Blown Power Supply?

Discussion in 'General Electronics Chat' started by kgrs, Nov 5, 2011.

  1. kgrs

    Thread Starter New Member

    Nov 5, 2011
    I just got a script 90 (led + dc) I was so anxious to test it and had no 9v batteries so I gathered some old walwarts and grabbed one that (I thought) was suitable ie 9v dc @ 450 ma. I plugged it in and the led came on, then whent dim and then went off. Upon inspection I discovered that it wasn't 120 v ac to 9v dc, it was 120v ac to 9v ac! Now the box doesn"t work (except by-pass) no led and no effect. How much damage have I done and is it fixable? Thanks,
  2. Wendy


    Mar 24, 2008
    Welcome to AAC!

    A thread belongs to the OP (original poster). Trying to take over someone elses thread is called hijacking, which is not allowed at All About Circuits. I have therefore given you a thread of your very own.

    This was split from:
  3. Wendy


    Mar 24, 2008
    A LED is a diode, you must use a resistor when using one. You would have blown any power supply your tried using this. I have written a tutorial on LEDs, then went on to write a lot more. To understand LEDs you need to cover Chapter 1 and half of Chapter 2.

    LEDs, 555s, Flashers, and Light Chasers

    It sounds like you blew the transformer (or it would have not faded out). Generally wall warts are not meant to be repairable, though I have done it by carefully cutting the case in half and replacing the fuse.
  4. praondevou

    AAC Fanatic!

    Jul 9, 2011
    Are you talking about this one?

    Did you open it up and is it this board?

    I don't have schematic or something but it should be able to repair this putting some effort in to it.
  5. SgtWookie


    Jul 17, 2007
    OK, in this thread you mention a "script 90", in the other thread you mention a "phase 90".
    What is the actual name of the effect pedal?
    Is it a homebuilt, or a commercial one?
    If commercial, what's the exact model?
    Here's a link to an old Phase 90 design:
    More hits in this Google search:,cf.osb&fp=44eaab8c14888b01&biw=1268&bih=731
    MXR Phase 90/180

    You may have fried all of the opamps and diodes. It'll be tough to tell remotely.