Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #21   Report Post  
Old July 25th 07, 01:22 PM posted to sci.electronics.design,sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 102
Default So what's the truth about lead-free solder ?

On a sunny day (Wed, 25 Jul 2007 12:28:58 +0100) it happened "N Cook"
wrote in :

Arfa Daily wrote in message
...

"Eeyore" wrote in message
...


Spurious Response wrote:

Eeyore wrote:
"Leeper" wrote:

t is really application and chip package specific,

Bull****. Lead based solder alloys are superior in damn near all
electronic realms, and there is no configuration where they would

not
be
other than high end commercial and military applications, and they
certainly do not include Tin.

Whilst I don't disagree with you, where's the hard comparative data ?

Considering the fact that we have 5 decade old circuit cards still
operating perfectly, and that we already know what alloys containing

Tin
which is not bound by Lead do over time and temperature cycling, I do

not
think that precise numerical analysis is even needed on such a

profoundly
lopsided issue.

Whilst I agree with you, bureacrats tend not to be very receptive to
anecdotal
comment. And make no mistake, the bureacrats are the ones in control of
this.

Graham



I have just this minute finished repairing a Panasonic DAB / FM radio

which
was dying as soon as it was switched on, with a "F76 Pdet" error in the
display. I took this to be "power detect", which seemed reasonable, given
the symptoms. When I took the main board out to have a look at the
underside, I found the power supply section riddled with poor and
'cracked-right-round' lead-free solder joints ( the board actually has
"PbF" silk-screened on it ). The poor joints were particularly well

defined
on the main free-air cooled regulator transistor, which is obviously

subject
to thermal cycling.

I reworked all the joints with lead-free, as that is what the RoHS
legislation legally charges me to do as a commercial repair outfit, but

boy,
the temptation was strong to just reach for the leaded solder, and do the
job 'properly' ...

Arfa



What was the chipcode dates on that DAB ?
No more than 2 years old no doubt.

If you had not repaired it than also no doubt it would have ended in
landfill taking with it ,perhaps not lead, but antimony, bismuth, tin,
copper, barium , phthalates etc


Actually, in the long ago past when I had the TV repair shop, I had exactly
the same problem on old tube connectors in PCBs and also on inductiors, and old
Philips K8 connectors, some after 2 years too I think.
With leaded solder.
This is also also an issue of better connections, some that allow some movement,
like WIRES for example...
I mean use flexible wires to connect the hot components to a PCB.
That defeats the idea of PCB perhaps.
But I only wanted to point out that that thermal effect is also present in leaded
solder.
It could be worse in leadfree, but you'd have to test in the same setup.
He *could* have resoldered one with 60/40 and when it comes back in 2 years
see which ones gave way ;-)




workin gas TV repair

  #22   Report Post  
Old July 25th 07, 01:42 PM posted to sci.electronics.design,sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Sep 2006
Posts: 2,770
Default So what's the truth about lead-free solder ?



Jan Panteltje wrote:

Actually, in the long ago past when I had the TV repair shop, I had exactly
the same problem on old tube connectors in PCBs and also on inductiors, and old
Philips K8 connectors, some after 2 years too I think.
With leaded solder.


The temperature cycles would have been rather higher methinks.

Graham

  #23   Report Post  
Old July 25th 07, 01:43 PM posted to sci.electronics.design,sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Sep 2006
Posts: 2,770
Default So what's the truth about lead-free solder ?



Jan Panteltje wrote:

He *could* have resoldered one with 60/40


No, that's illegal per the rules from the idiots in Brussels. It could result in a
fine of 2000.

Graham

  #24   Report Post  
Old July 25th 07, 02:52 PM posted to sci.electronics.design,sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2007
Posts: 8
Default So what's the truth about lead-free solder ?

On Tue, 24 Jul 2007 23:42:47 +0100, Eeyore
wrote:

The debate about lead free solders seem to be nearly as politically charged as
that about anthropogenic global warming and a casualty seems to be useful data.

I've read plenty of comments to the effect that lead-free is less reliable in
the long term (vibration seems to be a key weakness AIUI - maybe also thermal
cycling) which presumably explains the exemptions for certain categories, yet
I've also seen some studies that claim it can out-perform lead containing
solders.

Is there any real hard and fast information out there that one can rely on ?

Graham


Don't look to this newsgroup for factual info on lead free! Instead
look at actual test results in the trade publications such as SMT
magazine:
http://smt.pennnet.com/home.cfm
They have published numerous tests comparing various lead free
materials and processes with tin-lead. Some lead free materials and
processes are better than others (no surprise) and picking the best
one for your situation is non-trivial.

My nutshell summary of the published test results is that lead free is
significantly harder to do right than tin-lead, requiring tighter
process controls, but if done right it can be more reliable than
tin-lead for non-shock situations. Lead free is harder, stronger and
more brittle than tin-lead so tin-lead will deform plastically under
high shock when lead free will break, however lead free will withstand
more hot-cold cycles than before failure than tin-lead (better fatigue
resistance). So you need to know what the significant failure
mechanisms are in your design to pick the most reliable materials.

Glen
  #25   Report Post  
Old July 25th 07, 03:24 PM posted to sci.electronics.design,sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2007
Posts: 4
Default So what's the truth about lead-free solder ?




Spurious Response wrote:

reprocessing lead, and lead alloys is far easier and less
costly than mining it.


So all those owners of lead mines are wasting all that
money doing things the more expensive way as a public
service?



  #26   Report Post  
Old July 25th 07, 04:33 PM posted to sci.electronics.design,sci.electronics.repair
mpm mpm is offline
external usenet poster
 
First recorded activity by DIYBanter: Jul 2007
Posts: 14
Default So what's the truth about lead-free solder ?

On Jul 25, 3:42?am, "N Cook" wrote:

Follow the derogations/exemptions.
Military , aerospace & medical do have derogation from WEEE and RoSH, but
can anyone nail down precisely why they are exempted.


I suspect it is because these fields are considered "life-safety"
fields.
Even ordinance, when you think of it in terms of friendly fire
incidents.
They probably just don't want to recertify their processes, or don't
have the time to do it right.

But the "Truth"?
That's much more elusive.
Does RoHS result in a better environment? I don't know, but I doubt
it.
The sheer number of TV sets that will be obsoleted in the coming years
due to the migration to Digital Television will probably swamp the
RoHS "gains" by orders of magnitude.

Ditto for the batteries used in some electric cars, and the US's
(likely?) ultimate reliance on it's vast coal reserves to power all
this crap. And that's if Global Warming doesn't get us first...

Bottom line: I don't think the environment gives a sh^t about RoHS,
or WEEE.
I think we need fewer people, and less "disposable" crap from China.

-mpm

  #27   Report Post  
Old July 25th 07, 04:57 PM posted to sci.electronics.design,sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 102
Default So what's the truth about lead-free solder ?

On a sunny day (Wed, 25 Jul 2007 08:33:12 -0700) it happened mpm
wrote in
.com:

On Jul 25, 3:42?am, "N Cook" wrote:

Follow the derogations/exemptions.
Military , aerospace & medical do have derogation from WEEE and RoSH, but
can anyone nail down precisely why they are exempted.


I suspect it is because these fields are considered "life-safety"
fields.
Even ordinance, when you think of it in terms of friendly fire
incidents.
They probably just don't want to recertify their processes, or don't
have the time to do it right.

But the "Truth"?
That's much more elusive.
Does RoHS result in a better environment? I don't know, but I doubt
it.
The sheer number of TV sets that will be obsoleted in the coming years
due to the migration to Digital Television will probably swamp the
RoHS "gains" by orders of magnitude.


Right, I turned in a portable TV last week.
This one was about 30 years old (seventies), and was still working OK,
but no analog transmissions here anymore, all you get is nice equal
distributed noise when tuning in to a digital station.

  #28   Report Post  
Old July 25th 07, 06:29 PM posted to sci.electronics.design,sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2007
Posts: 19
Default So what's the truth about lead-free solder ?

On Tue, 24 Jul 2007 23:42:47 +0100, Eeyore wrote:

The debate about lead free solders seem to be nearly as politically
charged as that about anthropogenic global warming and a casualty seems to
be useful data.

I've read plenty of comments to the effect that lead-free is less reliable
in the long term (vibration seems to be a key weakness AIUI - maybe also
thermal cycling) which presumably explains the exemptions for certain
categories, yet I've also seen some studies that claim it can out-perform
lead containing solders.

Is there any real hard and fast information out there that one can rely on
?

Graham


Dr Howard Johnson (High Speed Digital Design) had this article in
his email newsletter (and posted on his site). Interesting read.
Rollback RoHS: http://www.sigcon.com/Pubs/news/10_01.htm


--
Joe Chisolm
Marble Falls, TX

  #29   Report Post  
Old July 25th 07, 06:56 PM posted to sci.electronics.design,sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2006
Posts: 102
Default So what's the truth about lead-free solder ?

On a sunny day (Wed, 25 Jul 2007 12:29:00 -0500) it happened Joe Chisolm
wrote in :


Dr Howard Johnson (High Speed Digital Design) had this article in
his email newsletter (and posted on his site). Interesting read.
Rollback RoHS: http://www.sigcon.com/Pubs/news/10_01.htm


Well seems [all] we have to [do is] make some traces .65mm apart :-)
  #30   Report Post  
Old July 25th 07, 07:02 PM posted to sci.electronics.design,sci.electronics.repair
external usenet poster
 
First recorded activity by DIYBanter: Jul 2007
Posts: 1
Default So what's the truth about lead-free solder ?

On Jul 25, 1:29 pm, Joe Chisolm wrote:
On Tue, 24 Jul 2007 23:42:47 +0100, Eeyore wrote:
The debate about lead free solders seem to be nearly as politically
charged as that about anthropogenic global warming and a casualty seems to
be useful data.


I've read plenty of comments to the effect that lead-free is less reliable
in the long term (vibration seems to be a key weakness AIUI - maybe also
thermal cycling) which presumably explains the exemptions for certain
categories, yet I've also seen some studies that claim it can out-perform
lead containing solders.


Is there any real hard and fast information out there that one can rely on
?


The main issue for lead free in military and aerospace electronics is
tin whiskers. Tin solder will
grow conductive whiskers that even penetrate conformal coatings. In
low power circuit,
the whisker will short something out. In a high power circuit, it
might burn up like a fuse,
but if it happens in a satellite (no atmospheric pressure) the little
whisker will cause
a plasma arc capable of passing huge amounts of current.

We in the defense electonics industry fight with this issue every day
and the information
is very confusing. Parts turn lead free midstream in production and
seems impossible to
keep tack of it. Every company is dealing with it differently. We stay
away from certain
finishes like bright tin and look at the spacing of components and
coatings on our boards.
This can mitigate some of the reliability risks of lead free.

If high-rel is of upmost importance, we struggle to find tin-lead
parts.



Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Yet more on lead-free solder n cook Electronics Repair 11 August 12th 07 03:12 AM
lead free solder with voc free water base bick Electronics Repair 11 May 17th 07 04:56 PM
lead free solder [email protected] Electronics Repair 11 September 2nd 06 06:36 PM
Lead-Free vs. 63/37 tin/lead solder [email protected] Electronics Repair 28 June 17th 06 12:29 PM
Lead Free solder Michael Chare UK diy 38 March 4th 06 04:56 PM


All times are GMT +1. The time now is 05:36 PM.

Powered by vBulletin® Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Copyright 2004-2019 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"

 

Copyright © 2017