circuit build keeps on killing power supplies. culprit?

Discussion in 'The Projects Forum' started by Videodrome, Aug 14, 2010.

  1. Videodrome

    Thread Starter Member

    Nov 12, 2009
    wired up a guitar synth circuit this afternoon and was surprised to find that it burned through not 1, not 2, but 3 power supplies all within about an hour of eachother trying to get it powered up. these supplies were brand new so i do not think that its an issue regarding faulty units but with the circuit itself. i made in error in the circuit itself which i have to go back and troubleshoot but im suspect that even that error could cause a failure in whatever power supply is plugged into it. i'm using the exact power supply that is suggested. does anyone have any idea as to where to start troubleshooting such an issue? i dont have a schem of the circuit to put up for reference so any input is appreciated, general or precise. thanks again folks.
  2. someonesdad

    Senior Member

    Jul 7, 2009
    Find out what failed on the power supply; this should let you make a beginning hypothesis about the cause of failure. Two reasonable hypotheses are a) the load causes too large of a current and b) the load causes too large of a voltage. b) isn't likely unless there are inductors and switching currents involved. Thus, a) is a good working hypothesis. You could test it by shorting the output of the power supply and see if you get the same failure mode.
  3. windoze killa

    AAC Fanatic!

    Feb 23, 2006
    I would install a current meter. See how much your circuit is drawing. It is almost for sure the reason your PSUs have died. I suggest you install some fuses also if you haven't got anything to measure current.

    Can you describe the type of PSU you are killing? Also is there anyway of drawing a schematic?

    You could also measure the power input resistance of your circuit. This doesn't always indicate the problem but may help.

    Also you haven't actually said if the circuit is working for a while before the PSU dies.
  4. retched

    AAC Fanatic!

    Dec 5, 2009
    If the power supplies are generic types, they may be manufactured for both 220v and 120v (UK and US) markets. If they failed to place the internals into the proper pronged shell, you may have 240v transformer internals inside a 120v box. This could be a reason for the failures.

    Are you in the US or a 240v using country?