Post mortem on an IEC connector

[Arfa Daily]

"Adrian Tuddenham" <adrian@poppyrecords.invalid.invalid> wrote in message
news:1j047vt.qyzfd7n14ndyN%adrian@poppyrecords.invalid.invalid...

Eeyore <rabbitsfriendsandrelations@hotmail.com> wrote:


The EU Commission should be strung by their necks from lamp-posts for
being a
bunch of technically ignorant twats. Why do they think lead was used in
solder
in the first place ? For fun ?

In the past I have many times agreed with your facts, but I have often
disagreed with your way of expressing them. On this occasion I am with
you all the way.

Let's hope the first aeroplane to crash because of lead-free solder has
only Brussels diplomats and anti-lead campaigners on board.

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

As far as I know, at this point in time, the avionics industry still has an
exemption from having to use the stuff. Now I wonder why that could be ... ?

Arfa

 

[Meat Plow]

On Fri, 22 May 2009 01:49:59 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com>wrote:

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4A15CF3A.99BE032B@hotmail.com...


whit3rd wrote:

On May 21, 2:59 am, "N_Cook" <dive...@tcp.co.uk> wrote:
Obviously I've come acros melting/burning, starting from bad connection
arcing , but not this amount of damage, so am requesting other
opinions.

Burning right thru the pcb for 1/2 inch around the L pin of the IEC,
melting
of the plastic of the IEC above the burning and even the linecord plug

Yep, ring crack around a power solder connection, generates lots of
heat.

Possible. A victim of lead-free soldering ?
http://en.wikipedia.org/wiki/Tin_pest

Note that pure tin solder degrades below 13C. Yes that's right. And turns
to dust.
Adding a little copper doesn't stop it but slows it some but not enough.

The EU Commission should be strung by their necks from lamp-posts for
being a
bunch of technically ignorant twats. Why do they think lead was used in
solder in
the first place ? For fun ?

Graham


Just what I've been saying since they first mandated the hateful stuff ...

Arfa

Glad I stockpiled enough 60/40 to last me a lifetime. I could probably
sell it on Ebay for an exuberant price one day

This Tin Pest stuff sounds like a serious problem though.

 

[Arfa Daily]

"Meat Plow" <meat@petitmorte.net> wrote in message
news:2r31kp.ifs.17.5@news.alt.net...

On Fri, 22 May 2009 01:49:59 +0100, "Arfa Daily"
arfa.daily@ntlworld.com>wrote:


"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4A15CF3A.99BE032B@hotmail.com...


whit3rd wrote:

On May 21, 2:59 am, "N_Cook" <dive...@tcp.co.uk> wrote:
Obviously I've come acros melting/burning, starting from bad
connection
arcing , but not this amount of damage, so am requesting other
opinions.

Burning right thru the pcb for 1/2 inch around the L pin of the IEC,
melting
of the plastic of the IEC above the burning and even the linecord
plug

Yep, ring crack around a power solder connection, generates lots of
heat.

Possible. A victim of lead-free soldering ?
http://en.wikipedia.org/wiki/Tin_pest

Note that pure tin solder degrades below 13C. Yes that's right. And
turns
to dust.
Adding a little copper doesn't stop it but slows it some but not enough.

The EU Commission should be strung by their necks from lamp-posts for
being a
bunch of technically ignorant twats. Why do they think lead was used in
solder in
the first place ? For fun ?

Graham


Just what I've been saying since they first mandated the hateful stuff ...

Arfa


Glad I stockpiled enough 60/40 to last me a lifetime. I could probably
sell it on Ebay for an exuberant price one day

This Tin Pest stuff sounds like a serious problem though.

60/40 is still readily available here in pretty much all of the varieties
that it always was - I got a new roll just a couple of weeks ago. What was
interesting though, is that they have jacked up the price to match - almost
exactly - the cost of the dreaded lead-free, which up until recently, was
like 50% more expensive.

Arfa

 

[Eeyore]

N_Cook wrote:

Do you know the most authorative source/group, academic or industry
expert/s, on tin-pest, lead-free solder, in-service degradation of solder in
connjunction with temperature and vibration. ie those issues, as distinct
from tin whiskers aspect that seems to have more coverage.

ERA, I thin, did a report for the EU which smelt of trying to brush the evidence
under the carpet.

Graham

 

[Eeyore]

Arfa Daily wrote:

To N.Cook The place that I got my research material from was Tin Technology
Ltd with a website of www.lead-free.org The person that I spoke to at that
body, pointed me to www.dti.gov.uk/sustainability/weee/index.htm I also
spoke to a Dr Goodman at ERAT Technology Ltd

That's Paul Goodman at ERA Technology. The final report is here.
http://ec.europa.eu/environment/waste/weee/pdf/era_study_final_report.pdf

There was a simpler 30 or so page interim report I've mislaid which definitely
showed indications of problems from vibration.

Whilst assembly houses may have optimised the processes, for sure it's far more
difficult for an individual to use.

Graham

 

[Eeyore]

Eeyore wrote:

Arfa Daily wrote:

To N.Cook The place that I got my research material from was Tin Technology
Ltd with a website of www.lead-free.org The person that I spoke to at that
body, pointed me to www.dti.gov.uk/sustainability/weee/index.htm I also
spoke to a Dr Goodman at ERAT Technology Ltd

That's Paul Goodman at ERA Technology. The final report is here.
http://ec.europa.eu/environment/waste/weee/pdf/era_study_final_report.pdf

There was a simpler 30 or so page interim report I've mislaid which definitely
showed indications of problems from vibration.

Whilst assembly houses may have optimised the processes, for sure it's far more
difficult for an individual to use.

I've emailed Dr Goodman again to see if the simpler report still exists. In the
meantimes this google search gave a host of results.

" ERA interim report lead-free " without the quote marks as I tried it.

Graham

 

[Eeyore]

Ron wrote:

N_Cook wrote:
Ron <ron@lunevalleyaudio.com> wrote in message

It probly started off as a hairline crack around one of the soldered
joins, caused by repeated connecting and disconnecting. It started
'fizzling', no one noticed (or cared) until the amp failed to work by
which time there was a socking great hole in the board and a nasty
smell. It`a amazing how long a lot of musicians will put up with faulty
gear, prefering to ignore problems till the item stops working.

Doesn't really need a post mortem.


I agree that is the normal etiology and pathology, carrying on the
medico-speak. But this was a socking great burnt patch and billowing smoke
out of the 1/4 inch socket holes, that developed after sound check and
before use proper. Agreed there could have been long term, unnoticed, minor
fizzing but I've never seen this sort of damage in this sort of mains power
line circumstance.

I`m surprised, it`s a pretty common failure mode.
Bear in mind that the point of arcing usually comes before the
equipments internal mains fuse, but after the fuse in the plug top,
which is more often than not rated at 13amps.
Once the board starts to carbonise quite a large current can flow, and
the current is only flowing between two points it was intented to flow
anyway - at least initially. It doesnt take long for it to burn a hole
in a board.

I'd agree with your analysis. I have seen both hairline cracks such as you
mention and 'cold joints' caused by failure to use an appropriate soldering
temperature, or soldering time when soldering components with large thermal mass
such an IEC connector PCB pin ( pressure will keep it working for a while but
it'll finally go high resistance ). Even seen that on TO-220 devices.

Graham

 

[Eeyore]

Eeyore wrote:

Ron wrote:
N_Cook wrote:
Ron <ron@lunevalleyaudio.com> wrote in message

It probly started off as a hairline crack around one of the soldered
joins, caused by repeated connecting and disconnecting. It started
'fizzling', no one noticed (or cared) until the amp failed to work by
which time there was a socking great hole in the board and a nasty
smell. It`a amazing how long a lot of musicians will put up with faulty
gear, prefering to ignore problems till the item stops working.

Doesn't really need a post mortem.


I agree that is the normal etiology and pathology, carrying on the
medico-speak. But this was a socking great burnt patch and billowing smoke
out of the 1/4 inch socket holes, that developed after sound check and
before use proper. Agreed there could have been long term, unnoticed, minor
fizzing but I've never seen this sort of damage in this sort of mains power
line circumstance.

I`m surprised, it`s a pretty common failure mode.
Bear in mind that the point of arcing usually comes before the
equipments internal mains fuse, but after the fuse in the plug top,
which is more often than not rated at 13amps.
Once the board starts to carbonise quite a large current can flow, and
the current is only flowing between two points it was intented to flow
anyway - at least initially. It doesnt take long for it to burn a hole
in a board.

I'd agree with your analysis. I have seen both hairline cracks such as you
mention and 'cold joints' caused by failure to use an appropriate soldering
temperature, or soldering time when soldering components with large thermal mass
such an IEC connector PCB pin ( pressure will keep it working for a while but
it'll finally go high resistance ). Even seen that on TO-220 devices.

p.s. ( The TO-220 device acting as a heatsink to the solder via its leads, hence
preventing the alloying connection needed ). I've literally seen TO-220 devices
'fall out' of a PCB after a year or two leaving 3 nice rectangular holes in what
look to be perfect solder joints.

p.p.s The hairline crack around soldered joints is especially common where the
drilled hole size is not ideal ( oversize ) for the lead diameter. I have seen
manufacturers specify hole sizes very poorly with the inevitable outcome. Hence my
PCB footprints often use my own estimation of the appropriate drill size rather than
the data book one. Plenty of other people do the same.

Graham

 

[N_Cook]

Arfa Daily <arfa.daily@ntlworld.com> wrote in message
news:rVHRl.224857$5S3.114796@newsfe05.ams2...

"Meat Plow" <meat@petitmorte.net> wrote in message
news:2r31kp.ifs.17.5@news.alt.net...
On Fri, 22 May 2009 01:49:59 +0100, "Arfa Daily"
arfa.daily@ntlworld.com>wrote:


"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4A15CF3A.99BE032B@hotmail.com...


whit3rd wrote:

On May 21, 2:59 am, "N_Cook" <dive...@tcp.co.uk> wrote:
Obviously I've come acros melting/burning, starting from bad
connection
arcing , but not this amount of damage, so am requesting other
opinions.

Burning right thru the pcb for 1/2 inch around the L pin of the
IEC,
melting
of the plastic of the IEC above the burning and even the linecord
plug

Yep, ring crack around a power solder connection, generates lots of
heat.

Possible. A victim of lead-free soldering ?
http://en.wikipedia.org/wiki/Tin_pest

Note that pure tin solder degrades below 13C. Yes that's right. And
turns
to dust.
Adding a little copper doesn't stop it but slows it some but not
enough.

The EU Commission should be strung by their necks from lamp-posts for
being a
bunch of technically ignorant twats. Why do they think lead was used
in
solder in
the first place ? For fun ?

Graham


Just what I've been saying since they first mandated the hateful stuff
....

Arfa


Glad I stockpiled enough 60/40 to last me a lifetime. I could probably
sell it on Ebay for an exuberant price one day

This Tin Pest stuff sounds like a serious problem though.

60/40 is still readily available here in pretty much all of the varieties
that it always was - I got a new roll just a couple of weeks ago. What was
interesting though, is that they have jacked up the price to match -
almost
exactly - the cost of the dreaded lead-free, which up until recently, was
like 50% more expensive.

Arfa

Do you know the most authorative source/group, academic or industry
expert/s, on tin-pest, lead-free solder, in-service degradation of solder in
connjunction with temperature and vibration. ie those issues, as distinct
from tin whiskers aspect that seems to have more coverage.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

 

[Arfa Daily]

"N_Cook" <diverse@tcp.co.uk> wrote in message
news:gv8688$7c4$1@news.eternal-september.org...

Arfa Daily <arfa.daily@ntlworld.com> wrote in message
news:rVHRl.224857$5S3.114796@newsfe05.ams2...

"Meat Plow" <meat@petitmorte.net> wrote in message
news:2r31kp.ifs.17.5@news.alt.net...
On Fri, 22 May 2009 01:49:59 +0100, "Arfa Daily"
arfa.daily@ntlworld.com>wrote:


"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4A15CF3A.99BE032B@hotmail.com...


whit3rd wrote:

On May 21, 2:59 am, "N_Cook" <dive...@tcp.co.uk> wrote:
Obviously I've come acros melting/burning, starting from bad
connection
arcing , but not this amount of damage, so am requesting other
opinions.

Burning right thru the pcb for 1/2 inch around the L pin of the
IEC,
melting
of the plastic of the IEC above the burning and even the linecord
plug

Yep, ring crack around a power solder connection, generates lots of
heat.

Possible. A victim of lead-free soldering ?
http://en.wikipedia.org/wiki/Tin_pest

Note that pure tin solder degrades below 13C. Yes that's right. And
turns
to dust.
Adding a little copper doesn't stop it but slows it some but not
enough.

The EU Commission should be strung by their necks from lamp-posts for
being a
bunch of technically ignorant twats. Why do they think lead was used
in
solder in
the first place ? For fun ?

Graham


Just what I've been saying since they first mandated the hateful stuff
...

Arfa


Glad I stockpiled enough 60/40 to last me a lifetime. I could probably
sell it on Ebay for an exuberant price one day

This Tin Pest stuff sounds like a serious problem though.

60/40 is still readily available here in pretty much all of the varieties
that it always was - I got a new roll just a couple of weeks ago. What
was
interesting though, is that they have jacked up the price to match -
almost
exactly - the cost of the dreaded lead-free, which up until recently, was
like 50% more expensive.

Arfa



Do you know the most authorative source/group, academic or industry
expert/s, on tin-pest, lead-free solder, in-service degradation of solder
in
connjunction with temperature and vibration. ie those issues, as distinct
from tin whiskers aspect that seems to have more coverage.


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

I spoke by email with a couple of industry advice bodies, when I was
preparing an article on lead-free solder for a mag. I'll see if I can find
the references for them.

Arfa

 

[N_Cook]

Arfa Daily <arfa.daily@ntlworld.com> wrote in message
news:NIPRl.35858$TE3.7217@newsfe13.ams2...

"N_Cook" <diverse@tcp.co.uk> wrote in message
news:gv8688$7c4$1@news.eternal-september.org...
Arfa Daily <arfa.daily@ntlworld.com> wrote in message
news:rVHRl.224857$5S3.114796@newsfe05.ams2...

"Meat Plow" <meat@petitmorte.net> wrote in message
news:2r31kp.ifs.17.5@news.alt.net...
On Fri, 22 May 2009 01:49:59 +0100, "Arfa Daily"
arfa.daily@ntlworld.com>wrote:


"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4A15CF3A.99BE032B@hotmail.com...

I spoke by email with a couple of industry advice bodies, when I was
preparing an article on lead-free solder for a mag. I'll see if I can find
the references for them.

Arfa

I did not find , on this site, the expected date for the results of their
study

CALCE Long-Term Pb-Free Study
http://www.calce.umd.edu/lead-free/longterm.htm

Generally, it seems to be just anecdotal evidence so far


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

 

[Meat Plow]

On Sat, 23 May 2009 02:01:09 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com>wrote:

"Meat Plow" <meat@petitmorte.net> wrote in message
news:2r31kp.ifs.17.5@news.alt.net...
On Fri, 22 May 2009 01:49:59 +0100, "Arfa Daily"
arfa.daily@ntlworld.com>wrote:


"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4A15CF3A.99BE032B@hotmail.com...


whit3rd wrote:

On May 21, 2:59 am, "N_Cook" <dive...@tcp.co.uk> wrote:
Obviously I've come acros melting/burning, starting from bad
connection
arcing , but not this amount of damage, so am requesting other
opinions.

Burning right thru the pcb for 1/2 inch around the L pin of the IEC,
melting
of the plastic of the IEC above the burning and even the linecord
plug

Yep, ring crack around a power solder connection, generates lots of
heat.

Possible. A victim of lead-free soldering ?
http://en.wikipedia.org/wiki/Tin_pest

Note that pure tin solder degrades below 13C. Yes that's right. And
turns
to dust.
Adding a little copper doesn't stop it but slows it some but not enough.

The EU Commission should be strung by their necks from lamp-posts for
being a
bunch of technically ignorant twats. Why do they think lead was used in
solder in
the first place ? For fun ?

Graham


Just what I've been saying since they first mandated the hateful stuff ...

Arfa


Glad I stockpiled enough 60/40 to last me a lifetime. I could probably
sell it on Ebay for an exuberant price one day

This Tin Pest stuff sounds like a serious problem though.

60/40 is still readily available here in pretty much all of the varieties
that it always was - I got a new roll just a couple of weeks ago. What was
interesting though, is that they have jacked up the price to match - almost
exactly - the cost of the dreaded lead-free, which up until recently, was
like 50% more expensive.

Arfa

Last I bought was for copper plumbing. I tried the lead free crap and
it was laughable on 1/2 inch water pipe. I have many years experience
soldering and brazing but won't touch the lead free crap again.

 

[Arfa Daily]

"Meat Plow" <meat@petitmorte.net> wrote in message
news:2r5j0g.1n5.19.4@news.alt.net...

On Sat, 23 May 2009 02:01:09 +0100, "Arfa Daily"
arfa.daily@ntlworld.com>wrote:


"Meat Plow" <meat@petitmorte.net> wrote in message
news:2r31kp.ifs.17.5@news.alt.net...
On Fri, 22 May 2009 01:49:59 +0100, "Arfa Daily"
arfa.daily@ntlworld.com>wrote:


"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4A15CF3A.99BE032B@hotmail.com...


whit3rd wrote:

On May 21, 2:59 am, "N_Cook" <dive...@tcp.co.uk> wrote:
Obviously I've come acros melting/burning, starting from bad
connection
arcing , but not this amount of damage, so am requesting other
opinions.

Burning right thru the pcb for 1/2 inch around the L pin of the
IEC,
melting
of the plastic of the IEC above the burning and even the linecord
plug

Yep, ring crack around a power solder connection, generates lots of
heat.

Possible. A victim of lead-free soldering ?
http://en.wikipedia.org/wiki/Tin_pest

Note that pure tin solder degrades below 13C. Yes that's right. And
turns
to dust.
Adding a little copper doesn't stop it but slows it some but not
enough.

The EU Commission should be strung by their necks from lamp-posts for
being a
bunch of technically ignorant twats. Why do they think lead was used
in
solder in
the first place ? For fun ?

Graham


Just what I've been saying since they first mandated the hateful stuff
...

Arfa


Glad I stockpiled enough 60/40 to last me a lifetime. I could probably
sell it on Ebay for an exuberant price one day

This Tin Pest stuff sounds like a serious problem though.

60/40 is still readily available here in pretty much all of the varieties
that it always was - I got a new roll just a couple of weeks ago. What was
interesting though, is that they have jacked up the price to match -
almost
exactly - the cost of the dreaded lead-free, which up until recently, was
like 50% more expensive.

Arfa


Last I bought was for copper plumbing. I tried the lead free crap and
it was laughable on 1/2 inch water pipe. I have many years experience
soldering and brazing but won't touch the lead free crap again.

I have an acquaintance who is a plumber, and some long time ago when the
stuff was first becoming mandated for electronic construction work, which
was actually some time after it became so for live water systems, I asked
him how he got on with it. He told me that at first they had a lot of
problems getting it to 'stick' to a joint, and problems with leaks. He said
that they had eventually got used to it, and that they could now make joints
as good as with leaded solder. However, he said that it required rather
different techniques to those conventionally used for plumbing soldering in
that the surfaces to be joined must be *very* clean as opposed to just
fundamentally clean, and that an aggressive flux helped. He also said that
it was funny stuff to work with in that it reached its melting point very
suddenly, and then had a tendency to run out of the joint, before re-setting
very suddenly also, so no 'pasty' phase, which I guess would knock on the
head the old technique of 'wiping' a joint. Given that copper expands very
readily, it will be interesting to see if joints start breaking and leaking
in 15 years' time due to the total lack of ductility that lead-free has.
We've all seen the effects of rather more intense thermal cycling on the
short-term integrity of electronic joints. Perhaps plumbing joints are a
ticking timebomb ...


To N.Cook The place that I got my research material from was Tin Technology
Ltd with a website of www.lead-free.org The person that I spoke to at that
body, pointed me to www.dti.gov.uk/sustainability/weee/index.htm I also
spoke to a Dr Goodman at ERAT Technology Ltd

All of this was 3 years ago now, and I have not visited those sites since,
if they still exist, but they did contain some good stuff at the time, and
they might lead you where you want to go, now.

Arfa

Arfa

 

[Ron]

Eeyore wrote:

p.p.s The hairline crack around soldered joints is especially common where the
drilled hole size is not ideal ( oversize ) for the lead diameter. I have seen
manufacturers specify hole sizes very poorly with the inevitable outcome. Hence my
PCB footprints often use my own estimation of the appropriate drill size rather than
the data book one. Plenty of other people do the same.

Graham

My Dad - who taught me to solder some 50 years ago - use to say that a
good solder joint started off as a good mechanical joint.

As a teeenager, I probably spent thousands of hours wiring up
uniselectors and GPO relays with tinned copper wire and sleeving, on
every joint, the wire was either wound around the tag or passed through
a hole, if it was a lead through a circuit board, the wire was bent over
at right angles on the solder side.

We manufacturerd slot machines btw.

Ron

 

[N_Cook]

Ron <ron@lunevalleyaudio.com> wrote in message
news:Zr2dnbvp1ukNuITXnZ2dnUVZ8iSdnZ2d@bt.com...

Eeyore wrote:


p.p.s The hairline crack around soldered joints is especially common
where the
drilled hole size is not ideal ( oversize ) for the lead diameter. I
have seen
manufacturers specify hole sizes very poorly with the inevitable
outcome. Hence my
PCB footprints often use my own estimation of the appropriate drill size
rather than
the data book one. Plenty of other people do the same.

Graham



My Dad - who taught me to solder some 50 years ago - use to say that a
good solder joint started off as a good mechanical joint.

As a teeenager, I probably spent thousands of hours wiring up
uniselectors and GPO relays with tinned copper wire and sleeving, on
every joint, the wire was either wound around the tag or passed through
a hole, if it was a lead through a circuit board, the wire was bent over
at right angles on the solder side.

We manufacturerd slot machines btw.

Ron

Very true , unfortunately assembly time/cost preclude that.
Hence the notorious guitar input socket problem. The sockets used to be
wired between the chassis mounted socket and pcb , so mechanically decoupled
from routine use of the socket. Now all soldered to the board and the
insertion/removal forces are transmitted to the pcb solder joint.

--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

 

[Ron]

N_Cook wrote:

Ron <ron@lunevalleyaudio.com> wrote in message
news:Zr2dnbvp1ukNuITXnZ2dnUVZ8iSdnZ2d@bt.com...
Eeyore wrote:

p.p.s The hairline crack around soldered joints is especially common
where the
drilled hole size is not ideal ( oversize ) for the lead diameter. I
have seen
manufacturers specify hole sizes very poorly with the inevitable
outcome. Hence my
PCB footprints often use my own estimation of the appropriate drill size
rather than
the data book one. Plenty of other people do the same.

Graham


My Dad - who taught me to solder some 50 years ago - use to say that a
good solder joint started off as a good mechanical joint.

As a teeenager, I probably spent thousands of hours wiring up
uniselectors and GPO relays with tinned copper wire and sleeving, on
every joint, the wire was either wound around the tag or passed through
a hole, if it was a lead through a circuit board, the wire was bent over
at right angles on the solder side.

We manufacturerd slot machines btw.

Ron


Very true , unfortunately assembly time/cost preclude that.
Hence the notorious guitar input socket problem. The sockets used to be
wired between the chassis mounted socket and pcb , so mechanically decoupled
from routine use of the socket. Now all soldered to the board and the
insertion/removal forces are transmitted to the pcb solder joint.

Even then if you bother to bend the tags over when replacing them, the
problem is less likely to recur.

Ron

 

[Meat Plow]

On Sat, 23 May 2009 18:18:11 +0100, "Arfa Daily"
<arfa.daily@ntlworld.com>wrote:

"Meat Plow" <meat@petitmorte.net> wrote in message
news:2r5j0g.1n5.19.4@news.alt.net...
On Sat, 23 May 2009 02:01:09 +0100, "Arfa Daily"
arfa.daily@ntlworld.com>wrote:


"Meat Plow" <meat@petitmorte.net> wrote in message
news:2r31kp.ifs.17.5@news.alt.net...
On Fri, 22 May 2009 01:49:59 +0100, "Arfa Daily"
arfa.daily@ntlworld.com>wrote:


"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:4A15CF3A.99BE032B@hotmail.com...


whit3rd wrote:

On May 21, 2:59 am, "N_Cook" <dive...@tcp.co.uk> wrote:
Obviously I've come acros melting/burning, starting from bad
connection
arcing , but not this amount of damage, so am requesting other
opinions.

Burning right thru the pcb for 1/2 inch around the L pin of the
IEC,
melting
of the plastic of the IEC above the burning and even the linecord
plug

Yep, ring crack around a power solder connection, generates lots of
heat.

Possible. A victim of lead-free soldering ?
http://en.wikipedia.org/wiki/Tin_pest

Note that pure tin solder degrades below 13C. Yes that's right. And
turns
to dust.
Adding a little copper doesn't stop it but slows it some but not
enough.

The EU Commission should be strung by their necks from lamp-posts for
being a
bunch of technically ignorant twats. Why do they think lead was used
in
solder in
the first place ? For fun ?

Graham


Just what I've been saying since they first mandated the hateful stuff
...

Arfa


Glad I stockpiled enough 60/40 to last me a lifetime. I could probably
sell it on Ebay for an exuberant price one day

This Tin Pest stuff sounds like a serious problem though.

60/40 is still readily available here in pretty much all of the varieties
that it always was - I got a new roll just a couple of weeks ago. What was
interesting though, is that they have jacked up the price to match -
almost
exactly - the cost of the dreaded lead-free, which up until recently, was
like 50% more expensive.

Arfa


Last I bought was for copper plumbing. I tried the lead free crap and
it was laughable on 1/2 inch water pipe. I have many years experience
soldering and brazing but won't touch the lead free crap again.

I have an acquaintance who is a plumber, and some long time ago when the
stuff was first becoming mandated for electronic construction work, which
was actually some time after it became so for live water systems, I asked
him how he got on with it. He told me that at first they had a lot of
problems getting it to 'stick' to a joint, and problems with leaks. He said
that they had eventually got used to it, and that they could now make joints
as good as with leaded solder. However, he said that it required rather
different techniques to those conventionally used for plumbing soldering in
that the surfaces to be joined must be *very* clean as opposed to just
fundamentally clean, and that an aggressive flux helped. He also said that
it was funny stuff to work with in that it reached its melting point very
suddenly, and then had a tendency to run out of the joint, before re-setting
very suddenly also, so no 'pasty' phase, which I guess would knock on the
head the old technique of 'wiping' a joint. Given that copper expands very
readily, it will be interesting to see if joints start breaking and leaking
in 15 years' time due to the total lack of ductility that lead-free has.
We've all seen the effects of rather more intense thermal cycling on the
short-term integrity of electronic joints. Perhaps plumbing joints are a
ticking timebomb ...

Well your plumbing friend is 100% correct in that description. I
suppose if I had to do it for a living I would practice and perfect it
just as I did with leaded solder. I worked for an HVAC contractor in
my early years having gone to school for it and learned to solder and
braze copper tubing. Back then everything in an AC system was brazed
and hand made. No pre charged lines etc... I can see a lot of novices
ruining valves and other plumbing component for bath and shower by
overheating them not knowing the physical changes lead free goes
through when it heats.

To N.Cook The place that I got my research material from was Tin Technology
Ltd with a website of www.lead-free.org The person that I spoke to at that
body, pointed me to www.dti.gov.uk/sustainability/weee/index.htm I also
spoke to a Dr Goodman at ERAT Technology Ltd

All of this was 3 years ago now, and I have not visited those sites since,
if they still exist, but they did contain some good stuff at the time, and
they might lead you where you want to go, now.

Arfa

Arfa

 

[Arfa Daily]

"Ron" <ron@lunevalleyaudio.com> wrote in message
news:Zr2dnbvp1ukNuITXnZ2dnUVZ8iSdnZ2d@bt.com...

Eeyore wrote:


p.p.s The hairline crack around soldered joints is especially common
where the
drilled hole size is not ideal ( oversize ) for the lead diameter. I have
seen
manufacturers specify hole sizes very poorly with the inevitable outcome.
Hence my
PCB footprints often use my own estimation of the appropriate drill size
rather than
the data book one. Plenty of other people do the same.

Graham


My Dad - who taught me to solder some 50 years ago - use to say that a
good solder joint started off as a good mechanical joint.

As a teeenager, I probably spent thousands of hours wiring up uniselectors
and GPO relays with tinned copper wire and sleeving, on every joint, the
wire was either wound around the tag or passed through a hole, if it was a
lead through a circuit board, the wire was bent over at right angles on
the solder side.

We manufacturerd slot machines btw.

Ron

Arrrggghhh !! Dontcha just hate trying to unsolder and remove components
with bent-over legs ... ? Very true though that you should have a good
mechanical joint first. It's the way I was taught too, not quite so long
ago, but close. At college, we had to make connections to lengths of
tagstrip, without melting the insulation on the single-strand wire, as
practice pieces.

Arfa

 

[Geo]

On Sun, 24 May 2009 16:54:32 +0100, "Arfa Daily" <arfa.daily@ntlworld.com>
wrote:

Arrrggghhh !! Dontcha just hate trying to unsolder and remove components
with bent-over legs ... ? Very true though that you should have a good
mechanical joint first.

The first transistor radio (and television) pcbs were designed so that, wherever
possible, a component wire hole was /not/ in a piece of copper. This meant that
all leads had to be bent over at right angles to meet the correct piece of
copper. The great advantage of this was the ease of temporaily disconnecting a
component for test/repair. Of course this was before auto-insertion made all the
girls redundant...
(quips here)

--
Geo

 

[Eeyore]

Ron wrote:

Eeyore wrote:

p.p.s The hairline crack around soldered joints is especially common where the
drilled hole size is not ideal ( oversize ) for the lead diameter. I have seen
manufacturers specify hole sizes very poorly with the inevitable outcome. Hence my
PCB footprints often use my own estimation of the appropriate drill size rather than
the data book one. Plenty of other people do the same.

My Dad - who taught me to solder some 50 years ago - use to say that a
good solder joint started off as a good mechanical joint.

As a teeenager, I probably spent thousands of hours wiring up
uniselectors and GPO relays with tinned copper wire and sleeving, on
every joint, the wire was either wound around the tag or passed through
a hole, if it was a lead through a circuit board, the wire was bent over
at right angles on the solder side.

We manufacturerd slot machines btw.

Doubtless needed it to cope with the environment.

Graham