Teensy 3.6 dead - reballing?

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Pabloantxon

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Hi!
I have a Teensy 3.6 that I bought a while ago and used it for some tests, and have been sitting in a drawer until now.
When I connect it to a pc (tried on two pcs, windows and linux) it doesn't appear. The blink sketch is long gone so I can't use that for knowing if it works.
I saw on a thread in this forum that I should check the 3.3V pin and the Program and Reset pins. I get 3.3V on the three of them, and both Program and Reset pins go to 0V when I push the Reset button.
I just came across a thread in the Adafruit forum where someone says his board only works when pressing on the chip.
https://forums.adafruit.com/viewtopic.php?f=19&t=125796

I just tried it and it works. When I apply a lot of pressure with my thumb on the chip while connected via USB to my pc, the teensyduino sees it, but I have to maintain a lot of pressure.
The moment I let go a little bit the connection breaks.

Has anyone experienced this? Do you think reballing could bring the teensy back to life? what temperature and time should I try in that case?
 
These are unfortunately things which happen nowadays. Some thirty years ago, the same problems were caused by oxidized IC sockets. The question is if a $29 Teensy 3.6 is worth the effort, or if it's not cheaper and quicker to order a new one, depending on your personal hour rate.
 
Yes, I forgot to mention that I'm using it for a project that needs to be finished in two days, and here in Spain the spring vacations begin tomorrow, and ordering a new one I wouldn't get it until next tuesday or wednesday. I live in a small town and there's electronics shops that sell arduinos, but not teensies. That is why I'm considering reballing as an option :)
 
Don't forget that it could have been hit by static electricity. Did you store it in the anti-static bag?
 
Might as well give it a try, if you have the damaged Teensy and time to experiment. Sadly, I don't have any guidance, other than the general public info you'd find by google searching.

I can tell you we recently had a damaged Teensy X-ray inspected. It appears the customer inadvertently heated 1 corner of the BGA chip, probably will soldering the nearby pins and the soldering iron came into prolonged contact with the chip. Non-uniform heating of the BGA put a lot of lateral stress on the balls, due to thermal expansion. I know this probably don't help much if the board is already damaged with some of its solder balls no longer connecting - but something to keep in mind, you want to make sure the heat is applied uniformly.
 
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