Bob Ammerman escreveu: > ----- Original Message ----- = > From: "Olin Lathrop" > To: "Microcontroller discussion list - Public." > Sent: Thursday, March 12, 2009 5:10 PM > Subject: Re: [Bulk] Re: [EE] Fast, Cheap, and Good PCB manufacturer > > > = >> Isaac Marino Bavaresco wrote: >> = >>> I always request electrical test for boards with 4 layers and up. >>> >>> For boards up to two layers I agree that it is wasting money. I never >>> got a bad single or two layer board from the manufacturers. >>> = >> Then you've been lucky. I've had bad vias that looked good visually, >> hairline breaks in traces, and once even a errant finger of copper = >> shorting >> two unrelated traces. Life is too short to waste time on that stuff. $= 20 >> is worth not having the aggrevation, let alone the cost of diagnosing the >> problem, fixing the board, and possibly replacing components that got >> damaged in the process. >> = > > I would say he is very lucky. I've only ordered boards a few times myself = > and had a shorted trace (a big blob of extra copper) on a relatively simp= le = > 2 layer board. I hadn't specified testing, but luckily caught it with a = > careful visual inspection before loading the board. > > -- Bob Ammerman > RAm Systems > = Perhaps I am lucky, but really never got a defective board from the manufacturers. We usually order lots of 100 boards each time and most models are re-ordered regularly to replenish stock. Sometimes we receive panels with one or more boards marked as not approved in visual inspection (they stick a paper sticker on them before they print the solder resist, making the boards useless), but they don't charge us for those boards. On the outside of the package they put a green label saying: "Not electrically tested by customer request." Once I inspected the non-approved boards and found tiny porosity in a copper area, but electrically it was OK. If would we assemble the boards, I'm sure they would work (although with a ugly soldermask-less spot where the sticker needed to be removed. Regards, Isaac __________________________________________________ Fa=E7a liga=E7=F5es para outros computadores com o novo Yahoo! Messenger = http://br.beta.messenger.yahoo.com/ = -- = http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist