If you are looking at parts from Broadcom Limited’s HDSP-550x, HDSP-552x, HDSP-560x, HDSP-562x, HDSP-570x, HDSP-572x, HDSP-H15x series of 7-segment displays, you may discover that discoloration has appeared on the non-solder dip area.
Confirmed by the manufacturer, this product’s leadframe is platted with Silver Ag. The LED will be subjected to Tin solder dip at the spec of minimum 50mil below their stand off, as shown in the below image. Thus, it is acceptable if the discoloration was observed on non-solderable dip area as below, it would not affect the performance of the product.
See also
Solderability of Silver
Discolored Silver plating switches
Applicable part numbers
HDSP-5608
HDSP-5607
HDSP-5607-GH000
HDSP-5603-GH000
HDSP-5601-GH000
516-1215-5-ND
516-1214-5-ND
HDSP-5608-ND
HDSP-5607-ND
HDSP-5607-GH000-ND
HDSP-5603-GH000-ND
HDSP-5601-GH000-ND
HDSP-5621-GH400
HDSP-5621
HDSP-5623-GH000
HDSP-5623
HDSP-5621-GH000
516-HDSP-5621-GH400-ND
516-1218-ND
HDSP-5623-GH000-ND
516-1219-ND
516-2738-ND
HDSP-5701-GH000
HDSP-5703-GH000
HDSP-5701
HDSP-5703
HDSP-5721-GH000
HDSP-5701-GH000-ND
HDSP-5703-GH000-ND
516-2014-ND
516-2739-ND
HDSP-5721-GH000-ND
HDSP-5721
HDSP-5723
HDSP-5721-ND
HDSP-5723-ND
HDSP-H151
HDSP-H153
516-1210-5-ND
516-1211-5-ND