So,
The dead mini0806 (that stopped working after being dropped about 1m inside of the car) got a post-mortem...
Here are the pictures.
The last picture is interesting one....
Notice that there are pads missing I guarantee you that it wasn't my de-soldering (heat gun) or heat sink removal (other side would have pads missing otherwise).
My theory is following: because heat sink is glued between two different height, and BGA sized chips, with different operating temperatures, the temperature stresses would pull the BGA pad, hence the result. Initially it would probably make unreliable connection, while small drop would cause it come off completely.
This would also explain why 0805 is way more stable than 0806 (since 0805 does not have heat sink).
This also shows that when 0806 was designed, heat sink was last minute addition. If you look at IP cameras with a heat sink, there is never a heat sink on RAM, just on SOC.
I still have one mini0806 on my hands, it is a stable one, except battery is dead after just under one year of operation. Once I replace the battery I will split the heat sink in half on it to prevent the BGA failure.
This camera is great example of good idea and bad implementation. It also shows that Megtech does not have good engineering resource, and that there is disconnect between PCB designers, chassis designers and engineers, and absolutely zero testing.
I paid for this particular camera $120 USD, and for that money I spent $1000 USD equivalent of my time trying to solve these issues. Correction: I paid $120 for a camera that was crashing, I returned it to Megtech, which "promptly" sent me another camera with exactly same issue. It was obvious that they never tested the return.
The dead mini0806 (that stopped working after being dropped about 1m inside of the car) got a post-mortem...
Here are the pictures.
The last picture is interesting one....
Notice that there are pads missing I guarantee you that it wasn't my de-soldering (heat gun) or heat sink removal (other side would have pads missing otherwise).
My theory is following: because heat sink is glued between two different height, and BGA sized chips, with different operating temperatures, the temperature stresses would pull the BGA pad, hence the result. Initially it would probably make unreliable connection, while small drop would cause it come off completely.
This would also explain why 0805 is way more stable than 0806 (since 0805 does not have heat sink).
This also shows that when 0806 was designed, heat sink was last minute addition. If you look at IP cameras with a heat sink, there is never a heat sink on RAM, just on SOC.
I still have one mini0806 on my hands, it is a stable one, except battery is dead after just under one year of operation. Once I replace the battery I will split the heat sink in half on it to prevent the BGA failure.
This camera is great example of good idea and bad implementation. It also shows that Megtech does not have good engineering resource, and that there is disconnect between PCB designers, chassis designers and engineers, and absolutely zero testing.
I paid for this particular camera $120 USD, and for that money I spent $1000 USD equivalent of my time trying to solve these issues. Correction: I paid $120 for a camera that was crashing, I returned it to Megtech, which "promptly" sent me another camera with exactly same issue. It was obvious that they never tested the return.
).
