Lead-free. The great time waster ...

[Arfa Daily]

Teac amplifier. Tap almost anywhere on the main board, and the left channel
would crackle a bit and the power level would drop. Sometimes, the channel
would disappear altogether. Sometimes that was without provocation.
Sometimes only with provocation. Sometimes, it would come back on its own.
Sometimes it wouldn't. Flexing the pcb wouldn't make it do it. Poking every
single component wouldn't either. Neither would they make it come back if it
was in one of its 'off' moods ...

Second time in for the same problem. Had many joints resoldered last time,
and seemed ok, but back within a day of the owner getting it home.

This time, I finished up reflowing every joint in an area about 6" square,
so a lot of joints. I did it with a headband magnifier on as well as my
glasses. Other than being lead-free 'bad' looking, not a single one of the
joints appeared to be poor. And yet, it cured the problem, so one of them
was.

So that was the better part of another hour wasted on it, and I got to
wondering just how much time world-wide, this crap lead-free substitute
soldering technology, has caused to be wasted. And how much wasted fuel etc
with owners having to return items like this one, that are still faulty. And
how much stuff has been consigned to the junk pile, either because the bad
joint couldn't be found within the time constraints of the value of the
equipment, or because of multiple returns and the owner or the repair shop
just giving up on it ?

It really never has been thought through any more than to a "seems like a
good idea" level, has it ?

Arfa

 

[N_Cook]

On 07/08/2013 16:05, Arfa Daily wrote:

Teac amplifier. Tap almost anywhere on the main board, and the left
channel would crackle a bit and the power level would drop. Sometimes,
the channel would disappear altogether. Sometimes that was without
provocation. Sometimes only with provocation. Sometimes, it would come
back on its own. Sometimes it wouldn't. Flexing the pcb wouldn't make it
do it. Poking every single component wouldn't either. Neither would they
make it come back if it was in one of its 'off' moods ...

Second time in for the same problem. Had many joints resoldered last
time, and seemed ok, but back within a day of the owner getting it home.

This time, I finished up reflowing every joint in an area about 6"
square, so a lot of joints. I did it with a headband magnifier on as
well as my glasses. Other than being lead-free 'bad' looking, not a
single one of the joints appeared to be poor. And yet, it cured the
problem, so one of them was.

So that was the better part of another hour wasted on it, and I got to
wondering just how much time world-wide, this crap lead-free substitute
soldering technology, has caused to be wasted. And how much wasted fuel
etc with owners having to return items like this one, that are still
faulty. And how much stuff has been consigned to the junk pile, either
because the bad joint couldn't be found within the time constraints of
the value of the equipment, or because of multiple returns and the owner
or the repair shop just giving up on it ?

It really never has been thought through any more than to a "seems like
a good idea" level, has it ?

Arfa

If I know or suspect I have PbF in there, the first mechanical exerciser
I use is a feather. Use the normal plastic pen barrel and you are
likely to "repair" the joint until the next time vibration or thermal
movement opens it up again

 

[N_Cook]

On 07/08/2013 17:31, Robert Macy wrote:

On Wednesday, August 7, 2013 8:05:11 AM UTC-7, Arfa Daily wrote:
Teac amplifier. Tap almost anywhere on the main board, and the left channel would crackle a bit and the power level would drop. Sometimes, the channel would disappear altogether. Sometimes that was without provocation. Sometimes only with provocation. Sometimes, it would come back on its own. Sometimes it wouldn't. Flexing the pcb wouldn't make it do it. Poking every single component wouldn't either. Neither would they make it come back if it was in one of its 'off' moods ... Second time in for the same problem. Had many joints resoldered last time, and seemed ok, but back within a day of the owner getting it home. This time, I finished up reflowing every joint in an area about 6" square, so a lot of joints. I did it with a headband magnifier on as well as my glasses. Other than being lead-free 'bad' looking, not a single one of the joints appeared to be poor. And yet, it cured the problem, so one of them was. So that was the better part of another hour wasted on it, and I got to
wondering just how much time world-wide, this crap lead-free substitute soldering technology, has caused to be wasted. And how much wasted fuel etc with owners having to return items like this one, that are still faulty. And how much stuff has been consigned to the junk pile, either because the bad joint couldn't be found within the time constraints of the value of the equipment, or because of multiple returns and the owner or the repair shop just giving up on it ? It really never has been thought through any more than to a "seems like a good idea" level, has it ? Arfa

don't you like the way google quotes?

it's my understanding that the military does NOT accept lead-free solder due to a reliability issue.

Also, there have beeen some pictures showing 'whiskers' growing off the gunk, VERY long, shorting type whiskers.

The military, aerospace, nuclear and medical electronics all have
derogation from the laws applying to PbF. Makes you wonder what the auto
industries do (no derogation for them) .
Anyone on this forum in automobile engine management/ABS etc electronics
(ie not ICE stuff)
?
For all else it is twisted green-thinking that means the refuse tips
fill up with more electronic junk

 

[Robert Macy]

On Wednesday, August 7, 2013 8:05:11 AM UTC-7, Arfa Daily wrote:

Teac amplifier. Tap almost anywhere on the main board, and the left channel would crackle a bit and the power level would drop. Sometimes, the channel would disappear altogether. Sometimes that was without provocation. Sometimes only with provocation. Sometimes, it would come back on its own. Sometimes it wouldn't. Flexing the pcb wouldn't make it do it. Poking every single component wouldn't either. Neither would they make it come back if it was in one of its 'off' moods ... Second time in for the same problem. Had many joints resoldered last time, and seemed ok, but back within a day of the owner getting it home. This time, I finished up reflowing every joint in an area about 6" square, so a lot of joints. I did it with a headband magnifier on as well as my glasses. Other than being lead-free 'bad' looking, not a single one of the joints appeared to be poor. And yet, it cured the problem, so one of them was. So that was the better part of another hour wasted on it, and I got to wondering just how much time world-wide, this crap lead-free substitute soldering technology, has caused to be wasted. And how much wasted fuel etc with owners having to return items like this one, that are still faulty. And how much stuff has been consigned to the junk pile, either because the bad joint couldn't be found within the time constraints of the value of the equipment, or because of multiple returns and the owner or the repair shop just giving up on it ? It really never has been thought through any more than to a "seems like a good idea" level, has it ? Arfa

don't you like the way google quotes?

it's my understanding that the military does NOT accept lead-free solder due to a reliability issue.

Also, there have beeen some pictures showing 'whiskers' growing off the gunk, VERY long, shorting type whiskers.

 

[Jeff Liebermann]

On Wed, 7 Aug 2013 16:05:11 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com> wrote:

This time, I finished up reflowing every joint in an area about 6" square,
so a lot of joints.

I had to do the same thing with an LCD monitor PCB. However, I got
lazy and tried an experiment. I smeared the area in question with
some flux. Instead of tediously resoldering each connection by hand,
I used a hot air SMT desoldering station, giving the area in question
a good blast of solder melting hot air. Afterwards, some touchup with
the soldering iron consisting mostly of small balls of solder between
the pads.

The flux produced the usual disgusting mess and associated smoke
signals, but the underlying solder connections were gorgeous and far
better than I could have done with a soldering iron. Some illegal
trichloroethylene solvent cleaned up the flux mess. Elapsed time
(ignoring an interruption) was about 10 minutes. With a soldering
iron, I would guess maybe 30-45 minutes.


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Jeff Liebermann]

On Wed, 7 Aug 2013 09:31:07 -0700 (PDT), Robert Macy
<robert.a.macy@gmail.com> wrote:

Also, there have beeen some pictures showing 'whiskers' growing off the gunk, VERY long, shorting type whiskers.

Tin Whiskers. Note that zinc will do the same thing, but to a much
lesser degree:
<http://nepp.nasa.gov/whisker/>
Photos:
<http://nepp.nasa.gov/whisker/photos/index.html>


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Arfa Daily]

"N_Cook" <diverse@tcp.co.uk> wrote in message
news:ktttfr$fjc$1@dont-email.me...

On 07/08/2013 17:31, Robert Macy wrote:
On Wednesday, August 7, 2013 8:05:11 AM UTC-7, Arfa Daily wrote:
Teac amplifier. Tap almost anywhere on the main board, and the left
channel would crackle a bit and the power level would drop. Sometimes,
the channel would disappear altogether. Sometimes that was without
provocation. Sometimes only with provocation. Sometimes, it would come
back on its own. Sometimes it wouldn't. Flexing the pcb wouldn't make it
do it. Poking every single component wouldn't either. Neither would they
make it come back if it was in one of its 'off' moods ... Second time in
for the same problem. Had many joints resoldered last time, and seemed
ok, but back within a day of the owner getting it home. This time, I
finished up reflowing every joint in an area about 6" square, so a lot
of joints. I did it with a headband magnifier on as well as my glasses.
Other than being lead-free 'bad' looking, not a single one of the joints
appeared to be poor. And yet, it cured the problem, so one of them was.
So that was the better part of another hour wasted on it, and I got to
wondering just how much time world-wide, this crap lead-free substitute
soldering technology, has caused to be wasted. And how much wasted fuel
etc with owners having to return items like this one, that are still
faulty. And how much stuff has been consigned to the junk pile, either
because the bad joint couldn't be found within the time constraints of the
value of the equipment, or because of multiple returns and the owner or
the repair shop just giving up on it ? It really never has been thought
through any more than to a "seems like a good idea" level, has it ? Arfa

don't you like the way google quotes?

it's my understanding that the military does NOT accept lead-free solder
due to a reliability issue.

Also, there have beeen some pictures showing 'whiskers' growing off the
gunk, VERY long, shorting type whiskers.


The military, aerospace, nuclear and medical electronics all have
derogation from the laws applying to PbF. Makes you wonder what the auto
industries do (no derogation for them) .
Anyone on this forum in automobile engine management/ABS etc electronics
(ie not ICE stuff)
?
For all else it is twisted green-thinking that means the refuse tips fill
up with more electronic junk

Friend of mine repairs a few for a local car repair outfit, and he tells me
that it's mostly bad joints.

BTW, what does "don't you like the way google quotes ?" mean, anyone ... ?

Arfa

 

[Arfa Daily]

"Jeff Liebermann" <jeffl@cruzio.com> wrote in message
news:s1g509tk90v3lga2apdlcnn7samhf1tq3k@4ax.com...

On Wed, 7 Aug 2013 16:05:11 +0100, "Arfa Daily"
arfa.daily@ntlworld.com> wrote:

This time, I finished up reflowing every joint in an area about 6" square,
so a lot of joints.

I had to do the same thing with an LCD monitor PCB. However, I got
lazy and tried an experiment. I smeared the area in question with
some flux. Instead of tediously resoldering each connection by hand,
I used a hot air SMT desoldering station, giving the area in question
a good blast of solder melting hot air. Afterwards, some touchup with
the soldering iron consisting mostly of small balls of solder between
the pads.

The flux produced the usual disgusting mess and associated smoke
signals, but the underlying solder connections were gorgeous and far
better than I could have done with a soldering iron. Some illegal
trichloroethylene solvent cleaned up the flux mess. Elapsed time
(ignoring an interruption) was about 10 minutes. With a soldering
iron, I would guess maybe 30-45 minutes.


--
Jeff Liebermann

I've never thought to do it like that. I guess you would have to be pretty
careful that components did not finish up falling out of the board, if both
ends were melted at the same time ...

An hour after this amp, I had a W-Audio powered speaker on the bench. It
hissed and spat like a demented snake. You would have sworn that it was a
noisy opamp, or maybe a noisy resistor around an opamp, but no, it was
another invisible and un-provokable lead free joint, again requiring a
blanket re-solder of a whole sub-board in the preamp section to get a fix.

Arfa

 

[Jeff Liebermann]

On Thu, 8 Aug 2013 02:04:38 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com> wrote:

I've never thought to do it like that. I guess you would have to be pretty
careful that components did not finish up falling out of the board, if both
ends were melted at the same time ...

I did have some small parts fall out. I always take photos so that I
can re-assemble the unit. It was easy to replace parts. I could not
have done it by suspending the PCB component side up, and reflowing
the solder from the bottom. That results in lots of solder drip,
which would later need to be resoldered by hand.

An hour after this amp, I had a W-Audio powered speaker on the bench. It
hissed and spat like a demented snake. You would have sworn that it was a
noisy opamp, or maybe a noisy resistor around an opamp, but no, it was
another invisible and un-provokable lead free joint, again requiring a
blanket re-solder of a whole sub-board in the preamp section to get a fix.

Well, I had a Viewsonic (something) monitor last week that was
comatose. Push the power button and nothing happened. I got lucky
and found the exact same problem on YouTube. An RoHS solder
connection to a 3 terminal regulator like to crack after a few years,
causing an intermittent open circuit. That would be easy to find and
fix, except that it also blows up the regulator IC. I replaced the IC
and resoldered the regulator, and it works. Since no other parts
exhibited the same problem, my guess(tm) is that since the 3 terminal
regulator is attached to a heat sink, the connection was too cold
during wave soldering to make a decent connection.

On computahs, the only parts I find with cracked solder connections
are physically big and heavy parts, that play heat sink during
soldering. Also, components that vibrate, such as switching
transformers and coils, which crack the solder joint with ultrasonics.



--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[Phil Allison]

"Arfa Daily"

Teac amplifier. Tap almost anywhere on the main board, and the left
channel would crackle a bit and the power level would drop. Sometimes, the
channel would disappear altogether. Sometimes that was without
provocation. Sometimes only with provocation. Sometimes, it would come
back on its own. Sometimes it wouldn't. Flexing the pcb wouldn't make it
do it. Poking every single component wouldn't either. Neither would they
make it come back if it was in one of its 'off' moods ...

Second time in for the same problem. Had many joints resoldered last time,
and seemed ok, but back within a day of the owner getting it home.

This time, I finished up reflowing every joint in an area about 6" square,
so a lot of joints. I did it with a headband magnifier on as well as my
glasses. Other than being lead-free 'bad' looking, not a single one of the
joints appeared to be poor. And yet, it cured the problem, so one of them
was.

So that was the better part of another hour wasted on it, and I got to
wondering just how much time world-wide, this crap lead-free substitute
soldering technology, has caused to be wasted. And how much wasted fuel
etc with owners having to return items like this one, that are still
faulty. And how much stuff has been consigned to the junk pile, either
because the bad joint couldn't be found within the time constraints of the
value of the equipment, or because of multiple returns and the owner or
the repair shop just giving up on it ?

It really never has been thought through any more than to a "seems like a
good idea" level, has it ?

** Sure enough, Pb free solder does not "wet" as nicely as regular Pb/Sn
solder - but that is no the only thing that produces dry joints.

1. All the component leads must be clean and bright and there must be no
defective tin plating on any.

2. The use of water soluble fluxes makes the above critical as they have
little ability to remove oxides.

Plus Chinese manufacture is often carried out by inexperienced workers,
acting in haste and under great pressure - which leads to imperfect results.



.... Phil

 

[N_Cook]

On 07/08/2013 22:54, Jeff Liebermann wrote:

On Wed, 7 Aug 2013 16:05:11 +0100, "Arfa Daily"
arfa.daily@ntlworld.com> wrote:

This time, I finished up reflowing every joint in an area about 6" square,
so a lot of joints.

I had to do the same thing with an LCD monitor PCB. However, I got
lazy and tried an experiment. I smeared the area in question with
some flux. Instead of tediously resoldering each connection by hand,
I used a hot air SMT desoldering station, giving the area in question
a good blast of solder melting hot air. Afterwards, some touchup with
the soldering iron consisting mostly of small balls of solder between
the pads.

The flux produced the usual disgusting mess and associated smoke
signals, but the underlying solder connections were gorgeous and far
better than I could have done with a soldering iron. Some illegal
trichloroethylene solvent cleaned up the flux mess. Elapsed time
(ignoring an interruption) was about 10 minutes. With a soldering
iron, I would guess maybe 30-45 minutes.

I'll try that next time. I've half the time , when divining the PbF
fault by individual tugging on component leads with long-nose pliers,
discovered the faulty "component" was the most minor of components, wire
links. Presumably there is no manufacturing processing gripping the wire
to add resistors or whatever,just corner bends,so not leaving
microscopic deformations that will then mechanically catch the solder

 

[N_Cook]

On 08/08/2013 01:57, Arfa Daily wrote:

"N_Cook" <diverse@tcp.co.uk> wrote in message
news:ktttfr$fjc$1@dont-email.me...
On 07/08/2013 17:31, Robert Macy wrote:
On Wednesday, August 7, 2013 8:05:11 AM UTC-7, Arfa Daily wrote:
Teac amplifier. Tap almost anywhere on the main board, and the left
channel would crackle a bit and the power level would drop.
Sometimes, the channel would disappear altogether. Sometimes that
was without provocation. Sometimes only with provocation. Sometimes,
it would come back on its own. Sometimes it wouldn't. Flexing the
pcb wouldn't make it do it. Poking every single component wouldn't
either. Neither would they make it come back if it was in one of its
'off' moods ... Second time in for the same problem. Had many joints
resoldered last time, and seemed ok, but back within a day of the
owner getting it home. This time, I finished up reflowing every
joint in an area about 6" square, so a lot of joints. I did it with
a headband magnifier on as well as my glasses. Other than being
lead-free 'bad' looking, not a single one of the joints appeared to
be poor. And yet, it cured the problem, so one of them was. So that
was the better part of another hour wasted on it, and I got to
wondering just how much time world-wide, this crap lead-free
substitute soldering technology, has caused to be wasted. And how much
wasted fuel etc with owners having to return items like this one, that
are still faulty. And how much stuff has been consigned to the junk
pile, either because the bad joint couldn't be found within the time
constraints of the value of the equipment, or because of multiple
returns and the owner or the repair shop just giving up on it ? It
really never has been thought through any more than to a "seems like a
good idea" level, has it ? Arfa

don't you like the way google quotes?

it's my understanding that the military does NOT accept lead-free
solder due to a reliability issue.

Also, there have beeen some pictures showing 'whiskers' growing off
the gunk, VERY long, shorting type whiskers.


The military, aerospace, nuclear and medical electronics all have
derogation from the laws applying to PbF. Makes you wonder what the
auto industries do (no derogation for them) .
Anyone on this forum in automobile engine management/ABS etc
electronics (ie not ICE stuff)
?
For all else it is twisted green-thinking that means the refuse tips
fill up with more electronic junk


Friend of mine repairs a few for a local car repair outfit, and he tells
me that it's mostly bad joints.

BTW, what does "don't you like the way google quotes ?" mean, anyone ... ?

Arfa

Does simple SnPb admixture test indicate the solder used is likely to be
PbF (goes crazed) or leaded solder (stays shiney) ?

 

[Arfa Daily]

"N_Cook" <diverse@tcp.co.uk> wrote in message
news:ktvkfh$joe$1@dont-email.me...

On 08/08/2013 01:57, Arfa Daily wrote:


"N_Cook" <diverse@tcp.co.uk> wrote in message
news:ktttfr$fjc$1@dont-email.me...
On 07/08/2013 17:31, Robert Macy wrote:
On Wednesday, August 7, 2013 8:05:11 AM UTC-7, Arfa Daily wrote:
Teac amplifier. Tap almost anywhere on the main board, and the left
channel would crackle a bit and the power level would drop.
Sometimes, the channel would disappear altogether. Sometimes that
was without provocation. Sometimes only with provocation. Sometimes,
it would come back on its own. Sometimes it wouldn't. Flexing the
pcb wouldn't make it do it. Poking every single component wouldn't
either. Neither would they make it come back if it was in one of its
'off' moods ... Second time in for the same problem. Had many joints
resoldered last time, and seemed ok, but back within a day of the
owner getting it home. This time, I finished up reflowing every
joint in an area about 6" square, so a lot of joints. I did it with
a headband magnifier on as well as my glasses. Other than being
lead-free 'bad' looking, not a single one of the joints appeared to
be poor. And yet, it cured the problem, so one of them was. So that
was the better part of another hour wasted on it, and I got to
wondering just how much time world-wide, this crap lead-free
substitute soldering technology, has caused to be wasted. And how much
wasted fuel etc with owners having to return items like this one, that
are still faulty. And how much stuff has been consigned to the junk
pile, either because the bad joint couldn't be found within the time
constraints of the value of the equipment, or because of multiple
returns and the owner or the repair shop just giving up on it ? It
really never has been thought through any more than to a "seems like a
good idea" level, has it ? Arfa

don't you like the way google quotes?

it's my understanding that the military does NOT accept lead-free
solder due to a reliability issue.

Also, there have beeen some pictures showing 'whiskers' growing off
the gunk, VERY long, shorting type whiskers.


The military, aerospace, nuclear and medical electronics all have
derogation from the laws applying to PbF. Makes you wonder what the
auto industries do (no derogation for them) .
Anyone on this forum in automobile engine management/ABS etc
electronics (ie not ICE stuff)
?
For all else it is twisted green-thinking that means the refuse tips
fill up with more electronic junk


Friend of mine repairs a few for a local car repair outfit, and he tells
me that it's mostly bad joints.

BTW, what does "don't you like the way google quotes ?" mean, anyone ...
?

Arfa

Does simple SnPb admixture test indicate the solder used is likely to be
PbF (goes crazed) or leaded solder (stays shiney) ?

Don't know is the simple answer. I shall see him tomorrow. I'll ask if I
remember.

Arfa

 

[Arfa Daily]

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:b6gni5Ftjp7U1@mid.individual.net...

"Arfa Daily"

Teac amplifier. Tap almost anywhere on the main board, and the left
channel would crackle a bit and the power level would drop. Sometimes,
the channel would disappear altogether. Sometimes that was without
provocation. Sometimes only with provocation. Sometimes, it would come
back on its own. Sometimes it wouldn't. Flexing the pcb wouldn't make it
do it. Poking every single component wouldn't either. Neither would they
make it come back if it was in one of its 'off' moods ...

Second time in for the same problem. Had many joints resoldered last
time, and seemed ok, but back within a day of the owner getting it home.

This time, I finished up reflowing every joint in an area about 6"
square, so a lot of joints. I did it with a headband magnifier on as well
as my glasses. Other than being lead-free 'bad' looking, not a single one
of the joints appeared to be poor. And yet, it cured the problem, so one
of them was.

So that was the better part of another hour wasted on it, and I got to
wondering just how much time world-wide, this crap lead-free substitute
soldering technology, has caused to be wasted. And how much wasted fuel
etc with owners having to return items like this one, that are still
faulty. And how much stuff has been consigned to the junk pile, either
because the bad joint couldn't be found within the time constraints of
the value of the equipment, or because of multiple returns and the owner
or the repair shop just giving up on it ?

It really never has been thought through any more than to a "seems like a
good idea" level, has it ?


** Sure enough, Pb free solder does not "wet" as nicely as regular Pb/Sn
solder - but that is no the only thing that produces dry joints.

1. All the component leads must be clean and bright and there must be no
defective tin plating on any.

2. The use of water soluble fluxes makes the above critical as they have
little ability to remove oxides.

Plus Chinese manufacture is often carried out by inexperienced workers,
acting in haste and under great pressure - which leads to imperfect
results.



... Phil

Agreed that lead-free is not the only thing that produces bad joints Phil,
but I think you would have to agree that it is considerably less forgiving
of poor soldering practices than leaded solder ever was. Having been at the
sharp end of the repair business since PCBs were in their infancy, I would
have said that about 10 years ago, the technology was mature and at a level
peak of performance. Bad joints were comparatively rare, and when a board
did have them, they were in expected places like power devices and
connectors. Further, they were easy and cheap, time-wise, to repair. Most
were easily find-able with either the Mk I eyeball, the Mk I Biro pen, the
butt end of the Mk I screwdriver, or a can of freezer.

Now, in lead-free, they often defy any of those methods to find them, and
the only sensible course of action to get a fix in a practical time, is to
do blanket reworks of suspected areas.

Since the introduction of lead-free soldering technology, the reliability of
production-soldered boards has gone down substantially, and it is no longer
what I would consider to be a mature and reliable technology, as it was in
the not-too-distant past.

Arfa

 

[N_Cook]

On 08/08/2013 09:48, Arfa Daily wrote:

"Phil Allison" <phil_a@tpg.com.au> wrote in message
news:b6gni5Ftjp7U1@mid.individual.net...

Agreed that lead-free is not the only thing that produces bad joints
Phil, but I think you would have to agree that it is considerably less
forgiving of poor soldering practices than leaded solder ever was.
Having been at the sharp end of the repair business since PCBs were in
their infancy, I would have said that about 10 years ago, the technology
was mature and at a level peak of performance. Bad joints were
comparatively rare, and when a board did have them, they were in
expected places like power devices and connectors. Further, they were
easy and cheap, time-wise, to repair. Most were easily find-able with
either the Mk I eyeball, the Mk I Biro pen, the butt end of the Mk I
screwdriver, or a can of freezer.

Now, in lead-free, they often defy any of those methods to find them,
and the only sensible course of action to get a fix in a practical time,
is to do blanket reworks of suspected areas.

Since the introduction of lead-free soldering technology, the
reliability of production-soldered boards has gone down substantially,
and it is no longer what I would consider to be a mature and reliable
technology, as it was in the not-too-distant past.

Arfa

The big guns tester that I've found a couple of PbF failings with. An
engraver tool with a "sharpened" and de-headed nylon bolt fitted in the
active end. You need to feed any sound monitoring into headphones as the
engraver noise is terrible, only apply to the pcb not any components .

 

[Jeff Liebermann]

On Thu, 08 Aug 2013 09:22:13 +0100, N_Cook <diverse@tcp.co.uk> wrote:

Does simple SnPb admixture test indicate the solder used is likely to be
PbF (goes crazed) or leaded solder (stays shiney) ?

I have the reverse problem identifying the solder on older boards made
during the transition. I just add some lead-tin solder. If it turns
dull, the board uses unleaded solder. If it stays shiny, the board
used lead-tin. I don't really care which was used as I tend to use
lead-tin for all my repairs, after sucking up as much of the lead-free
solder from the affected connection. That's good for a few
components, but useless for PCB's full of hidden intermittents.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558