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    Default QT 18 no start

    I have a 1994 mazak qt18 with a tplus control. I went to start it today and nothing happens. i hear the fans turn on when you turn the main switch on. However, when the Green start button is pressed, nothing happens. (the green button is illuminated) I had someone push the green start button while i was in the back electrical cabinet and i hear something clicking in the MITSUBISHI NC Power Supply QX084 and a red led flashes ( red circle in picture) . I have replaced the 2 - 24v power supplies shown in a blue circle and just checked and they appear ok. Does anyone know if i should focus on the NC power supply? anything to check w/ the meter?

    on a normal startup i hear the main breaker trip, then the hydrualic pump.


    ps.jpg

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    Quote Originally Posted by simonswb6 View Post
    I have a 1994 mazak qt18 with a tplus control. I went to start it today and nothing happens. i hear the fans turn on when you turn the main switch on. However, when the Green start button is pressed, nothing happens. (the green button is illuminated) I had someone push the green start button while i was in the back electrical cabinet and i hear something clicking in the MITSUBISHI NC Power Supply QX084 and a red led flashes ( red circle in picture) . I have replaced the 2 - 24v power supplies shown in a blue circle and just checked and they appear ok. Does anyone know if i should focus on the NC power supply? anything to check w/ the meter?

    on a normal startup i hear the main breaker trip, then the hydrualic pump.


    ps.jpg
    update
    i pulled the nc power supply, notice the 2 caps that bled and burned out the other components... im not sure if this is the only problem but maybe part of the problem.

    bled.jpg
    20191006_062558.jpg

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    Quote Originally Posted by simonswb6 View Post
    update
    i pulled the nc power supply, notice the 2 caps that bled and burned out the other components... im not sure if this is the only problem but maybe part of the problem.

    bled.jpg
    20191006_062558.jpg
    Replace capacitors, the same goes for burned components (I see a diode and two small SMT capacitors near electrolytic caps- change these too, as electrolyte leakage do a damage both to components and PCB traces). Also suggest to check voltage stabilizer ICs (mounted on heatsink)on that line where bad caps are located. These components aren't expensive.

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    Yes, the power supply is the most-common failure point of the T/M-Plus NC control unit.

    Check Ebay for good prices on a spare....

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    The backup battery for the programs and parameters etc is on the P.S.
    If it is unplugged overnight, you probably will need to re-initialize the control, and replace the items lost.

    Bill

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