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Help! Fender Blues jr. III ,blown power tube

Discussion in 'Glowing Bottle Tube Amp Forum' started by braveheart, Aug 26, 2020.

  1. braveheart

    braveheart Tele-Afflicted

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    I switched on my amp...no tone

    and one of the power tubes flickers purple
    [​IMG]

    what can I do?
    Is it just the tube?
    can I put in a spare tube to test if it's just the tube?

    I hope somebody can help...:(:cry::cry::cry:
     
  2. Les Paul lover

    Les Paul lover Tele-Holic

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    It may be just the valve....

    You can replace just the offending valve (very pretty!!!!) to see if that solves the issue, but you would really need, if that is the issue, to replace both power valves with a matched pair.
     
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  3. Matthias

    Matthias Friend of Leo's Gold Supporter

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    When mine did that, the screen grid resistor went too... Put a new matched pair in and if you don’t get weird overtones and early break up, you’re good.
     
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  4. dan40

    dan40 Tele-Afflicted

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    If you buy a new set of tubes, it would be wise to let the tube seller know that you need a pair for a Blue Jr. The amp is grid biased but there is no bias pot to adjust the actual current draw. If the seller knows that you are purchasing for a Blues Jr, they can send you a pair that will bias up well in the circuit.
     
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  5. hepular

    hepular Tele-Meister

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    if i'm seeing correctly, i'm also concerned by what looks to be the lack of any heater action in v1 (or maybe it's v2--preamp tube to far right in pic looks as though nothing's happening)
     
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  6. braveheart

    braveheart Tele-Afflicted

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    I switched on the amp just for a few seconds to make a quick foto....but I remember they were glowing the day before when I checked the amp..
     
  7. braveheart

    braveheart Tele-Afflicted

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    Yes, I've already heard that the BJR is notorious for its high "power tube smoking" bias...so I think about doing this mod

     
    Last edited: Aug 28, 2020
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