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    Weller TCP-01 soldering iron question / problem with thermal switch

    Hello
    I have a Weller base station with TCP-01 hand piece. (very common)

    it was working for years and it always used to make clicking sounds as the thermal / magnetic switch opened and closed.

    Then the switch went faulty and I purchased a new one for $$$.

    I fitted it and the iron does get hot but I do not ever hear or feel any clicking.


    I asked the supplier but they do not know and offered that I can return the switch.


    So the question is, is the new switch faulty or is one not supposed to hear / feel the clicking?


    Best regards
    X

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    Re: Weller TCP-01 soldering iron question / problem with thermal switch

    Hi,

    Afaik, you can have the tip for different temperatures.
    Thus you can use a thermometer and check the tip tempeeature.

    I assume - when there is a fault - then the tip temperature is much higher than expected.

    Klaus
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    Re: Weller TCP-01 soldering iron question / problem with thermal switch

    If the switch sticks the iron will visibly glow red hot so if it seems to work as normal it should be OK.
    I modified one years ago when the switch broke by polishing the contacts and using them at lower current to trigger a small triac. Kept it working for years afterwards.

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    Re: Weller TCP-01 soldering iron question / problem with thermal switch

    A very long time ago I built a circuit into the transformer box for such a soldering pen (on the secondary 24V AC side), so a LED indicated when power was used.
    For testing, you can simply measure the AC current on either the primary or secondary side of the transformer with a multimeter.
    If I remember correctly, my pen reached 370C in less than 1 minute.
    If your pen draws current constantly for 5 minutes, something is probably broken.

    Also, the pen should not get hot if you apply power when the tip is removed.

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    Re: Weller TCP-01 soldering iron question / problem with thermal switch

    Interesting, I will measure it.

    It does not get red hot.
    The tip is same as before and it has a number 8 on the back
    The switch does only click when I insert and remove the tip (iron off).

    Yea, strange, my work's Weller with temperature knob does have a LED in the base station for indication.
    My old private one does not but then again, it is quite a bit older.

    BTW, the old switch failed in that it's wire rode from the magnet to the rear contact plate corroded through and eventually broke.

    Regards
    X

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    Re: Weller TCP-01 soldering iron question / problem with thermal switch

    Well your 8 indicates 410 degrees C :)
    I mainly use 7's in various shapes - 370 degrees C.
    NEVER operate this iron on DC. It destroys contacts in switch.
    Mine operates from 1981 with only one switch change.
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    Re: Weller TCP-01 soldering iron question / problem with thermal switch

    I followed your ideas and measured the current last night.
    The element draws around 1.8-1.9A~ when on/heating.
    Then it drops off to 0 and starts coming on and off correctly.

    All this, completely silent. I can't feel or hear any clicking.

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    Re: Weller TCP-01 soldering iron question / problem with thermal switch

    It is normal behaviour for Magnastat type of soldering irons (Weller patent).
    It does click and I can hear it on any Weller magnastat, only if the envoronment is quiet :)
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    Re: Weller TCP-01 soldering iron question / problem with thermal switch

    I've got a bunch of older Wellers and some are noisier than
    others; probably about acoustic coupling as-assembled than
    anything else.

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    Re: Weller TCP-01 soldering iron question / problem with thermal switch

    Worst of all, I still do not fully understand how it works.
    That is shocking, considering how long I have been using these irons!

    I opened the old switch and discovered the following:

    1) There is a wire rod in there, with a contact plate on one end and a piece of metal on the other end (I think that could be a magnet. I forgot now).
    2) The contact plate at the back shorts 2 contacts (or not) and is the actual switch part.
    3) There is a spring that pushes the rod assembly to the rear, away from the tip.
    4) When you put the tip in, the rear of the tip attracts the metal piece (or magnet) and pulls it, the rod and the contact plate towards the tip. This causes the contact plate to close the 2 contacts = ON.

    What I do not understand:
    1) What causes the contacts to open at the target temperature
    2) What the difference in the tips is (different numbers) in as far as changing the temperature and when that switch opens.

    Does anyone know perhaps?


    Regards
    X

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    Re: Weller TCP-01 soldering iron question / problem with thermal switch

    Quote Originally Posted by userx2 View Post
    Worst of all, I still do not fully understand how it works.
    That is shocking, considering how long I have been using these irons!

    I opened the old switch and discovered the following:

    1) There is a wire rod in there, with a contact plate on one end and a piece of metal on the other end (I think that could be a magnet. I forgot now).
    2) The contact plate at the back shorts 2 contacts (or not) and is the actual switch part.
    3) There is a spring that pushes the rod assembly to the rear, away from the tip.
    4) When you put the tip in, the rear of the tip attracts the metal piece (or magnet) and pulls it, the rod and the contact plate towards the tip. This causes the contact plate to close the 2 contacts = ON.

    What I do not understand:
    1) What causes the contacts to open at the target temperature
    2) What the difference in the tips is (different numbers) in as far as changing the temperature and when that switch opens.

    Does anyone know perhaps?


    Regards
    X
    I believe they regulate there temp by curie effect.

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