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Weller WTCPN Problems

Discussion in 'Electronic Design' started by Tim Wescott, Jan 25, 2005.

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  1. Tim Wescott

    Tim Wescott Guest

    Anyone have any experience with the Weller WTCPN soldering station and
    TC201 iron? I just blew the fuse in the station -- other than chucking
    the tip, is there anything else I need to do? Am I screwed?

    Where's the actual heating element in these? I assume the switch is in
    the tip.

  2. 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_.
  3. I bet it's either a bad fuse or a bad heater. New heater is around
    fifteen bucks US, no big deal.
  4. Ross Herbert

    Ross Herbert Guest

    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.
  5. Tim Wescott

    Tim Wescott Guest

    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?
  6. Tim Wescott

    Tim Wescott Guest

    Is that how it works? Cleva.

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

    Joerg Guest

    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
  8. 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.

    John Crighton
  9. Bill Bailley

    Bill Bailley Guest

    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.

  10. Tim Wescott

    Tim Wescott Guest

    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.
  11. Hello Bill,
    that is a good idea! Thanks for that tip.
    John Crighton
  12. Guy Macon

    Guy Macon Guest

    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
  13. Bill Bailley

    Bill Bailley Guest

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

  14. Tim Wescott

    Tim Wescott Guest

    Nope. I checked after reading your other post.
  15. Tim Wescott

    Tim Wescott Guest

    It's the temperature control switch inside the pencil handle that I need.
  16. 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 ;)
  17. Tim Wescott

    Tim Wescott Guest

    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.
  18. Rich Grise

    Rich Grise Guest

    Before you do anything drastic, does the fuse _not_ blow when the cord is
    unplugged from the base? That would eliminate some hidden problem in the

    Good Luck!
  19. Guy Macon

    Guy Macon Guest

    ....unless you buy the model with the temperature control and the
    digital display. No switch in the handle to go bad, just a
    temperature sensor. Of course itvwouldn't be a WTCPN. It would be
    a WSD81

    BTW, an new switch costs $32.29 here:
    or $28.82 here:

    While looking for the switch, I ran across these gems:

    Self Contained Air
    WTA50 Thermal Tweezers
    DSV80 De-Solder Pencil-De-Solder Tips
    WSP80 Soldering Pencil - Solder Tips
    HAP1 Hot Air Pencil
    Digital-Microprocessor Controlled
    List: $2,399.00

    WHP3000 Digital Preheating Plate, 600 W, 120V
    Enables electronic assemblies to be preheated from the bottom
    The unit slides easily below the WBH3000S PCB holder
    The heating plate heats up the component from below to the correct temp.
    Equipped with 3 infrared lamps for fast and accurate heat-up
    Precise temperature control is achieved with the digital electronics
    The unit is equipped with Auto-Off and Standby features
    Read and set temperatures are indicated digitally
    A RS 232 interface allows control by the WHA3000P Hot Air Station
    Temperature can be regulated with the use of an optional external sensor

    If anyone here wishes to buy me a Christmas present...
  20. Richard H.

    Richard H. Guest

    I've been watching this system for years, and finally had a good reason
    to get one. I imagine it also makes a very nice gift... :)
    Air pencil:
    Air pre-heater:
    Supplies (2000 kit):
    Board holder:
    Pick tool: - handy for 0402 chip caps

    It produces great results, and it's kinder on the parts than the toaster
    oven method, especially if you add parts incrementally in a proto (or
    mount your decoupling caps on the bottom). The pre-heater makes a
    *world* of difference when soldering SMT pads on a ground plane.

    Check eBay. They're seldom listed, but you could probably get the whole
    system for $500.
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