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Effects Gizmo - terrible buzz/noise when plugged into front input

Discussion in 'Effect Gizmo / RG-16 / Rack Gizmo / Mini Effect Gi' started by darcym, Aug 31, 2019.

  1. darcym

    darcym
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    I'm re-writing my rack with a new RJM effects gizmo,

    I decided to do some individual loop testing to make sure where was no problems before bolting it all in place and finding a problem.

    When I plugged the guitar into the front input on the effects gizmo there is just a terrible loud buzz so loud you can't actually here the guitar, it's like a very faint noise I the background.

    If I plug it into "input 1-4" in the back the unit works fine, clear sound and the loops are working, so I'm confident no problem with any of the cables in the gizmo loops or the cable to the amp (obviously done the stand alone testing of cables etc too)

    What would cause the front intput to be totally unusable, but the back "input 1 - 4" to work fine, is it likely to be something like a loose cable on the front jack inside - or more likely to be my wiring configuration, I only ask as I don't want to take the lid of this thing to even look unless I have to.
     
  2. darcym

    darcym
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  3. rjmmusic

    rjmmusic
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    I suspect that the cable linking the front panel jack to the main circuit board is broken. We can sell you a new jack assembly (or just send it to you if it's under warranty). Depending on the age of the Effect Gizmo, replacement may or may not require soldering. You can send it in to us, also.
     
  4. darcym

    darcym
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    it's only a couple of months old - I bought it as a replacement / additional gizmo while I got someone to repair my old one which you kindly sent the CPU for. I can't really send it back from the USA from the UK for a jack socket assembly. I can supply the serial number if that helps know if it needs soldering or not.

    happy to pay for the part to be posted out to me in the UK, just keen to get it setup now that everything is falling into place.
     
  5. rjmmusic

    rjmmusic
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    If you bought it recently, it definitely won't require soldering. We made that change years ago.

    If you have a meter, it would be helpful to plug cables into the front input and the From Front jack on the rear, and measure to see if there's continuity from tip to tip and ring to ring.

    In any case, I can send you a replacement jack, but it would be better to know that the problem is what we think it is.
     
  6. darcym

    darcym
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    found my multi-meter, going to need some basic instructions on what to do to get you the info you need (sorry)
     
  7. rjmmusic

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    Plug a cable into the front input, and plug another cable into the From Front jack. Set your meter to measure ohms. You'll be measuring from the plug on the free end of one cable to the plug on the free end of the other. First, measure the tip of one plug to the tip of the other. It should measure close to 0 ohms. Then, measure the sleeve of one plug to the sleeve of the other. It should also measure close to 0 ohms.
     
  8. darcym

    darcym
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    I'm %99 certain I've done this right, but just to confirm set the meter to ohms, plugged the two cables in, one to the front one to the "from front" in the back. Power the effects gizmo unit on.

    Touching the unplugged and of the cable at the tip of the cables in the front and from front inputs with the tip of the probes I get wild readings - the number never gets close to a static range and just jumps around everywhere.

    Touch the sleeve of the cables in the front and from front inputs with the tip of the probes I get a very low reading 000.7 to 000.9

    Does that help ?
     
  9. rjmmusic

    rjmmusic
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    Yes, that means the connection on the tip is probably broken or intermittent, and that would definitely cause the symptoms you're seeing. If you don't might getting inside the unit, I could send you a replacement jack assembly - you just need to take the lid off unscrew the jack from the front panel, and unplug it from the circuit board. Then, reverse the process to install the new one. Or, you can send it in to us.
     
  10. darcym

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    that would be perfect, I can more than manage the work you describe, thank you.
     
  11. rjmmusic

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