Changed display connector to no avail.
I resoldered all the tiny resistors near the display connector and anything else that looked suspicious. Success!

Looks like no lead solder causing a weak connection. I bet there will be others down the road.

The interface to the SMA connectors is not very rugged and the SMA
connectors themselves are not rugged so be gentle, use connector savers or
keep the supplied short cables connected. A true rugged device for this
frequency range would use N connectors.

On Mon, Apr 17, 2023 at 11:29 AM Edward Prest <prest.edward.3@gmail.com>
wrote:

> Changed display connector to no avail.
> I resoldered all the tiny resistors near the display connector and
> anything else that looked suspicious. Success!
>
> Looks like no lead solder causing a weak connection. I bet there will be
> others down the road.
>
>
>

GOTCHA

now you know why i hate that new lead free stuff

does not work as good in my view as the old lead tin mixture we all
still use in our hobby (at least i do still use it ... others??)

dg9bfc sigi

Am 17.04.2023 um 17:19 schrieb Edward Prest:

> Changed display connector to no avail.
> I resoldered all the tiny resistors near the display connector and
> anything else that looked suspicious. Success!
>
> Looks like no lead solder causing a weak connection. I bet there will
> be others down the road.
>

Lead-free causes more problems than not.



In real world engineering, it is better to avoid soldering altogether or if not, the repairability is expensive.



The logic about not using lead is simply ridiculous in the hands of professionals.



And my kids do not eat solder.



W4JDY

Most large electronics companies have test data to show lead free is inferior to tin/lead solder not only in the strength of the solder joint as well as the higher temperature soldering profiles needed to get a "good" solder joint are extremely hard to control. No surprise at all that we are seeing many soldering intermittent connection issues with lead free.

This Ham will only use tin/lead solder and I buy only 60/40 when I find it. But buyer be aware, there is also a ton of really poor quality solder coming out of China. Just like our NanoVNA's need to find a quality source and expect to pay more. Actually much more.

On 4/17/23 8:44 PM, W4JDY wrote:
> Lead-free causes more problems than not.
>
> In real world engineering, it is better to avoid soldering altogether or
> if not, the repairability is expensive.
>
> The logic about not using lead is simply ridiculous in the hands of
> professionals.
>
> And my kids do not eat solder.
>
> W4JDY

The problem isn't eating it or being exposed to lead fumes on a bench
while hand soldering every couple of weeks. Or even lead fumes near a
production line doing reflow or wave soldering. The fume problem is
fixed by proper ventilation, too - all the benches at work have little
extractor fan units, along with the anti-ESD ionizers.

The reason for RoHS is the lead leaching out or winding up in smoke from
"recycling" of millions of tons of discarded electronics, and that
affects everyone. Particularly those who are unfortunate enough to live
near such a site - The Exide Battery Plant in Los Angeles is a nice
example, as well as anyone who lives near a major highway.


In real world mass production, RoHS and lead free solder is a "solved
problem" - Millions of electronic devices are manufactured without lead
and keep on working, in all manner of environments.

You do need different tools and techniques. You don't have that nice
"plastic" phase where the solder hasn't quite cooled. Yeah, eutectic
Lead/Tin is a nice medium with which to work.

SMT devices are a pain to repair/replace regardless. And I will readily
agree that "repairability" is pretty much at the bottom of the list for
most modern electronics.

People did make the same complaints about repairability when we went
from point to point wiring to PCBs, though. And all those instructions
in,e.g. Boys First Book of Electronics, about heating up your soldering
copper on the stove are positively quaint now.

On 4/18/23 6:32 AM, Mark Libner wrote:
> Most large electronics companies have test data to show lead free is
> inferior to tin/lead solder not only in the strength of the solder joint
> as well as the higher temperature soldering profiles needed to get a
> "good" solder joint are extremely hard to control. No surprise at all
> that we are seeing many soldering intermittent connection issues with
> lead free.

Can you point to a published example of such test data that says
lead-free is inferior in the last 10 years.

There's plenty of published data from a variety of manufacturers that
says that you can get reliable results. I don't think "extremely hard
to control" is an accurate statement. Anyone doing production work is
going to have good enough temperature and time control on their fab
line. Yeah, you can't just load your wave solder machine up with RoHS
solder instead of tin/lead eutectic and run the same profile. In the
2000s, sure, plenty of yield issues. But now, I don't think so.

And yes, there are older designs and techniques which depended on the
mechanical properties of the solder. Although I was always taught
"solder is not structural", as I built circuits that were essentially 3D
artwork with solder holding it together. But that's not "product
production".

In space hardware, tin/lead is still used, but that's because there's 50
years of established procedures and test results, and nobody wants to
pay to do testing to change that for other materials for a very small
volume market. There's already all sorts of peculiarities in space.


>
> This Ham will only use tin/lead solder and I buy only 60/40 when I find
> it. But buyer be aware, there is also a ton of really poor quality
> solder coming out of China. Just like our NanoVNA's need to find a
> quality source and expect to pay more. Actually much more.


That might be more a function of not-so-wonderful manufacturing
processes than the materials being used.

i do not even have kids :-)

and i also do not chew on solder wire or lick on the tip of the iron (outch)

dg9bfc sigi


Am 18.04.2023 um 05:44 schrieb W4JDY:

>
> Lead-free causes more problems than not.
>
> In real world engineering, it is better to avoid soldering altogether
> or if not, the repairability is expensive.
>
> The logic about not using lead is simply ridiculous in the hands of
> professionals.
>
> And my kids do not eat solder.
>
> W4JDY
>
> *From:* NanoVNAV2@groups.io <NanoVNAV2@groups.io> *On Behalf Of
> *Siegfried Jackstien
> *Sent:* Monday, April 17, 2023 3:46 PM
> *To:* NanoVNAV2@groups.io
> *Subject:* Re: [nanovnav2] I dropped my VNA v2plus4 now Fixed
>
> GOTCHA
>
> now you know why i hate that new lead free stuff
>
> does not work as good in my view as the old lead tin mixture we all
> still use in our hobby (at least i do still use it ... others??)
>
> dg9bfc sigi
>
> Am 17.04.2023 um 17:19 schrieb Edward Prest:
>
> Changed display connector to no avail.
> I resoldered all the tiny resistors near the display connector and
> anything else that looked suspicious. Success!
>
> Looks like no lead solder causing a weak connection. I bet there
> will be others down the road.
>
>
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>
> Virus-free.www.avast.com
> <https://www.avast.com/sig-email?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=emailclient>
>
>
> <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>

How about 63/37? It has the lowest soldering point. Hamfests are the
best place, I've found, to pick up the 'good stuff'. Our Gestapo
government will eventually eliminate all the good stuff via unelected
bureaucrats like the EPA.

Mike C. Sand Mtn GA


On 4/18/2023 9:32 AM, Mark Libner wrote:

> Most large electronics companies have test data to show lead free is
> inferior to tin/lead solder not only in the strength of the solder
> joint as well as the higher temperature soldering profiles needed to
> get a "good" solder joint are extremely hard to control. No surprise
> at all that we are seeing many soldering intermittent connection
> issues with lead free.
>
> This Ham will only use tin/lead solder and I buy only 60/40 when I
> find it. But buyer be aware, there is also a ton of really poor
> quality solder coming out of China. Just like our NanoVNA's need to
> find a quality source and expect to pay more. Actually much more.
>

The fumes from hand soldering are flux vapors; typically, from the rosin
core found in tin/lead solder. Soldering temperatures are nowhere near
high enough to vaporize metals (the boiling point of lead is 3,180 deg F).
You certainly don’t want to breathe flux fumes as they can cause irritation
and lead to asthma with prolonged exposure. It’s possible that some lead
oxide dust particles can be produced during soldering and be carried up by
the fumes. They should soon settle around the work surface due to weight.

Tin/Lead solder is allowed for repair and rework, but not on anything
intended for sale. It’s best to first remove any lead-free solder from a
joint before applying new lead solder during a repair.

Use some basic precautions:

· Solder in a well-ventilated area, use a fan if possible.

· Don’t eat, drink, or smoke while soldering (don’t smoke ever!).

· Wash your hands soon after soldering or handling solder.

· Don’t eat until your hands are washed.

· Clean the work surface area after soldering.

On Mon, Apr 17, 2023 at 11:29 AM Edward Prest <prest.edward.3@gmail.com>
wrote:

> Changed display connector to no avail.
> I resoldered all the tiny resistors near the display connector and
> anything else that looked suspicious. Success!
>
> Looks like no lead solder causing a weak connection. I bet there will be
> others down the road.
>
>
>

I would love to point to published reports however I don't know of a single company that wants to get into the legal battle of publishing data and then stay compliant with the laws. I can hear the lawyers now, you had data to show something was better and you built an inferior product just because of the law. Yes, that is exactly the issue and a fact of the world we live in.

In the early 2000s there were many reports published. But then came the lawyers and tight controls on what was published. And as for the control of soldering profiles in manufacturing, if you can even get the data, soldering rework and scrap rates tell that story. But again, not something any company publishes.

I spent 43 years in the field of electronics reliability and oversaw millions of hours of environmental testing that clearly shows the softer more compliant tin lead solder is superior to lead free. It is all part of the TC matching of electronic components and the PC boards. But I also know we must protect our environment so the entire lead free initiative came down to finding a workable solution that survived well enough that the general public would accept.

It is a trade off plain and simple. But starting at about 250 thermal shocks -40C to +85C, a normal accelerated life test for electronic devices, lead free solder develops cracks - intermittent connections - that are not seen in over 1000 cycles in tin lead.

So for sure many companies are continuing to work to find ways to eliminate solder all together. And this is the best approach overall but so far more expensive.

I have said enough. The real issue is we will live with what we have and yes for the better good, enjoying a healthier planet.

On 4/19/23 5:33 AM, Bob W0EG wrote:
> The fumes from hand soldering are flux vapors; typically, from the rosin
> core found in tin/lead solder. Soldering temperatures are nowhere near
> high enough to vaporize metals (the boiling point of lead is 3,180 deg
> F).

You're exposed to vapors at temperatures below boiling - consider water
vapor - there's a significant concentration of water in the air I'm
immersed in, although the temperature is about 21C, well below 100C BP.

You don't have to be at the boiling point to have hazardous
concentrations of vapor - consider mercury - boils at 600+F, but at room
temperature the vapor pressure is high enough to be hazardous (0.01
torr, I think, so 10 ppm compared to 760 torr atmospheric pressure),
just being in the same room. (the classic problem is spilled mercury,
little droplets get into cracks in the floor, and evaporate forever)


Lead isn't as bad, but it's still significant, mostly because lead, like
mercury, is an accumulating toxin. The lead vapor concentration may be
down in the sub ppm range but it bioaccumulates. There's also an issue
with lead oxides - hot lead forms lead oxides in combination with air,
and those can be ingested as well. Over time, the lead concentration
builds up.

Flux smoke/vapors are another good reason for ventilation - but you'd
have that regardless. And while rosin is tree sap, and probably
unhealthy when burned, new fluxes might be worse. (consider tinners
fluid used for copper pipe, it's basically hydrochloric acid, which
while not a persistent toxin, is sure an irritant).

There's also the lead particulate problem. Lead and solder are soft, so
when you touch it, some rubs off. That sponge you're cleaning the tip
on? When the hot tip boils the water, little particles of solder or
oxides come off, and some gets into the air.


I doubt it's a problem if you're soldering once a month. But if you're
sitting at a bench soldering all day, or operating a wave or reflow
soldering station, yeah, you'd be concerned.