Weller WTCP-N problem: No Heat

[Ian]

My weller soldering station failed yesterday for the first time in
years. I am not getting any heat. I would get the heater is out but is
there a way to confirm what the problem is so I can try and track down
some parts.

Looking at the soldering pencil apart on my desk, which part is the
heater and which part is the temperautre switch? I am guessing that
the barrel is the heater element but I am really not sure.

Take Care all.

 

[Ray L. Volts]

My weller soldering station failed yesterday for the first time in
years. I am not getting any heat. I would get the heater is out but is
there a way to confirm what the problem is so I can try and track down
some parts.

Looking at the soldering pencil apart on my desk, which part is the
heater and which part is the temperautre switch? I am guessing that
the barrel is the heater element but I am really not sure.

Take Care all.

The N model should be similar to my WTCPS, which appears to be essentially
the same as the new WTCPT on the Weller site. To get the exploded diagram
of the WTCPT, go to

http://www.cooperhandtools.com/brands/weller/index.cfm

and search for "wtcp". Click the WTCPT station link and from the list
select WTCPT_OI_PL.pdf

 

[Eric]

I have a Weller solder iron and has similar problem end up with bad surface
mount electrolytic capacitors.

Good luck

Eric

 

[Jim Adney]

My weller soldering station failed yesterday for the first time in
years. I am not getting any heat. I would get the heater is out but is
there a way to confirm what the problem is so I can try and track down
some parts.

Things to check:

Make sure that you're getting 24VAC out of the base. Some of these
have a fuse inside.

Make sure there are no broken wires in the cord (very common.)

Looking at the soldering pencil apart on my desk, which part is the
heater and which part is the temperautre switch? I am guessing that
the barrel is the heater element but I am really not sure.

The heater is in the barrel, while the switch is back inside the
handle. You should be able to figure out the source of the problem
with an Ohmmeter.

These are excellent units, well worth fixing.

-

 

[Isaac Wingfield]

Things to check:

Make sure that you're getting 24VAC out of the base. Some of these
have a fuse inside.

Make sure there are no broken wires in the cord (very common.)


The heater is in the barrel, while the switch is back inside the
handle. You should be able to figure out the source of the problem
with an Ohmmeter.

These are excellent units, well worth fixing.

A common problem is that the contacts in the switch get oxidized. It's
possible to take the switch apart and clean the contacts with very fine
emery paper or crocus cloth.

The operation of the temperature control is by means of the Curie
effect. The heater switch is held closed by magnetism until the
temperature reaches the set point (determined by the alloy that the tip
insert is made from -- the number on the base multiplied by a hundred is
the setpoint). At the set point, the tip insert becomes non-magnetic,
and a spring pops the contacts open. When the tip cools down, the
magnetism returns, and the switch is pulled closed again.

Isaac

 

[Jim Adney]

A common problem is that the contacts in the switch get oxidized. It's
possible to take the switch apart and clean the contacts with very fine
emery paper or crocus cloth.

I'd recommend a very mild points file rather than an abrasive, because
abrasive can get left behind, embedded in the contact material, and
it's an insulator. Whatever you use, however, I agree that you need to
be very careful not to be too aggressive.

The operation of the temperature control is by means of the Curie
effect. The heater switch is held closed by magnetism until the
temperature reaches the set point (determined by the alloy that the tip
insert is made from -- the number on the base multiplied by a hundred is
the setpoint). At the set point, the tip insert becomes non-magnetic,
and a spring pops the contacts open. When the tip cools down, the
magnetism returns, and the switch is pulled closed again.

Yes, exactly. A very cool system. ;-)

-

 

[tom_mc_h]

My weller soldering station failed yesterday for the first time in
years. I am not getting any heat. I would get the heater is out but is
there a way to confirm what the problem is so I can try and track down
some parts.

Looking at the soldering pencil apart on my desk, which part is the
heater and which part is the temperautre switch? I am guessing that
the barrel is the heater element but I am really not sure.

Take Care all.

Assuming that the 24 volts is ok from the base - and the connector is
doing its job - I often cure the no heat problem by removing the
sleeve and pulling the tip (cool of course) in and out several times.
You should be able to feel the switch actuate in the handle and that
little bit of exercise usually gets the switch working again.

 

[Woody]

[email protected] (Ian) wrote in message

Usual fault is that the inside of the barrel has got rusty and the
magnetostat is stuck or can't move. Take the sleeve off, remove the bit, and
push a screwdriver into the tube and give the 'stat shaft a few good
wellyings. Usually cures it great.

Unless it is very old and decrepit it is unlikely to be the switch although
it is not unknown.

 

[Isaac Wingfield]

I'd recommend a very mild points file rather than an abrasive, because
abrasive can get left behind, embedded in the contact material, and
it's an insulator. Whatever you use, however, I agree that you need to
be very careful not to be too aggressive.

Crocus cloth is explicitly recommended for cleaning motor commutators,
so it should be fine -- actually, it's *very* fine 8^}

Some abrasives are insulators, and some are conductors; carborundum is a
conductor, for example. If I need a bit more "aggression" than crocus
cloth provides, I use a 600 grit carborundum "wet or dry" paper; the
grit is very solidly attached. A file, even a fine one, will remove a
lot more material than an abrasive.

Isaac

 

[Jim Adney]

Crocus cloth is explicitly recommended for cleaning motor commutators,
so it should be fine -- actually, it's *very* fine 8^}

Yes, I agree, it's very fine. As long as it doesn't leave anything
behind it should be fine.

Some abrasives are insulators, and some are conductors; carborundum is a
conductor, for example. If I need a bit more "aggression" than crocus
cloth provides, I use a 600 grit carborundum "wet or dry" paper; the
grit is very solidly attached. A file, even a fine one, will remove a
lot more material than an abrasive.

I really don't think carborundum is a conductor. Can you find support
for this statement anywhere?

I agree about the file. A more proper tool would be a burnisher.
Contact burnishers just look like a thin flexible steel leaf with a
matte finish which is very slightly abrasive. They're sold for this
purpose, but I don't know if you can still buy them anywhere. I hear
they were fairly common in the old days when IBM accounting machines
consisted of banks of relays which were actually expected to be
serviced.

-

 

[Isaac Wingfield]

Yes, I agree, it's very fine. As long as it doesn't leave anything
behind it should be fine.


I really don't think carborundum is a conductor. Can you find support
for this statement anywhere?

I was speaking from a memory of having used carborundum power resistors
years ago in FM broadcast transmitters; they were small for their power
rating because they could operate at a very high temperature without
much resistance change.

I found one mention of 1000 ohm-cm. at 1000 degrees C.

Here's an interesting URL I ran across:

http://home.luna.nl/~arjan-muil/radio/carborundum.html

Isaac

 

[Jim Adney]

I was speaking from a memory of having used carborundum power resistors
years ago in FM broadcast transmitters; they were small for their power
rating because they could operate at a very high temperature without
much resistance change.

Now that you mention it, we use carborundum power resistors quite a
bit where I work. I probably have quite a few of them in my current
project. I'm still not sure that this is something we'd want caught in
our relay contacts, however.

I'm not actually sure what serves as the resistive material in a
carborundum resistor. Is it the carborundum itself?

I found one mention of 1000 ohm-cm. at 1000 degrees C.

Not quite what I had in mind for my relays either. At 1000 C, I
suspect that many things become more conductive.

Here's an interesting URL I ran across:

http://home.luna.nl/~arjan-muil/radio/carborundum.html

Thanks, I'll check it out.

-

 

[Jim Adney]

I checked with some other people at work and they pointed out that SiC
is actually a bit of a semiconductor, so it is somewhat conductive and
that's why it can be made into a resistor. No one knew what the
resistor people do to it to vary the resistivity, however.

The semiconductor people are working with it to see if they can make
power semis from SiC that will operate happily at 400 C. If they
succeed, it will be a lot easier to "cool" something that is still
happy at that temp.

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