Arfa Daily wrote in message
...
"Arfa Daily" wrote in message
...
"N_Cook" wrote in message
...
Is anyone collecting pics?
http://home.graffiti.net/diverse:gra.../pbf_crack.jpg
My micrograph setup only allows one magnification.
This one on an amp of 2006 with the tell-tale green RoHS sticker on the
back, only in for a dodgey speakon connector. Usual looking pbf solder
that
looks as though its been in a damp shed for 10 years.
But magnified visual inspection of the pcb showed this 1/4 of a circle
crack
in developement around the pin of an 80V, 6800uF. About 1mm between X
at
pin
centre and the crack, left hand end shows the complete solder. Any
guesses
how long before total failure if unattended to ?
I suppose the purists here would say leave it alone, as it is what the
designer/manufacturer specified.
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/
Careful ....
Arfa
Friend of mine rang me yesterday. He is an electronics engineer that works
on fancy amplifiers used in mass spectrometry. These are mostly quite old
as
these things go on for ever, and the amps and things are just repaired and
recalibrated, so he has not had to have much if any experience with the
dreaded lead-free. A friend of his brought him a portable CD player to
look
at, which had apparently been working without any signs of trouble or
intermittency, then just stopped.
My friend was amazed when he took the back off. An IC just fell out onto
the
bench. He couldn't believe that any production soldering could be so poor
that this could happen, and he was ringing me to see if this was the sort
of
thing that we at the sharp end of this technology, were suffering. He was
totally gobsmacked when I told him that was exactly the sort of thing we
were experiencing, and his comment was "no wonder the military and
avionics
people won't use it !"
Makes you wonder how many other high-end engineers like my friend, have so
far been shielded from the stuff, so have not had any dissenting voice in
the forum ...
Arfa
I've not seen a loose IC but I was surprised to find the simplest of
components loose once - a pbf "soldered" wire link, ordinary 1/4W resistor
gauge of wire. I'd like to know what that whitish-grey powdery deposit on
the solder is, that makes these boards look as though they've been in a damp
shed for years. Is it tin-pest, coming to the surface, the powdery allotrope
of tin? that even medieval church organ builders were aware of.
--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/