I was testing the HMGC5883L sensor among others on an AB WX. Everything bought new -unused.
Any power supply; multimeter; proto-board and whatever else used during the tests are OK.
Software was downloaded from the KickStart examples.
The first problem began losing the 3.3v rail on the AB WX board leaving it useless.
Next test was done using same sensor with a Propeller Mini and a bench power supply noticing, just after running the program, a drop in the power supply from 3.3v to less than 2.5v (at Vin, not at SDA/SCL) and 3.3v OK while doing nothing.
Disconnected from Propeller Mini and applied 5v to sensors Vin the HMC5883L IC “smoked” immediately. Power requirements for this sensor: 2.7 v to 6.5 v.
The resistance measured after that at Vin-GND was 5 ohms. After heating a bit the FAN2500S25X sensor´s regulator, resistance went up to 180 ohms -due its thermal sense or thermal compensation- and finally reaching down 110 ohms at ambient temp.
The FAN2500S25X is a fixed 2.5v reg.
Appling 2.7v at sensor´s Vin the reg.´s Vout was a bit more than 2.5v.
Appling 2.9v at sensor´s Vin the reg.´s Vout was a bit more than 2.7v!!!
Appling 3v at sensor´s Vin the reg.´s Vout was a bit more than 2.9v!!!
So at 5v?????
This means the sensor´s reg. is fried and when I had applied 5v to the sensor, it went over the ABSOLUTE MAX Vdd for the HMC5883L IC (4.8v), burning it.
After a close inspection of this sensor using a powerful magnifier, I saw LOTS of very little lead balls stuck between the components and board.
The same found on the AB WX board but bigger, especially under the caps and the bottom side of the board but that was not the real problem on the AB WX! A white paste was left, most of it all around the regulators zone. That paste turned greasy and hard to take it off. Under the zone in which paste was applied, some tracks darkened same around schottkys cathode pad.
The sensor triggered the problem on the AB WX board.
The board is working back without pulling a component but this means the board eventually will damage when copper of those darkened tracks decompose. Electro mechanical migration and moisture sensitivity level are two points to take in consideration when manufacturing.
Things happens and this was my turn.