The question was,

> What is the effect, if any, of 
> one of the four "spokes" going from a grounded pad to the clad area 
> being broken.

	IMHO, "it depends".  The reasoning behind the multiple spokes "used
	to be" allowing better chance of connection in the event of a single
	path being broken or blocked by proximity to other plane clearances
	etc.

	These days, you've got to look back to the technology of the elec-
	tronics.  If the connection happened to be part of the power/gnd
	system for a hairy-edged clock or high-speed network interface line,
	you *could* have trouble, depending on the amount of margin designed
	into the implementation (and who designed it ;).  Many of this genre
	of subsystem work "just barely" and degradation in this area could be
	a determining factor.

	Similarly, if the open occurred on the power distribution side of
	life, and the design was marginal to start with, you could introduce
	enough voltage drop to make a difference.

	You don't mention what the usage of the thermal relief is, and this
	could be a clue.  Very few parts of the performance level I'm speaking
	of are through hole, so if it's a DIP or discrete in all liklihood 
	you're "just fine".  If it's a power connector, large power component,
	clock generator, or network interface chip, you'd almost have to "try
	it and see".

	Perhaps you can get access to the folks who test the final PWA, they
	would probably have a feeling for how stable and robust the product
	is, if not the engineering group itself.  You may find other input to
	the class of design, such as whether the PWB is impedance controlled.

	Here's hoping it's a low- or moderate-performance product and you can
	avoid repairs.  Good luck!

	Regards,

        Jeff Seeger                             Applied CAD Knowledge Inc
        Chief Technical Officer                      Tyngsboro, MA  01879
        [log in to unmask]                               508 649 9800

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