Home › Forums › Help/Technical Questions › Electric mistress deluxe V2 no signal at lm741

Viewing 8 posts - 1 through 8 (of 8 total)
  • Author
    Posts
  • November 9, 2014 at 6:27 pm #83705
    Darenzo
    Participant

    Hey guys I hope someone can help me on this.!!
    I have an Electric mistress deluxe V2 in for repair that has 14v dc on pin 2 of lm741 ??
    So I am not getting any input signal past the 27nf cap on the way in..
    Following Ralf Metzger’s excelent troubleshooting guide my pedal checks out until I try and trace the input signal through the board ..The pedal works fine in bypass but nothing when the circuit is switched in ..
    Thanks for your help Dazza :)

    November 10, 2014 at 7:36 pm #120370
    Darenzo
    Participant

    Bump !!

    November 11, 2014 at 4:09 am #120372
    Scruffie
    Member

    Post the full voltages for the 741, SAD1024 and 4558.

    November 11, 2014 at 9:00 am #120374
    jani
    Member

    Want to know what the current draw is for a particular EHX pedal? This will be a good place to ask. We’ll check the thread and find answers as often as we can.

    November 11, 2014 at 10:12 pm #120375
    Darenzo
    Participant

    Hi the voltages are….

    741
    pin 1: 0v
    pin 2: 8.57v
    pin 3: 8.64
    pin 4: 0v
    pin 5: 0v
    pin 6: 8.72
    pin 7: 14.96
    pin 8: 0v

    4558
    pin 1: 14.51v
    pin 2: 14.31v
    pin 3: 3.83v
    pin 4: 0v
    pin 5: 8.6v
    pin 6: 8.7v
    pin 7: 8.7v
    pin 8: 14.95

    SAD1024
    pin 1: 0v
    pin 2: 14.5v
    pin 3: 7.48v
    pin 4: 0v
    pin 5: 14.3v
    pin 6: 8.72
    pin 7: 14.3v
    pin 8: 7.4v
    pin 9: 14.3v
    pin 10: 7.48v
    pin 11: 14.3v
    pin 12: 8.9v
    pin 13: 0v
    pin 14: 7.4v
    pin 15: 14.8v
    pin 16: 0v

    cheers :)

    November 12, 2014 at 7:14 am #120377
    Scruffie
    Member

    The problem is at the first half of the 4558, dig around and find out why pins 1 & 2 are 15V (should be about half supply).

    November 12, 2014 at 9:49 pm #120391
    Darenzo
    Participant

    Scruffie !!
    Thank you so much dude for your help ..
    The problem was the 4558 .. After replacing it the pedal sprang to life and the voltages dropped to normal ..
    Another vintage pedal saved !

    all the best
    Dazza :)

    November 13, 2014 at 12:45 pm #120393
    Scruffie
    Member

    Always glad to help stop vintage EHX becoming a door stop ;)

  • Author
    Posts
Viewing 8 posts - 1 through 8 (of 8 total)
  • You must be logged in to reply to this topic.