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Thread: Power Amp - Replacement Power Switch

  1. #16
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    The switch body often snaps together and can be pried apart, has small screws, or sometimes rivets which can be drilled out.
    This is more true of older switches than the newer ones. Things used to be made to be repairable. Now everything seems to be made to sell you the next one.

    My recent switch repair was a slide switch that stopped making contact. Those can usually be taken apart and tweaked. Turned out this one was a double throw switch so all it needed was a lead removed from one terminal and soldered to the unused terminal. If it dies in the future there might be one of the right size in my parts piles or at least the right size is known.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  2. #17
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    Quote Originally Posted by Jim Koepke View Post
    This is more true of older switches than the newer ones. Things used to be made to be repairable. Now everything seems to be made to sell you the next one.
    I suspect it is more to save a dime on the production cost than planned obsolescence, but maybe it's some of both. I do admit to not being easily deterred. Sometimes things are heat welded/glued together making them harder to get apart. A very thin saw is sometimes useful here.

    The little very thin circular saw blade made for Dremel is probably the best. Hand saws next, then Fein multitool, but the blade on the multitool is a thicker.

    I think most rocker switches, however, are still snap-together since that is cheap to make - the body is a one piece "box" with the contacts molded in place for rigidity and alignment. The rocker is pressed into the rectangular opening at the top by spreading the plastic a bit so the nubs molded on the rocker snap into place to form the rocker axle. (These sometimes have little ramps or slopes molded on the pieces so they snap together a lot easier than they come apart.) To remove, insert a thin, sharp spatula or knife in the crack near the center of the rocker, pry the case outward and pop the rocker out. Watch out, loose pieces may fly. (I once lost a tiny ball bearing detent in a switch by foolishly disassembling the switch over a pile of sawdust at the lathe! Eventually found it with a magnet.) In my experience it is more common than not to find a switch that can be repaired.

    JKJ

  3. #18
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    Sometimes things are heat welded/glued together making them harder to get apart.
    On my last encounter with a small case put together in this manner, the case was placed in my large vise and slowly compressed. When a slight pop was heard it was inspected to see where it had opened and another vise compression was used to pop the other side.

    A zip tie was used to hold the case back together.

    jtk
    "A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
    - Sir Winston Churchill (1874-1965)

  4. #19
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    I bought a very similar rocker switch from mouser electronics about 10 years ago. It cost lass then a dollar.
    For the next 5 years after that I received a mouser catalog in the mail that weighed about 12 pounds, and had millions of electronic parts in it.

  5. #20
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    Well, today I pulled the amp out of the sound booth and brought it home with me. I just got the broken switch out of the chasis. The swith is rated for DC 12V - 30 Amp and is a R13-133. The swith has 3 conductors on it but only 2 of them were hooked up to the amp wiring. The switch says:
    Earth
    Load
    Supply
    The earth connection was not used. So in my simply mind, this switch could have just as easily been a common single pole switch for your home.
    I'm thinking that if I can find a toggle switch locally that is AC 120V - 20 Amp, I should be good to go. Thoughts???
    Thanks & Happy Wood Chips,
    Dennis -
    Get the Benefits of Being an SMC Contributor..!
    ....DEBT is nothing more than yesterday's spending taken from tomorrow's income.

  6. #21
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    determining the switch rating

    Quote Originally Posted by Dennis Peacock View Post
    Well, today I pulled the amp out of the sound booth and brought it home with me. I just got the broken switch out of the chasis. The swith is rated for DC 12V - 30 Amp and is a R13-133. The swith has 3 conductors on it but only 2 of them were hooked up to the amp wiring. The switch says:
    Earth
    Load
    Supply
    The earth connection was not used. So in my simply mind, this switch could have just as easily been a common single pole switch for your home.
    I'm thinking that if I can find a toggle switch locally that is AC 120V - 20 Amp, I should be good to go. Thoughts???
    Dennis,

    Yes, a single-pole single-throw switch. But what current rating is needed?

    You might check to see if the amplifier itself has electrical specs on a plate or sticker on the back to see what switch rating is actually needed. It it typical to use switches rated higher than the load for no reason other than availability. If the sticker is missing, I personally would jumper the power switch, put a current meter in line (or use a clamp-on) and measure the actual current use with the amplifier running at the usual power. (This method may not be best if lacking experience with electrical equipment.) You might be able to use a switch with lower ratings than listed on the switch.

    Another hint may be the size of the wires connected to the switch and the size of the wires in the power cord. A 20 amp load is a LOT of power and requires large wires, typically 12ga. (This isn't a massive amplifier such as used in outdoor arenas, is it?)

    The picture of your switch looks like it has a pilot light that is supposed to come on when the switch is turned on as does the terminal labeling. (I don't know why they would use this type of switch in an application with an obvious power indicator light mounted next to it - maybe someone replaced it once before and used whatever switch they could find.) I'd have to check but I believe the earth terminal is connected to ground when you want the light to turn on when you turn on the switch. If not using the indicator light in the switch, any toggle switch of sufficient rating or higher will work. In fact, I had a rocker switch that looked much like yours that mounted in a round hole drilled in the chassis - a standard toggle switch may fit in the same hole. Do you have a Radio Shack or an electrical supply house nearby?

    I sure wished I lived around the corner from you! I'd probably find a switch in my parts bins or pull one from an old piece of equipment and just come over there and fix it!

    JKJ

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