Weller Station WTCP51 not heating..help please

Thread Starter


Joined Mar 22, 2009
Hi all,

I'm a newbie (so take it easy on me).
A friend loaned me his WTCP51 for doing some soldering..and after I successfully managed to solder 8 cables to a PCB, it suddenly stopped heating.
I changed the tip (no luck).
I left the station off for 30 min then on again..no luck.
It's not heating anymore.

Any idea what might be the problem and what could be the fix ?

I no longer hear the sound that the unit made when it was heated up and ok (I think there was something magnetically related)

Thanks in advance,
Last edited:


Joined Apr 20, 2004
Mine (40 years old now) has a habit of doing the same thing. There is enough oxidation in the barrel that the switch contacts can't move freely.

The tip is a magnet, and controls heating by pulling the switch in the barrel closed. At the setpoint temperature, it loses magnetism due to Curie effect, and opens the switch.

I mostly tap mine on the holder collar to get it going. The "real cure" is to unscrew the collar and remove the barrel to expose the innards and clean things up. Things are pretty tight in there...

Thread Starter


Joined Mar 22, 2009
Hi both,


Thanks for the link.
I was hoping though not to change anything yet..and also not deliver a broken station back to my friend.

Thanks "beenthere" for the explanation.
I undid the collar/unscrewed it..and found that underneath it, there's a rectangular tiny transparent plastic box with some metal plates which under the influence of the tip or a magnetic field open/close a circuit.
Those are the parts no longer triggering anything I'm afraid (I don't hear them move)
Did you mean cleaning those very small metal plates ? (it really seems like a pain in the *** to reach them and 2 very very small screws on the plastic box)
Like magic, according to what you said..I just shook a bit the soldering tool against the conical / spire support I use to place it in and it started warming up.
Now it works.
I'm still puzzled a bit.
Can you take me out of the dark ? :)

P.S. Thanks again..you saved me


Joined Apr 20, 2004
Can't really help beyond that - it's a matter of realizing that further investigation might cause more harm. So I just tap the iron now and again and it works fine.


Joined Jul 17, 2007
I also have an ancient W-TCP iron who's heating element gave up the proverbial ghost.
It was used in a production environment for years, but finally the heating element (a very fine Nichrome wire coated with an unknown ceramic-like insulating substance) burned through.

I'm glad you got it going. Replacing parts in those are a pain.

Thread Starter


Joined Mar 22, 2009
I'm also glad to have it going again.
I thought the day had just become a nightmare when it stopped functioning.

Thanks to both of you.
You really made my day good again.


Joined Sep 12, 2008
That may explain the strange phenomenon that i experienced with my iron.

I have a small Weller station as well, and when i replaced my tip with a tip from my dad (probably for a different iron) i turned the iron on, and let it heat up...

when i grabbed it to solder with it, the tip and barrel were glowing red, almost orange. (which is obviously too hot to solder with lol)

so i let it cool, replaced the tip again with another one, when i did, it was stuck in place. eventually it freed up and it works fine now with the new new tip.

I was going to trash it thinking that it was messed up and may cause a fire, but then again, i dont only shut the iron off before i leave the bench-I also wait until the tip returns to room temp. ;)


Joined Apr 5, 2008

I think the tip of the other iron was without a magnet.
This way the iron can not regulate the temperature.
The number on the magnet based tip is a mark for the temperature range.
I use most times number 7.



Joined Apr 6, 2009
See this post (from the usenet archive) for technical details about the Weller magnetic-switch irons: (WTCPS, etc)

Also, let me share a bit of advice for replacing old heaters in these irons. (I called Weller today to clarify this because it was confusing me.) The heater (part number EC234) underwent a design change in 2000 or so. There are 2 versions of the EC234, but they carry the same part number. Old heaters are straight cylinders. New heaters have a slight "bump" from the base to a larger cylinder size further up the shaft. You can see this in the product photos here:

The new heaters require an updated barrel nut assembly (part BA60) with a larger internal diameter. These were introduced in 1998, also without a part number change.

So... if you're replacing an old (straight-cylinder) EC234 heater, buy a new BA60 to go with it. Otherwise, you will find yourself (like me) with a shiny new heater and no way to install it.

Weller said that all BA60s and EC234s currently on the market are the new styles, and a new BA60 will fit over an old EC234 without problems.

Hope it helps somebody.