1. #1
    Thought I'd share in case it helps anyone in future.

    My Chinese 6040z died during a v bit carving. Gutted.
    Quickly established that the 24v power supply was dead.

    I opened it up and started checking things. Fuse had blown, indicating fault was in high voltage side. Long story short...

    Bridge rectifier partially shorted out, taking a power transistor and fuse with it. I always replace PWM Controller when power transistors have blown, just to be sure.

    The diode bridge, PWM and Transistors were all Chinese clones of already cheap parts. I replaced them with more trustworthy original parts. The PWM got a slight upgrade as well.

    Click image for larger version. 

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    Diode Bridge: KBU808 (8A/800v), replaced with genuine KBU1010 (10A/1000V)

    Power Transistors: clones replaced with genuine FJA13009TU

    PWM: cloned KA7500B Replaced with genuine KA7500C. The newer C version is more accurate and stable and a direct drop in replacement.

    Schottky Diode: This diode was okay, but I included it as it is a likely failure point. It's running close to the supposed spec and as it's a Chinese brand, it's on probation. I would have replaced it, but didn't have a suitable part handy.

    Total cost of parts 4.(6)

    Anyway- it's running fine now. Steppers sound more even toned when parked and power supply actually runs a fair bit cooler now.

    Hope it helps someone.

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  3. #2
    Replaced partsClick image for larger version. 

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  5. #3
    Thanks for talking the time to post the fixing procedure and the parts you use.
    Last edited by Nickhofen; 31-12-2017 at 08:21 AM.

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