60hz hum

Nonwetting:a nonwetting solderability issue is when the solder does not "wet" or make a metallurgical bond with the surface you are trying to solder

Dewetting: a dewetting solderability issue is when the solder does initial "wet" and makes a metallurgical bond with the surface you are trying to solder but then puddles/retracts on that surface similar to an oil on water reaction.

The JSTD-002C, Figure 2B, page 43, has photos of dewetting and nonwetting - microsections, actually. A draft of the later revised standard is currently available:

Hope this helps.

RL

I was hoping to highlight the difference between perception and experience, in this one case. Subjectivity and objectivity can be slippery critters for some.

Best wishes in your future attempts at reading and comprehemsion.

RL

Which can ONLY happen WHILE making the solder joint, and it is NOT "de-wetting" if it is not still wet as the tip is pulled back, IT EVER WAS, and if it ever DOES get wetted, it NEVER loses it. So the entire goddamned premise is based on faulty observations of the process, as well as faulty decisions about what was actually happening with what the idiot was observing.

So, if the metallurgical "wetting" does occur, then your "dewetting" instance cannot occur, and if there is found to be an area that is not wetted, it did not "dewet", it NEVER was wetted.

Goddamned make it up as you go along twits that write texts does not mean that they are experts, nor does it mean that the crap they guessed at matches reality in any way.

So your quotations mean not a goddamned thing unless they came from someone with advanced degrees in metallurgy, which I am more than a little certain that no electronics soldering book authoring twit is.

Next time, you should try proofreading your horseshit before you spew it.

The retarded peanut gallery comments are what get dumbfucktards like you the retard moniker.

You do not need to be doing it, and you should at least get it right should you decide to go the retarded peanut gallery comment twit route.

Yes I know. It's called a cold solder joint.

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"> It is NOT magnetic!

Hmmm, and I thought ground loops were magnetic?

George H.

Now explain that to everyone else here that thinks there is such an animal.

Also, there probably hasn't been a cold joint made in a mfg process in well over 15 years. Cleam PCB mfg process and high performance fluxes, etc. have made the process pretty much trouble free for a very long time.

A person, however, that has little experience or knowledge, can make one in a heartbeat on hand soldered operations.

The main reason is that managers were notoriously too incompetent to actually discern between a good, experienced and knowledgeable solder tech, and someone that simply should not be doing the job.. All that, in the name of having an easy job. Managers that ONLY manage the paperwork are the worst kind in ANY technical or industrial setting. If they do not know what is going on at a very intimate level, they have no business in the position of management over those that do (or do not).

Did you ever take an electronics instructional course of ANY kind?

Or are you guessing as you go the whole way through life?

Do you even know what a recirculating current is?

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Sorry Bill, I didn't mean to pick on you. It just seemed like a silly statement.

I=E2=80=99ve dealt with plenty of ground loops. (most of my own making=E2= =80=A6 but how else do you learn if you don=E2=80=99t make mistakes?) All of them wer= e =E2=80=98bad=E2=80=99 because of magnetic pickup. (My favorite way to test= for ground loops is to bring in the 150W Weller soldering gun, pull the trigger and hold it near the circuit=E2=80=A6 It=E2=80=99s fun to wave it around..)

And no, I have no idea what a =E2=80=98recirculating=E2=80=99 current is? = Unless you=E2=80=99re speaking of inductors.

George H.

Have you never figured out why a device that is in a chassis, like your home stereo or such, only had one central ground stud location inside?

Sure, modern stereos are different than when they were in metal chassis, but there are still all kinds of rack mount devices and such out there, and you'll find that they have a single internal ground tie point.

I am talking about commercial and industrial products too, not just audio. That was just an example. Central tie points for "chassis ground" in a system is essential.

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Sure Bill, I think most of us here who are designing and building electronics know about using a star ground. The ground loop problem usually crops up when you want to connect one instrument to another.

But your statement was "it is NOT magnetic, it is a ground loop". I claim that ground loops are only a problem because of magnetic fields. Perhaps you don't agree with this?

Hmmm (just thinking) If you do a poor job of laying out your ground you can have IR voltage drops along the ground lines that can screw up the low level signals...(I've been biten by that bug too.) But that's far from the topic of 60 Hz Hum.

George H.

That is why the ground for the chassis / power supply, and what is typically referred to as "signal ground" are separated in certain PCB layouts / circuit segment layouts.