Question about MXR Phase 90 Pedal

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How do I fix a mxr phase 90 (overvoltaged!with 12V universal)

I just would like to know, how do I fix a mxr phase 90 which went dead after I overvoltage it with a 12V power supply(it's a non-regulated power supply, I accidentally push the switch to 12!).
i've done some googling, and found the schematic but still don't really get it. your help is really much appreciated.

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  • leybakqeed Apr 30, 2010

    lol, looking at these

    looks like something is fried. btw, do you happen to know the part name for that input thing?

  • leybakqeed Apr 30, 2010

    cant i just use a pen-multitester?when i checked it using my pen-multitester, it appears everything is working, i mean the LED of the pen-multitester lights up for every "solder bottom" it touches. weird!

  • leybakqeed Apr 30, 2010

    cant i just use a pen-multitester?when i checked it using my pen-multitester, it appears everything is working, i mean the LED of the pen-multitester lights up for every "solder bottom" it touches. weird!



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My first guess would be that the zener diode is probably shorted. Also check the 2N4125 transistor for a short. Start there and update this with your results.


Posted on Apr 30, 2010

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  • ABRsvcs Apr 30, 2010

    The large part is the input or output jack and is not the problem. Unfortunately neither the zener nor the transistor will appear defective. You will need a diode checker to determine the problem. If you don't know anyone local, try locating my ad here on Fixya for direct contact. Perhaps I can help further.




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