Soldering iron problems

[Michael A. Terrell]

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?ModuleNo=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?ModuleNo=45545&&source=14&doy=13m6 ?

All advice appreciated.

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?

Antony

http://www.edsyn.com/main.asp?inc=view_product&id=201 Is what we
used on every bench that did any soldering at Microdyne. I had three,
with different tips. They are 70 watt, with adjustable, built in
temperature regulation.


--
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

 

[Michael A. Terrell]

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

 

[Michael A. Terrell]

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

 

[BH]

Mass of the tip, correct?- Hide quoted text -

- Show quoted text -

Correct

 

[Chris Jones]

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?ModuleNo=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?ModuleNo=45545&&source=14&doy=13m6 ?

Yes and No:
Yes the one you bought looks like it is crap, but no that particular Antex
one also looks pretty bad.

I suggest that if you want to buy an Antex iron for general use then the
tyle C, CS, XS etc are better than the one you listed above, though all are
fairly low powered. See how the bit surrounds the element on the better
Antex ones, whereas the worse ones look like a screwdriver tip that is
inserted into a hole in the element. For your job probably none of these
are powerful enough anyway.

They also do a temperature controlled version (all built into the handle),
look for BA14Q on Maplin. Because the temperature control will prevent it
from overheating, they can increase the heater power to 50W, which is
better. That iron might have enough power for what you want.

None of these irons will be very good on a multi-layer laptop board unless
you are quite lucky / well practiced. You really want a Metcal MX500 but
that is expensive.

In any case you can get some old scrap circuit boards of similar
construction, and practice on those until you are confident.

Chris