Re: HP35S ASSEMBLY METHODS Message #2 Posted by DaveJ on 16 Sept 2007, 5:11 p.m., in response to message #1 by designnut
There is nothing unusual at all here. The chip is most likely mounted using COB (Chip On Board) bonding technology covered with the black potting compound, a very common technique to lower cost in higher volume products.
The "vanishing" tracks are just an illusion caused by light reflection off the gloss black solder mask.
Interesting that they have chosen to use a hand soldered watch crystal rather than a machine assembled surface mount package, they probably saved a cent or two here, but it requires two extra human operations (solder+red blob)
Dave.
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