Weller WTCPN Problems

The fuse is fine -- it did it's job. The base now has a natty fuse block with fuse #3 in it. It appears that the heater is, indeed, bad and I've ordered heating element #2. If I get time I'll dink with the heater element per Ross's comments, to see if I can get it going for the next few days.

Thanks guys. Sphero, if a heater doesn't fix it I'll whine at _you_, OK?

Is that how it works? Cleva.

But there's often a micro under the iron...

I bet it's either a bad fuse or a bad heater. New heater is around fifteen bucks US, no big deal.

Thanks everyone -- you've figured it out for me faster than I could have. The switch has gone belly up.

One more thing, though: who carries switches?

Thanks again.

"Tim Wescott" wrote

Is this the one with the magnetic tip? If so, there is not much that can go wrong.

Does it blow a new fuse? The base is just a transformer and on-off switch. I would ohm the transformer primary and secondary and the heater handle.

For the young-uns:

The handle contains heater and a magnetic switch. The tips have a slug in them. The slugs are made from various alloys that loose there magnetic properties at some temperature, this turns off the heater till the magnet cools down and again attracts the switch to turn the iron on. Tips come with different slugs with different curie temperatures. Not a uP to be seen _any where_.

Follow the advice from Nicholas just to be sure.

Depending on the country of manufacture for your base unit there may be an in-line fuse inside the case. I know there is on mine (Australian manufacture).

I would also suggest that you check the heater element to make sure that there is no connection between the element and the outer tube. When these get old the ceramic cement separating the element from the outer tube can break down thus resulting in a short circuit across the transformer secondary. I have seen this happen on one of mine.

Hi Tim,

You've got all the hints you needs. Like Spehro my first guess would be the heater element. Other than a short in the connector there isn't much more in these things that could trip the fuse.

If you ever think about a new one: I am very pleased with the adjustable version WECP. The simple one with just the temperature dial knob, the fancy ones with digital readout blew out on me too often and then it's always expensive. The WECP cuts down on the number of tips needed, no more #6, 7, 8. Less blisters, too. And it's handy for the new 'unleaded' stuff where temps need to be higher or when you can briefly crank it up to unsolder some big electrolytic.

Regards, Joerg

Certainly not. You can fix it. Unplug or disconnect the soldering pencil TC201 from the transformer. Check and test the transformer , 24V 2 amp. If it is dud, any old tramsformer around 22v to 26V capable of supplying at least 2 amps will be fine. Find a replacement transformer from your junk supply. Or power the iron TC201 from a suitable bench DC power supply if you are in a hurry to do some some sodering.

Check the TC201 soldering pencil/iron. Do a continuity check. 2 element wires and 1 earth wire. Look for low resistance. If open circuit all is not lost. There is a switch in series with the element.

Have a look here and you will see what I am talking about.

Look at the diagram and you will see the element and switch assembly. Undo the three screws that form a triangle and separate the metalwork from the plastic handle. The fourth screw holds a small bracket. You can loosen that one later.

When you open it up you will see the heating element and a sealed magnetic switch assembly held by a spring resting on the small bracket.

Be very careful how you handle the fragile wires going to the heating element. They break off easily and then you will be kicking yourself when you find out the price of a replacement element.

The switch should be closed, so check it with your ohm meter. If the switch is dodgy and you just want to make a temporary repair you can carefully drill and cut away some plastic to expose the switch contacts and then clean them. Use one of your soldering iron tips to check the action of the switch. You will feel the magnetism and here a click. Use your ohm meter on th eswitch contacts.

You will find the fault easily.

Regards, John Crighton Sydney

Hello Bill, that is a good idea! Thanks for that tip. Regards, John Crighton Sydney

Here is what i would do;

The people who do extreme case modifications often use aircraft switches that require you to flip back a cover; this gives them that "serious hardware" look. If my soldering iron switch ever goes bad, I will put one of those in just because it's cool.

Then again, I have two outlet strips on my test bench; one for things that stay on 24/7 and one for things that I turn off when I leave. Outlet strips are a lot easier to replace than OEM switches.

Nope. I checked after reading your other post.

It's the temperature control switch inside the pencil handle that I need.

At the point that I realized I had spent enough time to buy 1-1/2 handles I stopped and ordered a handle -- but I'll try sanding the contacts when I get into a slack period, and enjoy my nice new handle in the mean time!

I suspect that something touched that shouldn't and took out the switch and fuse both. The thing was used when I got it over 10 years ago and I've been using it off and on since then, so it's not surprising that odd things should happen.

I have owned the same iron for quite a few years now. I got quite fed up with fairly constant replacements of the switch assy. Those contacts are switching 2 amps many times in a working day and burn out on a regular basis. While you are fixing it, you may want to consider a small modification which will give the switch a very long life.

Some years ago I rewired the pencil so that the switch controlled a GP triac mounted in the base assembly. For safety reasons, the triac is controlling the 24vac feeding the pencil. A small heat sink was required and, from memory, the element was getting about 21 volts. I did think of doing something better with a bridge/FET/filter cap arrangement, but I am reluctant to "improve" something that has worked flawlessly for 4+ years.

Bill.

Google for WTCP switch or something. While waiting for the new one, you could take the plastic cover off and sand the contacts, if that's the problem.

I still don't understand why the fuse blew... if the switch hangs, the iron just get bloody hot and even hotter than that. I know, because that happens after sanding the contacts for the second time ;)

"> Thanks everyone -- you've figured it out for me faster than I could

Tim, You may find that the switch that will no longer deal with 2 amps, will deal nicely with the few milliamps required to trigger a triac. The switch in my pencil fell into that category, and is still working well today. A quick check with the multimeter will give you some idea if this applies to your switch.

Luck, Bill.

Now how do we solder up this Triac circuit with a dead Soldering Iron !!

Yukio YANO

Seriously, Do you use the original cord ?, I can't visualize how you could do that without compromising the green grounding lead , As I recall, there are only three wires in the factory Cable, and three pins in the connector!.

I just love the mental picture of having yiur soldering iron apart and needing to solder a connection inside of it. Sort of like soldering 32 XLR connectors to the end of an audio snake and then realizing that you didn't slip the parrels over the wires first.

I did use the original cord, and as far as I remember I kept the barrel of the pencil at ground potential. It is quite while back now but I remember having some anxieties over grounding issues. I must have resolved them to my satisfaction, so I am fairly sure this design group can do a similar or better job. The station and pencil are quite a few thousand clicks away, and I am not quite done with my holiday yet. It seems as though you may have to re-visit that problem.

I did make an ass of myself when I came to wire my creation together and reached for the soldering iron. oops!!!

Added:- From the dregs of my shaky old memory I recall a 680R for the trigger and a daisy chain of 3 x 33K for the ground link.

Bill.