At 04:25 PM 3/12/2010, Marechiare wrote: > > All of the items that are created millions in a manufacturing > > run are, if at all possible, done on a single sided PCB > > because it saves significant money over the entire batch. > >That's somewhat debatable point, for example modern low-budget HDDs >are created in tenth of millions and have a very small double (I >believe) sided PCB. Yep - horses for courses. What I mean by that is: as components become smaller and more dense, single-sided boards just aren't suitable and you see double-sided or 4-layer or 6-layer boards more and more often. But you have to realize that is a RECENT trend - starting with, I think, modern PC computers and their peripherals. The trend away from single-sided boards will continue just because modern technology demands more density. But that trend is NOT caused by anything related to the statement that you made: "Yes, you are missing that you are not allowed to solder perpendicular surfaces." It is that statement that I take exception to and it is that claim that I'd like to you provide links to standards that specifically make that statement. I'm a geeky kind of a guy and I tend to disassemble anything new that I purchase or am given - just to see what's inside. Mass-market consumer electronics items still use a LOT of single-sided PC boards. And, as Olin pointed out, the last automotive dashboard that I disassembled to repair was also a large single-sided PC board. Modern design engineers will use the least expensive technology possible to manufacture their goods. They will use double-sided or multi-layer boards if the design requires it. But they still use single-sided boards with through-hole component leads stuck straight through the board, then wave-soldered when appropriate. Those through-hole components are all mixed up with SMT devices these days, of course. And, often, lots and lots of wire jumpers just so that they DON'T have to go to a double-sided board. dwayne -- Dwayne Reid Trinity Electronics Systems Ltd Edmonton, AB, CANADA (780) 489-3199 voice (780) 487-6397 fax www.trinity-electronics.com Custom Electronics Design and Manufacturing -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist