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