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Soldering: a technical question

M

moonlite

Jan 1, 1970
0
I'm working on a high end DVD player. It seems I am unable to make the
solder joints on the board take solder no matter what I do. I even
tried to add solder to the joints hoping that would help in the
desoldering process but they simply won't take. Is it possible this
board is manufactured differently to make servicing not possible
without specialized tools only ASC's have them ?

moonlite
 
A

Arfa Daily

Jan 1, 1970
0
moonlite said:
I'm working on a high end DVD player. It seems I am unable to make the
solder joints on the board take solder no matter what I do. I even
tried to add solder to the joints hoping that would help in the
desoldering process but they simply won't take. Is it possible this
board is manufactured differently to make servicing not possible
without specialized tools only ASC's have them ?

moonlite

If it is an up to date machine, then it will be manufactured using the
dreadful new-fangled save-the-planet brigade's lead-free solder. In order to
repair it with any hope of long term chemical stability of any reworked
joints, you will need to be using using lead-free solder to rework them, and
in order to do this, your iron will need to be around 30 deg C hotter than
it needs to be for standard leaded solder. If you look carefully at the
board with a strong magnifier, you will likely see that every joint has a
dull grey dry ( american " cold " )look to it. Welcome to the world of
lead-free ...

Just as a matter of interest, what is the machine, what is the problem that
you are trying to fix, and what soldering equipment are you trying to use
for the job ?

Arfa
 
N

N Cook

Jan 1, 1970
0
Arfa Daily said:
If it is an up to date machine, then it will be manufactured using the
dreadful new-fangled save-the-planet brigade's lead-free solder. In order to
repair it with any hope of long term chemical stability of any reworked
joints, you will need to be using using lead-free solder to rework them, and
in order to do this, your iron will need to be around 30 deg C hotter than
it needs to be for standard leaded solder. If you look carefully at the
board with a strong magnifier, you will likely see that every joint has a
dull grey dry ( american " cold " )look to it. Welcome to the world of
lead-free ...

Just as a matter of interest, what is the machine, what is the problem that
you are trying to fix, and what soldering equipment are you trying to use
for the job ?

Arfa

Are things going to get that bad?
I've not met this new health & safety junk yet, eg at the moment repairing a
1974 Rotel amp
 
M

moonlite

Jan 1, 1970
0
Arfa said:
If it is an up to date machine, then it will be manufactured using the
dreadful new-fangled save-the-planet brigade's lead-free solder. In order to
repair it with any hope of long term chemical stability of any reworked
joints, you will need to be using using lead-free solder to rework them, and
in order to do this, your iron will need to be around 30 deg C hotter than
it needs to be for standard leaded solder. If you look carefully at the
board with a strong magnifier, you will likely see that every joint has a
dull grey dry ( american " cold " )look to it. Welcome to the world of
lead-free ...

Just as a matter of interest, what is the machine, what is the problem that
you are trying to fix, and what soldering equipment are you trying to use
for the job ?

Arfa


Thank you very much for this reply! I knew something was up because
I've been soldering for a long time but never seen this. The unit is a
Samsung, very fancy DVD player. Sometimes it freezes so I decided to
give the main board a look. I did find what appeared to be, like you
said, cold solder joints. I guess that's not "cold" after all. Is this
lead free solder sold anywhere ?

moonlite
 
I

ian field

Jan 1, 1970
0
moonlite said:
Thank you very much for this reply! I knew something was up because
I've been soldering for a long time but never seen this. The unit is a
Samsung, very fancy DVD player. Sometimes it freezes so I decided to
give the main board a look. I did find what appeared to be, like you
said, cold solder joints. I guess that's not "cold" after all. Is this
lead free solder sold anywhere ?

moonlite

Where are you? - Maplin sell it in the UK, its actually becoming hard to
find lead/tin solder!
 
N

N Cook

Jan 1, 1970
0
I niaively thought that if I should come across such a pcb with this
lead-free stuff and a cold joint then all I'd have to do was remake the
joint by adding traditional solder into the mix.
But I take it now that they are incompatible, which presumably means that
even solder sucking away all the original from component lead lead and pad
would still leave contaminated surfaces that still would not take
traditional solder for a more durable joint - opinions/knowledge anyone ?
 
I

ian field

Jan 1, 1970
0
N Cook said:
I niaively thought that if I should come across such a pcb with this
lead-free stuff and a cold joint then all I'd have to do was remake the
joint by adding traditional solder into the mix.
But I take it now that they are incompatible, which presumably means that
even solder sucking away all the original from component lead lead and pad
would still leave contaminated surfaces that still would not take
traditional solder for a more durable joint - opinions/knowledge anyone ?

Most of the monitors I used to repair had been assembled with lead free for
a couple of decades - this was by far the most common cause of failure!!!

As of yet I have never bought any lead free solder and the only problem I've
had is if the lead free isn't sufficiently diluted with lead/tin, it remains
"stringy" and causes solder bridges! Use plenty of flux but be mindful of
the measures needed to clean it off after!!!
 
C

Claude

Jan 1, 1970
0
Arfa said:
If it is an up to date machine, then it will be manufactured using the
dreadful new-fangled save-the-planet brigade's lead-free solder. In order to
repair it with any hope of long term chemical stability of any reworked
joints, you will need to be using using lead-free solder to rework them, and
in order to do this, your iron will need to be around 30 deg C hotter than
it needs to be for standard leaded solder. If you look carefully at the
board with a strong magnifier, you will likely see that every joint has a
dull grey dry ( american " cold " )look to it. Welcome to the world of
lead-free ...

Just as a matter of interest, what is the machine, what is the problem that
you are trying to fix, and what soldering equipment are you trying to use
for the job ?

Arfa
I wouldn't be surprised if they are using metallic glue (cold) for
electrical connections.

--

50% of all statistics are wrong. The rest don't matter.


Claude Hopper
 
A

Arfa Daily

Jan 1, 1970
0
moonlite said:
Thank you very much for this reply! I knew something was up because
I've been soldering for a long time but never seen this. The unit is a
Samsung, very fancy DVD player. Sometimes it freezes so I decided to
give the main board a look. I did find what appeared to be, like you
said, cold solder joints. I guess that's not "cold" after all. Is this
lead free solder sold anywhere ?

moonlite

Well, it's sold everywhere here now, and regular leaded solder is becoming
more difficult to obtain, but I'm assuming that you are on the US side of
the Atlantic ?? The Americans, as I understand it, have not been so keen to
adopt this lead-free technology as the far east and Europe have. It's now
law here under a directive called RoHS ( Restriction of Hazardous
Substances ). The US military, for instance, flatly refuse to use it on
reliability grounds. Over here, the avionics and medical instrument
industries have been granted exemptions, and decisions on many others are
pending. Never-the-less, the far east have been manufacturing in this
technology for about 3 years or so now, so I would guess that most if not
all of the US imports of these products from the far east locations, are
built with lead-free. This being the case, I would expect that lead-free
solder would be readily available. Indeed, Sony for instance, have insisted
that their official dealers over here, use ONLY lead-free to repair ALL of
their products, for the last 2 years, irrespective of whether they were
originally built in leaded or lead-free. As you can imagine, this has gone
down like a lead ( Ha ! ) balloon in service departments ... The solder
industry itself seems unable to make up its mind as to whether mixing leaded
and unleaded solder causes a long term problem. Half say you shouldn't, half
say no problem. I recently wrote an article for a magazine on this very
subject, and took some expert advice on this point, and his reckoning was
don't mix if you don't want a long-term unstable joint.

Anyway, on your Sammy problem. It is rare for a genuine electronic fault to
be responsible for any kind of freezing. Commonly, it is caused by either a
defective / worn laser, or a mechanical issue with the laser sled transport.
As a first move, ensure that the laser moves silky smooth the whole way from
one end of its slides to the other. I had a Sammy last week that had a
tendency to freeze up about 30 - 40 minutes into a disc. The cause was
distortion of the plastic runner that one side of the laser ran on. You
could feel the laser get tight as you moved it towards the back of the deck.
This was cured by slight rubbing down of the plastic with very fine carb
paper, followed by metal polish. You can also get poor sled movement as a
result of the pinion on the sled motor splitting. If you move the laser by
hand, you get a bump-bump-bump as the pinion rotates past the split.

Sad to say though that the majority of freezing problems are down to the
laser itself. If the laser is iffy, it will have a lot more trouble reading
home-burns than commercial pressings, and will tend to freeze on them more
readily. Conversely, an audio CD will normally play faultlessly. Not an
absolutely definative test for laser condition, but usually a good
indicator.

Arfa
 
M

moonlite

Jan 1, 1970
0
Arfa said:
Well, it's sold everywhere here now, and regular leaded solder is becoming
more difficult to obtain, but I'm assuming that you are on the US side of
the Atlantic ?? The Americans, as I understand it, have not been so keen to
adopt this lead-free technology as the far east and Europe have. It's now
law here under a directive called RoHS ( Restriction of Hazardous
Substances ). The US military, for instance, flatly refuse to use it on
reliability grounds. Over here, the avionics and medical instrument
industries have been granted exemptions, and decisions on many others are
pending. Never-the-less, the far east have been manufacturing in this
technology for about 3 years or so now, so I would guess that most if not
all of the US imports of these products from the far east locations, are
built with lead-free. This being the case, I would expect that lead-free
solder would be readily available. Indeed, Sony for instance, have insisted
that their official dealers over here, use ONLY lead-free to repair ALL of
their products, for the last 2 years, irrespective of whether they were
originally built in leaded or lead-free. As you can imagine, this has gone
down like a lead ( Ha ! ) balloon in service departments ... The solder
industry itself seems unable to make up its mind as to whether mixing leaded
and unleaded solder causes a long term problem. Half say you shouldn't, half
say no problem. I recently wrote an article for a magazine on this very
subject, and took some expert advice on this point, and his reckoning was
don't mix if you don't want a long-term unstable joint.

Anyway, on your Sammy problem. It is rare for a genuine electronic fault to
be responsible for any kind of freezing. Commonly, it is caused by either a
defective / worn laser, or a mechanical issue with the laser sled transport.
As a first move, ensure that the laser moves silky smooth the whole way from
one end of its slides to the other. I had a Sammy last week that had a
tendency to freeze up about 30 - 40 minutes into a disc. The cause was
distortion of the plastic runner that one side of the laser ran on. You
could feel the laser get tight as you moved it towards the back of the deck.
This was cured by slight rubbing down of the plastic with very fine carb
paper, followed by metal polish. You can also get poor sled movement as a
result of the pinion on the sled motor splitting. If you move the laser by
hand, you get a bump-bump-bump as the pinion rotates past the split.

Sad to say though that the majority of freezing problems are down to the
laser itself. If the laser is iffy, it will have a lot more trouble reading
home-burns than commercial pressings, and will tend to freeze on them more
readily. Conversely, an audio CD will normally play faultlessly. Not an
absolutely definative test for laser condition, but usually a good
indicator.

Arfa

Arfa, I can't thank you enough for this info and for taking the time to
explain this lead-free issue. I am sure the readers of this post also
appreciate your effort!
 
M

moonlite

Jan 1, 1970
0
Arfa said:
Well, it's sold everywhere here now, and regular leaded solder is becoming
more difficult to obtain, but I'm assuming that you are on the US side of
the Atlantic ?? The Americans, as I understand it, have not been so keen to
adopt this lead-free technology as the far east and Europe have. It's now
law here under a directive called RoHS ( Restriction of Hazardous
Substances ). The US military, for instance, flatly refuse to use it on
reliability grounds. Over here, the avionics and medical instrument
industries have been granted exemptions, and decisions on many others are
pending. Never-the-less, the far east have been manufacturing in this
technology for about 3 years or so now, so I would guess that most if not
all of the US imports of these products from the far east locations, are
built with lead-free. This being the case, I would expect that lead-free
solder would be readily available. Indeed, Sony for instance, have insisted
that their official dealers over here, use ONLY lead-free to repair ALL of
their products, for the last 2 years, irrespective of whether they were
originally built in leaded or lead-free. As you can imagine, this has gone
down like a lead ( Ha ! ) balloon in service departments ... The solder
industry itself seems unable to make up its mind as to whether mixing leaded
and unleaded solder causes a long term problem. Half say you shouldn't, half
say no problem. I recently wrote an article for a magazine on this very
subject, and took some expert advice on this point, and his reckoning was
don't mix if you don't want a long-term unstable joint.

Anyway, on your Sammy problem. It is rare for a genuine electronic fault to
be responsible for any kind of freezing. Commonly, it is caused by either a
defective / worn laser, or a mechanical issue with the laser sled transport.
As a first move, ensure that the laser moves silky smooth the whole way from
one end of its slides to the other. I had a Sammy last week that had a
tendency to freeze up about 30 - 40 minutes into a disc. The cause was
distortion of the plastic runner that one side of the laser ran on. You
could feel the laser get tight as you moved it towards the back of the deck.
This was cured by slight rubbing down of the plastic with very fine carb
paper, followed by metal polish. You can also get poor sled movement as a
result of the pinion on the sled motor splitting. If you move the laser by
hand, you get a bump-bump-bump as the pinion rotates past the split.

Sad to say though that the majority of freezing problems are down to the
laser itself. If the laser is iffy, it will have a lot more trouble reading
home-burns than commercial pressings, and will tend to freeze on them more
readily. Conversely, an audio CD will normally play faultlessly. Not an
absolutely definative test for laser condition, but usually a good
indicator.

Arfa

Arfa, I can't thank you enough for this info and for taking the time to
explain this lead-free issue. I am sure the readers of this post also
appreciate your effort!
 
A

Andy Cuffe

Jan 1, 1970
0
I niaively thought that if I should come across such a pcb with this
lead-free stuff and a cold joint then all I'd have to do was remake the
joint by adding traditional solder into the mix.
But I take it now that they are incompatible, which presumably means that
even solder sucking away all the original from component lead lead and pad
would still leave contaminated surfaces that still would not take
traditional solder for a more durable joint - opinions/knowledge anyone ?

I've never had any problems working with lead free boards. The solder
is a little harder to remove, but it should take regular Sn/Pb solder
fine. I don't know what the long term reliability will be, but
everything looks fine and I haven't seen any problems yet.

It sounds like your soldering iron just isn't powerful enough. Multi
layer boards with lead free solder will require a much more powerful
soldering iron than you can get away with on a single sided board. I
highly recommend a 40W or greater temperature controlled soldering
station for working on any modern electronics.

Andy Cuffe

[email protected]
 
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