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Marshall Jcm2000 slow to poweron

Discussion in 'Marshall Amps' started by The Dude, May 17, 2021.

  1. The Dude

    The Dude New Member

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    Question. Have a Jcm2000 Dsl100. When i first hit power switch on, lately it takes about 5- 8 seconds before light comes on and she comes to life , tubes are new, been in about a yr but has not been played alot only happens when i let sit for like an hour or so. If i turn off and then back on i say 5 min it dont seem to happen amp has been biased and checked over again on bias. 2009 mlbjcm2000. Thanks in advance for you ideas
     
  2. PelliX

    PelliX Well-Known Member

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    Capacitors. They discharge when you're not using the unit but will retain their charge for a period of time, gradually discharging. Get it to your tech, it's a straightforward job, really.
     
  3. The Dude

    The Dude New Member

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    Im not having any other issues with hum, or crackle sounds or anything, i can crank it to 10 and its sounds just like a new amp. No hissy noises anything. Shouldnt it be making strange sounds if the caps are going out. Besides just a slow power up ? Curious
     
  4. Travis398

    Travis398 Well-Known Member

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  5. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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  6. Neil Skene

    Neil Skene Well-Known Member

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    Mine has been doing this for ten years.
     
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  7. PelliX

    PelliX Well-Known Member

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    Well, that's a standard mechanical switch, it should not incur a delay. The llight inside the switch may need a moment to light up, but I've never come across that myself - either they work or they don't work ('work' includes flickering). The filament in the switch can't really be inline with the load behind it. To test, just bypass the switch (disconnect the contacts and bridge them) and power it on by plugging it in or flicking the switch on your power source/power strip/etc. If that does indeed resolve the issue, I stand corrected!
     
  8. The Dude

    The Dude New Member

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    Ok i tested it with the power switched to on. I put it on a surge protector and the second i hit the protector switch it fired right up. My question now is if i get a new switch. Is it user friendly to replace or is it a deadly situation that needs to be taken to a tech. Wondering if capacitors will travel back and bite me in the ass on a switch replace or if its safe to do yourself ? Anybody ????
     
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  9. Dogs of Doom

    Dogs of Doom Moderator Staff Member

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    it's simple...

    You just have to make sure to get the right one.
     
  10. Travis398

    Travis398 Well-Known Member

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    It's very easy, assuming you unplug the amp. Refrain from touching other things or you could use a meter and verify all caps are drained before doing the job.
     
  11. AdrianDSL

    AdrianDSL Active Member

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    How can this be tested with a multimeter?
     
  12. PelliX

    PelliX Well-Known Member

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    Set the multimeter to DC Volts (and if applicable on your meter, to a voltage range greater than the voltage of the cap) and measure across the terminals. If there's a charge, either wait or use a 10K 1W (or greater wattage) resistor to 'short' the terminals. Obviously, do not touch the contacts of the capacitor or resistor before or while doing this. The resistor will effectively dissipate the residual charge as heat.
     
  13. AdrianDSL

    AdrianDSL Active Member

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    Simple and logical, thanks!
     
  14. The Dude

    The Dude New Member

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    Well if antone has replaced their switch. Would like to know in advance if there were any hot leads. Capacitor voltage at the switch wires.
     

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