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  1. #1
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    Atten 850 b Soldering Station not working

    Hi everyone,
    I have my soldering station that have a problem.
    With knob Until 280 °c It does not heat up at all, but output only air.
    Moving the knob over this temperature begin to heat but not much.
    The heat led is always off, while the air led is always on.
    You have some idea for to start to solve this problem?
    Thank you
    Erchiu

    •   Alt21st November 2017, 13:13

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    Re: Atten 850 b Soldering Station not working

    Hi,

    * temperature sensor, or
    * input side of temperature error amplifier (both).

    Klaus
    Please don´t contact me via PM, because there is no time to response to them. Thank you.


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  3. #3
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    Re: Atten 850 b Soldering Station not working

    Hello erchiu,
    Check the two large high watt resistors, the white rectangular one and the green one.
    If either or both have gone high or open circuit, then replace them with 7 or 10 watt types.
    Ensure they both stand at least 15mm off the circuit board.
    It also wouldn't hurt to spray the heat control pot with CRC multi-purpose lubricant, just
    in case the wiper and tracks are dirty. Unlikely, but if you have any, its worth a try.
    There is also a slight possibility that the heating element inside the handle is faulty.
    The only way I know of to confirm this is to replace it.
    Regards,
    Relayer
    Last edited by Relayer; 22nd November 2017 at 03:46.


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    •   Alt22nd November 2017, 03:41

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    Re: Atten 850 b Soldering Station not working

    Hi everyone,
    I checked the big resistors. One is from 1 ohm and one from 1 kohm and both is ok.
    I checked the heater on gun handle and it its value is 86 ohm.(I think it is right)
    There are other 2 wire that i think the probe, but i don't know how to measure it.
    I tried for ohm but its open circuit.
    I trieid for mv but its value is zero.
    I believe it is a termocouple, but i don't know to measure it.
    Other suggestions.
    Erchiu
    Last edited by erchiu; 23rd November 2017 at 09:27.



    •   Alt23rd November 2017, 09:20

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    Re: Atten 850 b Soldering Station not working

    Hello erchiu,
    Which plug/s on the main board goes to the heater assembly?

    Can you please have a look at your modified picture below:



    Could you please check the fusible (safety) resistors shown by the red arrows.
    Can you please identify the component marked with the green arrow.
    Lastly, can you please provide a part number of the transistor or MOSFET marked with the blue arrow.
    Thank you.
    Regards,
    Relayer



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    Re: Atten 850 b Soldering Station not working

    Dear relayer,
    Thanks for your help.
    I maked other better pictures.
    I checked R26 and R27 both 56 kohm and are ok.
    I checked R23, 51 ohm and it's ok.
    The black component is a relais as you can see from the picture.
    The plug that go to heater gun is labelled with "RL" and it is has 4 wire (2 for heater e 2 for probe).
    The component with heatsink (Q2), unlabelled. I think that is been deleted in factory but i believe that is a triac because the heater go to 220 AC.
    Q3 is a Triac BTB04 600 A, while U2 is a voltage regulator 7812 CT.
    U8 is an TL431.
    Regards erchiu



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    Re: Atten 850 b Soldering Station not working

    Quote Originally Posted by erchiu View Post
    There are other 2 wire that i think the probe, but i don't know how to measure it.
    I tried for ohm but its open circuit.
    If the two other wires, beside the heating element, indeed is a thermocouple, open circuit means the sensor is broken. You should measure near 0 ohm on those.

    If you can reach the end of the thermocouple wires, you should see the ends joined in a welded dot. If they are open, you could weld them again, like in this video: https://www.youtube.com/watch?v=vAjZ5PdEM-k

    Good luck,
    Mike



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    Re: Atten 850 b Soldering Station not working

    Yes,
    now i sure that the soldering station use an thermocouple for temperature control.
    i measured its terminals near weld point and the circuit is open, but the weld seems right.
    maybe this weld have need be make again?
    how i can do it?
    I seen the video, but i haven't that welding machine.
    i have an electric welding from blacksmith, but i think that very big for this job?
    what do you think?



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    Re: Atten 850 b Soldering Station not working

    Are you sure the break is in the welded junction? Check connectivity for each lead from the leads at the junction to the pcb. Note that the leads near the junction are heavily oxidized and might need cleaning before your dvm probes can make contact.

    If it is in fact the welded junction that is bad, cut off the weld saving as much of the leads as possible, clean the leads carefully from oxide and dirt (with a file), then weld them with a 12V car battery, with this technique: https://www.youtube.com/watch?v=-8cBCjJJcB4

    I would suggest you practice on another pair of wires to get the technique right before you weld the thermocouple as you probably only have one shot at this.

    IMPORTANT: Make sure that the thermocouple wires are FAR from the heater and heater wires and that they cant possibly make contact! If they do, you probably ruin the unit, and worse, might lead to lethal electrical shock. Make sure the unit is properly grounded at all times.

    Make sure you don't short circuit you battery!
    Last edited by linux-dude; 9th December 2017 at 11:49.



    •   Alt9th December 2017, 11:34

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  10. #10
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    Re: Atten 850 b Soldering Station not working

    You are right,
    i cleaned the terminals near the weld point and now i have short-circuit.
    then the weld is good.
    After the weld point the wires gone to little ceramic (believe) tube,.
    Outside this tube one of these wires is broken.
    exactly the yellow wire.










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    Re: Atten 850 b Soldering Station not working

    Ok, then pull out all the wires out of the air hose and check the cables for any issues, and locate where it's broken. Note that intact insulation on all 4 wires is vital for both safety and proper function. You can not replace the thermocouple wires with copper wire, you have to either replace the entire thermocouple or find where it's broken and reconnect it. You might be able to reconnect with solder, but make sure that the wires have proper direct contact before soldering (your temp control might otherwise have an offset), i.e. clean the joining leads carefully, twist them together with pliers and then solder. Finish up with heat shrink tube to insulate properly. Also, make sure no sharp ends in your new joint can puncture your heat shrink tube.

    Before you reconnect it, check that the thermocouple and the heater wires have no contact with your dvm at Mohm tange.



  12. #12
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    Re: Atten 850 b Soldering Station not working

    hi everyone,
    after one month about is arrived the heat element with thermocouple sensor inside.
    i replaced it and now the solder rework station work good again.
    erchiu



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