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/

"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

"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

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/

I see its the work of the devil, just googling, the first one
http://dwb.unl.edu/Teacher/NSF/C10/C...m/library/week
ly/aa040300a.htm

"The gradual disintegration of shiny tin metal into a crumbly, gray powder
was observed hundreds of years ago on tin organ pipes housed in unheated
northern European cathedrals. With allotropy unknown, the phenomenon was
attributed to the work of the Devil and was variously denoted by the terms
tin disease, tin pest, tin blight, or tin plague. The reaction is
autocatalytic; in other words, the presence of the gray alpha-tin
accelerates the process. Tin disease manifests itself in pure tin. Antimony,
bismuth, or lead retards this transformation. Tin alloys are thus more
resistant to tin disease."


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

"N_Cook" wrote in message
...
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/



I've seen a number of examples of ICs hanging on by a couple of pins, and
have had a few where an IC has fallen off completely. Used to be a big
problem with the audio IC in several Sony portable MD players, and also in a
particular DAB radio that I used to have dealings with.

Arfa

I was reading up recently concerning damage due to the excessive heat for
PbF soldering of pcbs. The most common fallout in immediate post-production
test is multilayer ceramic caps

Is this delayed damage on this German made Dynacord mixer amp, definitely
using pbf construction.?
A 100nF, 100V cap incinerated itself , in an area that did not affect
routine use of the amp.
The failure of the amp was due to another of this batch of capacitors with
less than 20V standing DC, going ohmic, measuring of order 20K to 30K with a
DVM when I measured it but varying considerably.
in the parts list as
KO-KER 0.10MF 100V 20% cap ceramic 100nF
it is mustard yellow epoxy cased, axial leaded, 2.2mm diameter, 3.5mm long
at longest axial dimension, with markings (requiring x30 microscope to read,
and not that clear, so maybe wrong transcription)
R1E
104
MGR
619

104 for 100nF and 619 for week 19 of 2006, R1E for 100V ?
I've not found the manufacturer yet under KO-KER or MGR yet, but I assume
from the size that they are multilayer ceramic.

I can of course replace these 2 but what about the remaining 40 or so?


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

N_Cook wrote in message
...
I was reading up recently concerning damage due to the excessive heat for
PbF soldering of pcbs. The most common fallout in immediate
post-production
test is multilayer ceramic caps

Is this delayed damage on this German made Dynacord mixer amp, definitely
using pbf construction.?
A 100nF, 100V cap incinerated itself , in an area that did not affect
routine use of the amp.
The failure of the amp was due to another of this batch of capacitors with
less than 20V standing DC, going ohmic, measuring of order 20K to 30K with
a
DVM when I measured it but varying considerably.
in the parts list as
KO-KER 0.10MF 100V 20% cap ceramic 100nF
it is mustard yellow epoxy cased, axial leaded, 2.2mm diameter, 3.5mm long
at longest axial dimension, with markings (requiring x30 microscope to
read,
and not that clear, so maybe wrong transcription)
R1E
104
MGR
619

104 for 100nF and 619 for week 19 of 2006, R1E for 100V ?
I've not found the manufacturer yet under KO-KER or MGR yet, but I assume
from the size that they are multilayer ceramic.

I can of course replace these 2 but what about the remaining 40 or so?


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




the sort of caps involved, not this company necessarily
http://img.en.china.cn/1/0,0,434,317...9,b831706c.jpg

N_Cook wrote in message
...
N_Cook wrote in message
...
I was reading up recently concerning damage due to the excessive heat
for
PbF soldering of pcbs. The most common fallout in immediate
post-production
test is multilayer ceramic caps

Is this delayed damage on this German made Dynacord mixer amp,
definitely
using pbf construction.?
A 100nF, 100V cap incinerated itself , in an area that did not affect
routine use of the amp.
The failure of the amp was due to another of this batch of capacitors
with
less than 20V standing DC, going ohmic, measuring of order 20K to 30K
with
a
DVM when I measured it but varying considerably.
in the parts list as
KO-KER 0.10MF 100V 20% cap ceramic 100nF
it is mustard yellow epoxy cased, axial leaded, 2.2mm diameter, 3.5mm
long
at longest axial dimension, with markings (requiring x30 microscope to
read,
and not that clear, so maybe wrong transcription)
R1E
104
MGR
619

104 for 100nF and 619 for week 19 of 2006, R1E for 100V ?
I've not found the manufacturer yet under KO-KER or MGR yet, but I
assume
from the size that they are multilayer ceramic.

I can of course replace these 2 but what about the remaining 40 or so?


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




the sort of caps involved, not this company necessarily
http://img.en.china.cn/1/0,0,434,317...9,b831706c.jpg




I forgot about the mixer part, 103 of these same caps in the whole amp. So 2
failed in 3 years, where's a statistician when you need one ?

N_Cook wrote in message
...
N_Cook wrote in message
...
I was reading up recently concerning damage due to the excessive heat
for
PbF soldering of pcbs. The most common fallout in immediate
post-production
test is multilayer ceramic caps

Is this delayed damage on this German made Dynacord mixer amp,
definitely
using pbf construction.?
A 100nF, 100V cap incinerated itself , in an area that did not affect
routine use of the amp.
The failure of the amp was due to another of this batch of capacitors
with
less than 20V standing DC, going ohmic, measuring of order 20K to 30K
with
a
DVM when I measured it but varying considerably.
in the parts list as
KO-KER 0.10MF 100V 20% cap ceramic 100nF
it is mustard yellow epoxy cased, axial leaded, 2.2mm diameter, 3.5mm
long
at longest axial dimension, with markings (requiring x30 microscope to
read,
and not that clear, so maybe wrong transcription)
R1E
104
MGR
619

104 for 100nF and 619 for week 19 of 2006, R1E for 100V ?
I've not found the manufacturer yet under KO-KER or MGR yet, but I
assume
from the size that they are multilayer ceramic.

I can of course replace these 2 but what about the remaining 40 or so?


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




the sort of caps involved, not this company necessarily
http://img.en.china.cn/1/0,0,434,317...9,b831706c.jpg



I've not fully found out why MLCCs fail due to the extra heat of PbF. Its to
do with thermal mass of the ceramic , but failure would seem to be cracking
rather than going ohmic. Or does the cracking allow adjascent metalisations
to bridge or approach very close. These were wire ended not SM, and failed
by going progressively ohmic, the one that burnt out did not blow 1.6 amp
fuses with 40 volt over it, the other one was down to 20 to 30K ohmic
causing problem.


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

This seems to explain the mechanism
http://www.era.co.uk/news/rfa_feature_07b.asp
but that is for SM and I've not managed to confirm the ones I'm dealing with
are definitely MLCC, how/why round format ?
So metalalisation creep down the cracks is the mechanism, so would take
years to develop.


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