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Hartke 7000 switch problem?

Discussion in 'Amps and Cabs [BG]' started by Johnny Fila, Jan 8, 2005.


  1. Johnny Fila

    Johnny Fila Formerly "The Crusader"

    Nov 21, 2004
    Elmont, NY (near NYC)
    Anyone ever have any trouble with the switches on these heads? I just blew another switch in a few years and i never play out...any ideas why this happens? the switch has 6 prongs (3 by 3) so I moved the wires over to the left side. Seems to work for now, but...........any help is appreciated. Thanks.
     
  2. Tim__x

    Tim__x

    Aug 13, 2002
    Alberta, Canada
    Which switch? Power? If so you can increase it's life by soldering a small 600v cap across it.
     
  3. I've had power switches go out in lots of amps. Fortunately they usually fused "on".

    The reason: traditional power amps use a big power transformer. So when you turn the power switch on, there's a huge inrush current while the PT and filter caps charge up. (That's why amps usually use slo-blo fuses...)

    Then when you turn the amp off, this same stored energy can discharge back through the switch's contacts as the contacts are being broken. A miniature arc welder develops, for a few milliseconds.

    Cheap switches, and even moderately-priced switches, can't cope with the continual abuse of their contacts, eventually the contacts fuse together.

    I'd pull the switch out and take it to a good local electronics parts store--one that sells resistors, capacitors, transistors, NOT Circuit City or Electronics Express or even Radio Shack. Switches are made to fit common opening sizes, and the salesman should be able to fix you up with a better quality switch for $5 give or take.
     
  4. Johnny Fila

    Johnny Fila Formerly "The Crusader"

    Nov 21, 2004
    Elmont, NY (near NYC)
    Yes it's the power switch. It seems to have some sort of blue colored capacitor going from the white wire in to the white wire out (what does that do ?). I jumped the wires over to the other side for now...but is that a bad idea? thanks.
     
  5. Johnny Fila

    Johnny Fila Formerly "The Crusader"

    Nov 21, 2004
    Elmont, NY (near NYC)
    OK, i saw the arc occur. the switch has 6 prongs (3x3) can i use the other side?
     
  6. Yes, it's a DPDT switch, meaning when it opens and closes it's making/breaking two set of contacts. The other side is independent of the first side. So moving the wires to the other side doesn't matter.
     
  7. But I'd still go on and replace the switch.
     
  8. Johnny Fila

    Johnny Fila Formerly "The Crusader"

    Nov 21, 2004
    Elmont, NY (near NYC)
    Thats what I figured, cause the one side looks fried. I'll take you advice and change it. Thanks for the help, I appreciate it :)
     
  9. Tim__x

    Tim__x

    Aug 13, 2002
    Alberta, Canada
    Yes, that's why I suggested the cap. I'm suprised that it failed with a cap already installed.