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Invertec V140-S, need PWM circuit and resistor R48 value

20 Sep 2016 22:58 1716 2
  • Level 8  
    Hi dear technicians. Does anyone have a wiring/circuit diagram of PWM module at Invertec V140-S? Sеveral weeks ago i receive this inverter with completely burnt out power module - six IGBT's (HGTP12N60) and two diodes (STTH12R06) has destroyed. Now I has finish with recover them and the gate pulses are correct, but ... When try to ignite arc the welding current is extremely high (around 150...155 A!) and no output current control from potentiometer. The potentiometer, output current sensor (shunt) and 8-wire cable between front control board and inverter board are correct. Something in PWM module make me crazy. In first place the device has previous attempts to repair from someone else and I'm not 100% sure in IC component type and placing: U1=LM324N, U2=LM393N, U3=TDA1060, U4=LM324N and U5=LM358N. That's correct? And second - the original resistor (R48) in red circle position is completely crumbles to pieces from rust and colour code are missing. I try to measure his remains and got as result around 220k. Also replaced, but again no 100% sure in this value! The IC's nr. 1, 2, 4 and 5 has also replaced (easy, adaptor socket), but no difference in problem status. The diodes and transistors in module is measured too and not damaged. I suspect R48 is with incorrect value, but no circuit diagram of PWM module. Does anyone have any high resolution photo of this PWM module or schematic diagram with component values?
    Invertec V140-S, need PWM circuit and resistor R48 value

    This is the device:
    Invertec V140-S, need PWM circuit and resistor R48 value
    PS: I have service manual, but there is no PWM/control circuit diagram with component values.
    Thank's in advance!
  • Level 8  
    No gustlik666, the IC1 in my case is not correct! There is LM324, replaced wrongly from previous people! The original integrated circuit at that place is LM339! After some my investigation from pinouts, I revealed it. ..And late i saw the board layout from romanian site and yes - i was right.