I just spent an hour trying to find my dodgy pins, having refluxed and retouched every pin about half a dozen times. Visually they looked perfect (better than Marks', but I can say that because I don't have a camera capable of taking a nice close up )

Eventually I gave up being lazy, got the meter out and continuity checked each connection. There's enough room to get in there with the probes and test the top pin to bottom pin continuity. It only took me five minutes to verify all the connections and touch up the two that weren't good. Wish I'd done that to start with.