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RIP FEZ - or what happens when you over volt a USBizi


#1

Ever wonder what would happen if you applied say, 4.1V, to a USBizi-100? Let me save you the troubleā€¦sad thing is we burnt up two boards before we realized the problem :frowning:


#2

Wow! That is one fancy gadgeteer module!


#3

Ouch, that got tu hurt :confused: Is that a educational board or a commercial product ?


#4

I see Missouri S&Tā€¦ That must be a digital cow counter. :smiley:


#5

It is a custom board we did here last year for a research project. It was made to fit in a nice plastic case with the FEZ Touch screen on the other side.


#6

@ Mike - careful!

Marlboro man doesnā€™t mess around! ;D ;D


#7

So Missouri is associated with cows and cowboys ? :slight_smile:


#8

nah, that would be University of Missouri - Columbia. They have all the ag related studies and such. At S&T we are just a bunch of engineers (i.e. geeks.) :slight_smile:


#9

I think I see the source of the problem. You put the bizi on there crooked! :wink:


#10

Wow! Did it actually desolder itself from the board?


#11

No I desoldered the IC as I wanted to see how badly the board was damaged. A colleague has one of those fancy Pace 1700 SMD rework machines. The machine has a heating/vacuum had that is lowered down over the part and heats the part according to the profile set then holds onto the part with a vacuum nozzle and lifts the part from the board. Typically it works great, in this case a couple of the traces actually welded to the IC pins so the vacuum was not able to pull the part up. I had to pop the IC loose with a small wooden stick.


#12

We now have this board put up on the shelf as a reminder to do our power circuitry right the first time. :smiley: :smiley: :smiley:

I can also claim ownership for frying both boards, the first one went off out of nowhere, the next one went off right as I had the board connected to external power and USB. I saw a faint bit of smoke coming from the enclosure, and upon pulling the cover off, we were greeted with a decent sized mushroom cloud. It even singed part of the battery and left a big stain on the inside of the enclosure.