electronics help

[Jester B]

I managed to find a spare airbag module for dirt cheap, but it does not work. My plan is to open it up and check all the solder joints to make sure there are no breaks. I only have a cheapo iron right now. What should I be looking for, and where should I look?

[R_Ethug]

Re: electronics help

brent or simon could probably fix if needed.. those guys can solder like nobody else

[RSS]

Re: electronics help

Soldering iron shouldn't matter as long as you have the right style and temperature of tip on it. I can solder just as well with a cheap $60 Weller as i can with the big $5k units we have at work.

More than likely there is a wire broken or a chip fried as solder generally doesn't break even when its a cold solder joint.

Don't forget to use flux and clean thoroughly after.

[Satnam]

Re: electronics help

I thought about helping, but then reconsidered due to liability issues.

[VAG_Tech]

Re: electronics help

I have 15+ years working with VW / Audi. IMO, Don't mess with airbags they KILL!!

[VWSM]

Re: electronics help

it's illegal.

[Jester B]

Re: electronics help

So, because VAG can't build a component that will withstand Canadian winters, I have to fork over a grand every year it so for another faulty part? That just sucks. Dave and Paul, I hear ya...thanks for the warnings around my safety.

[p951]

Re: electronics help

More than likely there is a wire broken or a chip fried as solder generally doesn't break even when its a cold solder joint.

I call BS. I have fixed numerous Porsche DMEs that failed with cracked cold solder joints. They all worked perfectly after that. I've also fixed my cruise control brain in the Porsche with bad cold solder joints. The vibration WILL cause cracks around solder joints on heavy components.

Just my experience.

[RSS]

Re: electronics help

What is a heavy component? if its so heavy why isn't it supported?

I build oilfield equipment electronic tools that go from -30C to +175C being shaking as it goes down hole and smashed at the bottom off the well and abused 95% of the time and i haven't seen any components break and fall off a board if that is happening they did some seriously shitty work.

[Boy Racer]

Re: electronics help

There is much you do not know (luckily for you, you haven't spent 15 years in electronics manufacturing and design for NORTEL haha)..Solder joints DO fail. All kinds of things can and do happen for which we send off to our crazy labs in Ottawa to investigate. Strange meterlurgic things happen that go way beyond "cold solder joint".

Gold imbrittlement?
http://www.sem-lab.com/GoldEmbrittle...lderJoints.pdf
A joint can become brittle simply because the gold plating used on some compenents, for varius reasons, causes a region where the metals are mixed in such a way as to cause a brittle material.

Electro-migration?
Defined as the enhanced (net) movement of atoms in the direction of the electron flow. In addition to thermal energy, electro-migration is an additional driving force for metal diffusion. Because of this, intermetallic formation, which is a typical diffusion controlled process, will be effected. Depending on the direction of the electron flow,
intermetallic formation could be enhanced or slowed-down. Due to uncompensated metalmovement, voiding will be induced at the cathodic side (entrance of the electron flow) and metal pile-up will occur at the anodic side (exit of the electron flow). Accumulation of voids can lead to an open joint or can facilitate crack growth which obviously deteriorates the mechanical integrity of the joint.

Tin whiskers?
Cool Nasa site.. http://nepp.nasa.gov/whisker/index.html
Tin whiskers are electrically conductive, crystalline structures of tin that sometimes grow from surfaces where tin (especially electroplated tin) is used as a final finish. Tin whiskers have been observed to grow to lengths of several millimeters (mm) and in rare instances to lengths up to 10 mm. Numerous electronic system failures have been attributed to short circuits caused by tin whiskers that bridge closely-spaced circuit elements maintained at different electrical potentials

There are more but you have probably all stopped reading already and got back to work for a good company

[RSS]

Re: electronics help

Not saying they don't fail but i am saying its rare for the solder to break usually something breaks away from the solder. I have had equipment that went from moving at 400m/min+ to 0 in a really short period of time as in hitting a cement bottom of a well when i crack open the tools i find parts broken off but where they came from the fillet is still there but it has actually broken the component apart and the ends are still soldered snugly in place.

It doesn't hurt that we use the Tin lead silver mix for our high temp stuff so its stronger then most of the solders out there.

But in my experience wires break parts fail 99% of the time those are the problems not a sketchy solder joint.

[Boy Racer]

Re: electronics help

You would doubtless see something different. High G and temps definately have a different failure profile to good old aging of mass produced circuit boards.

[Boy Racer]

Re: electronics help

PS.. can I have a job?

[RSS]

Re: electronics help

You would doubtless see something different. High G and temps definately have a different failure profile to good old aging of mass produced circuit boards.

Good point the oldest tool i have seen is probably less than 10years old and most sadly don't make it that long before they are KIA.

As for the job are you looking for Engineer, Technologist or Technician? and you do know I am in central Alberta not Calgary right?

[Stonewall]

Re: electronics help

I figured you where looking for work Simon I will let you know if I seen anything and if you let me know what you want to do I will ask around. As for the automotive type failures I have seen it is was mostly due to vibration of connectors where they would break the solder joint on the pcb and the contact would become intermittent. I have worked in everything from military to aviation and I have yet to see whole ic's fall off boards. I have seen pcb's where the gold didn't bond and after the boards where fully populated we could give them a little twist and all the components would fall off with the gold still stuck to the components, that was pretty neat.