I faced problem over connecter's pin that were hot air soldered. This connector has 168 pins ( similar to the straddle connector ). The process is to apply the flux onto the connector's J-leads, and the hot air pencil were then ran thru' the leads to melt the pre-deposited solder ( attached to the connector ). Solder joints were perfect but there was a greenish colour residue built up after a few days on the unsoldered leads near the body. I suspect this came from the high soldering hot air temperature setting. I think this it is the copper oxided ( base matreial for the connectors are copper ). I'm not sure, when my customer told me that this could be a corrosion. Could any of you guys tell me what exactly is this greenish thing ? The flux we use is NR330 no clean.
Inputs are welcome.