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Weller Soldering station EC2100M

Discussion in 'Electronic Repair' started by radio10, Sep 15, 2012.

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  1. radio10

    radio10 Guest

    I have my son's Weller EC2100M unit on my bench to take look at.

    This is the one where the iron does not have the magnastat thingy and it is the
    Station that digitally displays temperature and the operator adjusts the
    temperapture from a knob on the front.

    However, the temperature will not adjust. Upon switch on the unit displays the
    rising temperature which stops at 550C. At this point the iron tip is red hot!

    I was dismayed to find a largish microprocessor inside (4 MHz clock crystal
    operating ok) along with another programmable 8 pin chip plus an op-amp a triac
    and 5 volt reg. All surface mount:-(

    The regulator and triac check out ok.

    Anyone got this unit and had any experience like this?
  2. N_Cook

    N_Cook Guest

    Broken wire in the lead to the temp sensor/thermocouple ?
  3. Phil Allison

    Phil Allison Guest


    ** Yep - and it was always a faulty iron.

    Either terminations on the cable or the temp sensor has died.

    Spare heater elements and irons are normally available.

    ..... Phil
  4. Jamie

    Jamie Guest

    550C is just over 1000F, that's hot, and if the iron isn't shutting
    down, then you have a switch problem with in the triac circuit..

    I'll give you some insight with triac's, sometimes one half inside
    shorts out and you'll get 59% duty to the iron and it won't show on a
    diode test.

    Disconnect the gate to the triac and tie it off to prevent it from
    triggering.. See if the iron still heats. If so, replace the triac.

    If it deos not heat, then walk you're way back in the gate circuit and
    look for something that looks like optical coupler. This maybe a 6 pin
    or 4 pin chip and it could be yellow packaged and some times black.
    using an ohm meter, check to make sure the coupler isn't shorted on the
    output. if that passes.. Then check for the presents of a pulse on the
    input side of the coupler.

    One other item you want to check and that is the possible use of a
    snubber cap network around the triace, they some times short. I've seen
    poor designs use MOV's for this.

    There is also the possibility the triac is connecting the common side
    to the wand and the wand has shorted against the common. That would be
    the heater element lead wires.. You can check that with a ohm meter too.

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