved. The regional service manager agreed to cover the difference for the customers to replace their computers. The $7K I dispersed as gift cards for the customers who had had to deal with the service center's issues.
