On Oct 3, 2005, at 11:54 AM, Mark Scoville wrote:

>  We can't justify paying extra for electrical testing.

There's a third alternative of doing bare board testing on your side
of the manufacturing process.

I suspect part of the reason for not providing testing by default is
that customer "specifications" for testing vary a great deal.  There
is no data in the formats accepted by PCB vendors that say which traces
are supposed to be connected to each other (or not), so implementing a
test means transferring a whole new set of data, with room for errors
in the data and now a "you tested it but it still doesn't work; I'm not
paying!" sort of mentality from the customer.  ("oh, I guess I did 
forget
to connect the power supply to that one chip.  Never mind.")

The "cheap pcb" forum over on sparkfun.com is interesting reading.
Originally designed to offer hobbyists $2.50/in^2 PCBs on a "you
give us the files, we give you a matching PCB" basis, they ended up
having SO many stupid errors and questions that they had to double
their price just to pay for the time checking designs to make sure
they weren't obviously broken.

One likes to think that a PCB design is done, and you get the same
board matching your cad program from every vendor out there.  But 
there's
enough lack of standardization that this just isn't so...

BillW
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