Fun with Lead-Free soldering

...never seen an ant, at work, anyway. Wasps/hornets, sure. A mouse or two, but that was six years ago when we "lived" by the loading dock.

--
  Keith

you do want it to work though, right ?

I often come across anti-ESD attitudes. Usually from people with a rather limited understanding of the potential effects of ESD, the worst of which is a noticeable reduction in lifetime - IOW failures that crop up after some time, rather than outright deaths.

I once had a holiday job (1990) at a place that used a ceramic windowed

87C552. In one week my boss killed 10 of these parts ($200 each) because he was in the habit of carrying them to and from the programmer (in a carpeted office) in his hand. There were straps & mats at either end, along with bags, he just chose not to use them.

I have also had a smps controller expire due to static - boss gave a show-and-tell to some visiting guests, picked up my fully working smps and waved it around for about 10 minutes, before passing it to the group to be handled. I came back a few hours later, went to do some work only to discover it had shat itself. Luckily I soft-started the smps (provide external startup supply, check waveforms, slowly ramp up impedance limited HV supply etc), so found the problem, which was the UC3842 output stage, shorted *on*

Had I just flicked the switch, ka-boom.

static damage falls in the general category of "totally unnecessary mistakes to make"

Cheers Terry

LD50 is basically useless, for pretty much that reason.

What a brilliant idea for cleaning up a keyboard!

--
~ Adrian Tuddenham ~
(Remove the ".invalid"s and add ".co.uk" to reply)
www.poppyrecords.co.uk

LOX + LH2 has a specific impulse of something like 400 seconds, as opposed to LOX + RP (refined petroleum) of ~260 seconds. The additional weight of the 'C' doesn't help. The LOX needs a bit of cooling anyway, so...

--
  Keith

Indeed - nice one Ken! I wonder how much weight they could have saved on the shuttle using a fuel that did not need to be cryo-cooled, seriously pressurised etc. Not to mention what happens with ice formation on the tank.

Regards Ian

keith wrote in news: snipped-for-privacy@att.bizzzz:

We had a fire-ant invasion at the TEK field office in Orlando;when it rains,the ants look for "higher ground",and moved into a sump area in our wash room.

Florida and bugs....lots of them.

--
Jim Yanik
jyanik
at
kua.net

you too huh?

I have seen exactly that problem, on videogame logic pcbs. Between my

1st and 2nd stints at Uni I spent 3 years as a video game service tech. Absolutely nobody in the industry used antistatic anything - bubblewrap was the packaging of choice. A guy I know in Wellington switched to antistatic bags & handling, and saw his PCB failure rate halve. He then replaced all the cheap shitty smps with decent 300W PC supplies, and the failure rate plummeted to near zero - 1-2 PCBs per year, cf 1-10 per week.

Once I got my engineering degree I went to work for a power electronics company. We were pretty good with antistatic, but when we moved to SMT and the volume went up, our failure rate stayed constant, and became a problem. So we went to town on static - conductive jackets, the works - and watched the failure rate fall almost tenfold. designing products to greatly reduce handling also helped a lot.

even so, my first control board was susceptible to static. We used a Samtec bottom-entry connector on the control PCB, which had the PCB pins folded over the outside of the housing. This turned out to be a convenient handle, but one pin was directly connected to the micro. The first build of about 200 units had about a 10% failure rate on this pin, due entirely to static. despite foot & wrist straps, mats etc. I added ESD protection to the next run, and the problem disappeared completely. That was before the conductive jackets though.

It was important there, because zapping a $0.30 part could easily destroy $20,000 worth of power electronics.

yegods! betcha aint so happy about that nowadays.

Cheers Terry

Hello Keith,

No, if they flag it one has to stop it. Argueing with agencies usually doesn't work.

Well, this wasn't around here but in a university lab. At a university where I really didn't expect that.

While you and I like cleanliness others don't. In the end we'll all end up living with restriction because of the others. Such as not being able to walk our dogs around the local lake although ours never poop on any lawns. If they would, we'd clean it up right then.

Regards, Joerg

Not ISO-9000. THis is one place the victim gets to write the rules. If you did a bad job...

ISO in a university? What will they think of next? "No adult left behind"?

When I had dogs they pooped on my property. I now have a couple of cats that never leave the house, so when I got to the dump on Saturday... When I eat at my desk I clead up *my* area. ...though a vacuum would be quite handy, since "they" only do it every few months. :-(

--
  Keith

Lucky you! We get a few carpenter and scouts roaming through here at home too, though they don't live long when "outed". Eating at the desk isn't the cause of either.

No termites to be had here either. Do please do keep your pets down there! ;-)

--
  Keith