How do you design these days?
in [Design]
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From: Michael A. Terrell on 1 Jan 2010 18:26 krw wrote: > > We had a Golden Retriever-Border Collie mix when I graduated from > college and moved to NY (my mother couldn't handle it any longer). And > we got a Golden in the '80s, when my son was young, and had it for 13 > years. Ours were far darker than Spef's, though. We'd get another > but it's difficult to travel when you have dogs. Cats are much easier > to take care of. Food and water and they can be left alone for > several days. http://www.grouchyoldcripple.com/archives/CatCarrier.jpg -- Greed is the root of all eBay.
From: Jan Panteltje on 1 Jan 2010 18:29 On a sunny day (Fri, 01 Jan 2010 13:20:59 -0600) it happened krw <krw(a)att.bizzzzzzzzzzz> wrote in <njisj5tsft0qulelhdpvnonsj1akrl6v8a(a)4ax.com>: >Why are pin numbers an issue? You never probe from the backside of a >board? The spatial transform is pretty ingrained in me and I spent a >decade doing processor design (no PCB stuff). Exactly same here, I can in my mind just flip mirror no problem.
From: Michael A. Terrell on 1 Jan 2010 18:29 Fred Abse wrote: > > On Fri, 01 Jan 2010 00:49:11 +0000, Jan Panteltje wrote: > > > It is 'bison kit', or translated 'Bison Glue'. > > What is the difference between a buffalo and a bison? > > <Spoiler space> > > You can't wash your hands in a buffalo. Wimps! You should try Gorilla Glue! -- Greed is the root of all eBay.
From: Raveninghorde on 1 Jan 2010 18:35 On Fri, 01 Jan 2010 13:40:38 -0600, krw <krw(a)att.bizzzzzzzzzzz> wrote: >On Thu, 31 Dec 2009 19:16:58 +0000, Raveninghorde ><raveninghorde(a)invalid> wrote: SNIP >> >>The current oven is made by TWS Automation in Italy and is pre RoHS. 2 >>guys can move it. >> >>http://www.zen88234.zen.co.uk/photos/tws.jpg > >Oh, a small thing! How many zones? Our current oven is five zones. >We're told we should have at least seven and preferably nine for RoHS, >where the temperature profile comes dangerously close to the maximum >the components can handle. The idea is to soak the board in five or >six zones, then spike the temperature in one or two. Balancing the >soak and spike gets iffy with only five zones. > From memory 4 zones. It was fine with real solder. >>It was OK after moving to RoHS but I am packing bits tighter and using >>larger SMT parts such as 12mm square inductors which suck up the heat. > >Whihc indicates to me (certainly not my area of expertise) that the >soak isn't getting it done. > >>I had a guy going through test failures today. I saw a big pile with >>the same fault. I was told the oven was killing SOT-223 transistors. >>First I had heard of it. Some one will die on Monday. > >;-) > >>When I found the LED problem all LEDs where replaced on existing >>boards, about 600. They are now put on by hand which is a PITA but I >>know they are reliable. > >That is one problem we haven't had. Sounds like your temperature >profile is way too high. We did kill aluminum capacitors at one time, >but fixed that by getting rid of them. I think the problem is inadequate pre heat. So the guys are pushing the temperature too high at the soldering stage. Unfortunately even that isn't enough to compensate for the poor pre heat. I just had to put my money on the table and replace it. The next step is to upgrade the pick and place. Even with second user kit that will be real money. The pick and places are again TWS Automation but we need better. 0603 is a struggle so I don't go below 0805 but more importantly more and more ICs are too fine pitch and now with Altera BGAs on the horizon... > >>Now I know I have boards out there with suspect transistors:( > >Not a good feeling. > >>I had to get LEDs put onto aluminium backed boards elsewhere as there >>was no chance of this machine coping. >> >>The new beast, 1.3 tonnes, is a second hand Ersa Hotflow-5 made in >>Germany and cost about twice as much for the new TWS one, �12k. >> >>http://www.zen88234.zen.co.uk/photos/hotflow.jpg > >That's more the size I'd expect. I don't recall what we're using. >Again, I'm not an IE. > >>Spec here: >> >>http://www.zen88234.zen.co.uk/hf5.pdf >> >>We had to upgrade ventillation and electrics for another �2k. > >AIUI, our line came with the building. ;-) We are seriously >considering a new oven because of our problems. I'm told that there >is all sorts of surplus equipment available out there. It's either keep the kit reasonably up to date or pull out of the game as far as I am concerned.
From: Joerg on 1 Jan 2010 18:56
Jim Thompson wrote: > On Fri, 01 Jan 2010 13:44:42 -0800, Joerg <invalid(a)invalid.invalid> > wrote: > >> Jim Thompson wrote: >>> On Fri, 01 Jan 2010 13:27:12 -0800, Joerg <invalid(a)invalid.invalid> >>> wrote: >>> >>>> Jim Thompson wrote: >>>>> On Fri, 01 Jan 2010 16:17:30 -0500, Phil Hobbs >>>>> <pcdhSpamMeSenseless(a)electrooptical.net> wrote: >>>>> >>>>>> On 1/1/2010 3:56 PM, Joerg wrote: >>>>>>> krw wrote: >>>>>>>> Why are pin numbers an issue? You never probe from the backside of a >>>>>>>> board? The spatial transform is pretty ingrained in me and I spent a >>>>>>>> decade doing processor design (no PCB stuff). >>>>>>> Until one fine day you have one of those Supertex high voltage chips. >>>>>>> Some weirdness happens on the prototype boards, must be a software >>>>>>> issue. It's always software. Has to be. Hmm, let's see how that looks on >>>>>>> the old breadboard. Grab probe, lemmee see, serial data out was, uhm, >>>>>>> umpteenth pin from upper left ... POP ... *PHOOMP* >>>>>>> >>>>>> How dull your life would be without fireworks, though. ;) >>>>>> >>>>>> Cheers >>>>>> >>>>>> Phil Hobbs >>>>> Indeed! I haven't had a "fireworks" event since ~1980. >>>>> >>>> That's because you are designing chips with your computation machine. >>>> Having your hands inside a unit with a monstrous transformer that let's >>>> off an evil TUNGGGG when turned on is a different ballgame :-) >>> (1) I don't go sticking my fingers where I can't see ;-) >>> >> Sometimes, man's got to do what man's got to do ... > > Unless I know what I expect to feel ;-) > >> >>> (2) I designed discretes until around 1995, no flames. >>> >> Yeah, but probably no high voltage or power stuff. > > 1977-1987 Almost ALL direct off-line switching power supplies. > Yeah well, you said you didn't experience a kablouie in 20 years. That's 22 years. >> >>> (3) And no reports of flaming failures of systems with my chips, since >>> 1980... and the 1980 event wasn't even a final chip, it was a >>> breadboard... but it WAS a doozy ;-) >>> >> Nothing like a nice big spark once in a while :-) > > GenRad sales department, to this day, claim I rigged the Kaboom (and > traveling flame front :-) to keep them from hanging around my lab. > How did you do the flame front? Oh wait, in this day and age maybe one should not divulge ... -- Regards, Joerg http://www.analogconsultants.com/ "gmail" domain blocked because of excessive spam. Use another domain or send PM. |