Antony Gelberg wrote:

Hi,

I know this should be simple but isn't. I need to resolder a DC power
connector on a laptop, due to dry joints.

I can't find my old, rarely used soldering iron, so I went to Maplin and
bought their cheapo 30W soldering iron.
http://www.maplin.co.uk/module.aspx?...32909&doy=13m6

I would have thought that is good enough for PCB soldering, but I can
barely
get the old solder on the board to melt, let alone re-solder the joint. I
can't work like this, I'm going to arse about for hours and still not get
it
done properly. Is the problem likely to be the fine point nib that it
came
with? I have always used flat-tip bits in the past. Or is the Maplin
iron crap, and should I have bought the Antek 30W instead -
http://www.maplin.co.uk/Module.aspx?...ce=14&doy=13m6 ?

All advice appreciated.


Antony,

If you can borrow a temperature controlled iron, preferably one in the
45-50watt region, with a fairly broad tip, you should be able to do the job
fairly easily.

What is happening is the large area of the multilayer PCB, combined with the
rather large track area, is siphoning away the heat from the tip and
chilling it. The iron is not temperature controlled so cannot compensate,
so its temperature drops below the required heat to melt solder.

If you keep trying with your iron, you will soon destroy the socket, board
and PCB pads- the job must be done quickly with a hot iron. I have replaced
several laptop power connectors and feel that a cheap hobbyist's iron in
the majority of cases would be quite inadequate.


Try eBay- I've seen old Weller magnastat soldering stations for about 15
UKP. Usually tatty to look at but they do a great job. I still use one
myself! The temperature is set by tip selection, and there's not much they
can't do with a hot tip fitted. Alternatively there's occasionally Antex
stations with user-variable temperature dials which go for a reasonable
amount. If you intend on servicing your own stuff you really need a
temperature controlled iron.

I should mention that I also tried my 100W soldering gun, like this one:
http://tinyurl.com/2z8ehn .

No luck here, but then I have always hated this tool and never been able
to
use it effectively. It's rated for 12 seconds use in a minute (don't know
what happens if you go above that), but takes about 9 seconds to even get
hot
enough to melt solder. Are these crap, or am I not using the thing
properly?


Soldering guns are OK for the appropriate job but not really for PCB use
because they can only administer very high heat for short bursts and need
cooling off time before they can be operated again.

To answer your question- exceeding the time will burn out the transformer
inside! The one I once used went off with quite a loud pop!

Morse

If you can borrow a temperature controlled iron, preferably one in the
45-50watt region, with a fairly broad tip, you should be able to do the
job
fairly easily.

What is happening is the large area of the multilayer PCB, combined with
the
rather large track area, is siphoning away the heat from the tip and
chilling it. The iron is not temperature controlled so cannot compensate,
so its temperature drops below the required heat to melt solder.

If you keep trying with your iron, you will soon destroy the socket, board
and PCB pads- the job must be done quickly with a hot iron. I have
replaced
several laptop power connectors and feel that a cheap hobbyist's iron in
the majority of cases would be quite inadequate.

I agree. When I said earlier that 30 watts is plenty, I hadn't quite
realized he was wanting to remove something with a substantial amount of
metal that needs heating up.

"mc" wrote in message
...
If you can borrow a temperature controlled iron, preferably one in the
45-50watt region, with a fairly broad tip, you should be able to do the
job
fairly easily.

What is happening is the large area of the multilayer PCB, combined with
the
rather large track area, is siphoning away the heat from the tip and
chilling it. The iron is not temperature controlled so cannot compensate,
so its temperature drops below the required heat to melt solder.

If you keep trying with your iron, you will soon destroy the socket,
board
and PCB pads- the job must be done quickly with a hot iron. I have
replaced
several laptop power connectors and feel that a cheap hobbyist's iron in
the majority of cases would be quite inadequate.

I agree. When I said earlier that 30 watts is plenty, I hadn't quite
realized he was wanting to remove something with a substantial amount of
metal that needs heating up.


I've had success doing what you want to by using the largest iorn I can find
and working really fast so that you don't destroy the board. I'd immagine a
45 - 50 Watt iorn would work well. Just don't leave the iorn on the board
more than a few seconds, just long enough to liquify the solder and add some
more. You will cook those solder pads if you use too small of an iorn or
take too long with a big one!

Mike

In article ,
"mc" wrote:

If you can borrow a temperature controlled iron, preferably one in the
45-50watt region, with a fairly broad tip, you should be able to do the
job
fairly easily.

What is happening is the large area of the multilayer PCB, combined with
the
rather large track area, is siphoning away the heat from the tip and
chilling it. The iron is not temperature controlled so cannot compensate,
so its temperature drops below the required heat to melt solder.

If you keep trying with your iron, you will soon destroy the socket, board
and PCB pads- the job must be done quickly with a hot iron. I have
replaced
several laptop power connectors and feel that a cheap hobbyist's iron in
the majority of cases would be quite inadequate.

I agree. When I said earlier that 30 watts is plenty, I hadn't quite
realized he was wanting to remove something with a substantial amount of
metal that needs heating up.

OP: Again - Before you invest $100 or more in a quality iron - which I
highly recommend - beg, borrow, buy or steal a couple of ounces of
liquid flux. A drop or two will make a world of difference in your
ability to reflow the old solder. Trust me on this one. You might just
be able to get by with the light duty iron if you use flux, and you'll
need it anyway even if you buy the better iron. And don't use the point
of the tip. Choke up on it a bit, where there's more thermal mass.

In article , "Michael Kennedy" wrote:

"mc" wrote in message
.. .
If you can borrow a temperature controlled iron, preferably one in the
45-50watt region, with a fairly broad tip, you should be able to do the
job
fairly easily.

What is happening is the large area of the multilayer PCB, combined with
the
rather large track area, is siphoning away the heat from the tip and
chilling it. The iron is not temperature controlled so cannot compensate,
so its temperature drops below the required heat to melt solder.

If you keep trying with your iron, you will soon destroy the socket,
board
and PCB pads- the job must be done quickly with a hot iron. I have
replaced
several laptop power connectors and feel that a cheap hobbyist's iron in
the majority of cases would be quite inadequate.

I agree. When I said earlier that 30 watts is plenty, I hadn't quite
realized he was wanting to remove something with a substantial amount of
metal that needs heating up.


I've had success doing what you want to by using the largest iorn I can find
and working really fast so that you don't destroy the board. I'd immagine a
45 - 50 Watt iorn would work well. Just don't leave the iorn on the board
more than a few seconds, just long enough to liquify the solder and add some
more. You will cook those solder pads if you use too small of an iorn or
take too long with a big one!

After working with the Weller rework station, all the other irons seem
way to large for the hand. The Weller being smaller in size is not small
on watts. 80 watts. Pleasure to work with.When I need big watts, i get
out the 250 watt Radio Shack gun.


greg

Morse wrote:

Antony,

If you can borrow a temperature controlled iron, preferably one in the
45-50watt region, with a fairly broad tip, you should be able to do the job
fairly easily.

What is happening is the large area of the multilayer PCB, combined with the
rather large track area, is siphoning away the heat from the tip and
chilling it. The iron is not temperature controlled so cannot compensate,
so its temperature drops below the required heat to melt solder.

If you keep trying with your iron, you will soon destroy the socket, board
and PCB pads- the job must be done quickly with a hot iron. I have replaced
several laptop power connectors and feel that a cheap hobbyist's iron in
the majority of cases would be quite inadequate.

Try eBay- I've seen old Weller magnastat soldering stations for about 15
UKP. Usually tatty to look at but they do a great job. I still use one
myself! The temperature is set by tip selection, and there's not much they
can't do with a hot tip fitted. Alternatively there's occasionally Antex
stations with user-variable temperature dials which go for a reasonable
amount. If you intend on servicing your own stuff you really need a
temperature controlled iron.


Those thermostaic irons were banned from production work, around
anything that's ESD sensitive.


Soldering guns are OK for the appropriate job but not really for PCB use
because they can only administer very high heat for short bursts and need
cooling off time before they can be operated again.


Another tool not allowed in a ESD sensitive setting.


To answer your question- exceeding the time will burn out the transformer
inside! The one I once used went off with quite a loud pop!

Morse


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

Smitty Two wrote:

OP: Again - Before you invest $100 or more in a quality iron - which I
highly recommend - beg, borrow, buy or steal a couple of ounces of
liquid flux. A drop or two will make a world of difference in your
ability to reflow the old solder. Trust me on this one. You might just
be able to get by with the light duty iron if you use flux, and you'll
need it anyway even if you buy the better iron. And don't use the point
of the tip. Choke up on it a bit, where there's more thermal mass.


LIQUID ROSIN FLUX ONLY!!!!!!!!!! Stay away from Ruby flux, or other
liquid acid fluxes, unless you want to destroy the computer.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida