Unusual PCB solder defect

[djbird3]

 I was looking through some junk boards today for a part and noticed something unusual about the T-Con board shown below. When I grabbed the board a few of the parts just came right off like they weren't even soldered.  I started checking the PCB closer and noticed just about every part on the board could easily be knocked off the board including the 176 pin quad pack shown below.

I've worked as a Tech for over 25 years and have seen my share of cold solder joints and corrosion problem caused by capacitors but have never seen this kind of problem so I figured I'd post it in the forum to see if anyone else has come across this or could explain what caused this defect. A close inspection of the board reveals that somehow oxidation formed between the copper solder pads and the solder itself resulting in the bond between the two to be weakened but what would cause this?...I'm thinking bad solder paste or maybe impurities in the copper cladding but I'm just guessing.

~Don~

[marshallh]

Probably a combination of early, unrefined lead-free processes and nickel plating coming off the copper base. (ENIG)

[free_electron]

definately nickel peeling...
the board is clearly enig. the parts that fell off leave copper behind.

they may have had conatminated copper before they applied the nickel.

[nanofrog]

they may have had conatminated copper before they applied the nickel.

This is my suspicion as well.

[mertsok]

I have also come across this type of problem for the first time. Anyone encountered this type of problem before? I think this might be soldering process issues.

electronics assembly

[KJDS]

I've not seen bad nickel on a board before, but I've seen bad nickel plating on aluminium housings where the plating would just peel off due to poor process control at the plating shop.