Fender Blues JR - No Sound

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Alton, Feb 19, 2015.

  1. Alton

    Alton Member

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    Fender Blues JR - No sound.

    Here's what I've checked and looked at so far:
    1) Powers Up
    2) All tubes glow so heater circuit works
    3) All tubes tested and all are functional
    4)Speaker output jacks - 1 is a poor (loose) connection/other connects fine - both shot with DeOxit
    5) Input jack is missing nut & washer - removed chassis from cab to test input jack - all points showed 0 Ohms on my meter

    Overview of chassis components: power tube sockets had very loose tube pin connections - tubes would literally fall right out without retainer. Preamp tubes were also very loose. Sockets are PCB mounted..Pots seemed all nice and properly connected to PCB. Both transformers are the exposed winding type and no visual evidence of burning or other failure. Visual inspection of circuit components revealed no burning. In fact, by all indications I am the first person to look at this circuit board since it left the factory. If I have time this weekend I will start testing solder joints and components.

    Any hints like known faulty components? Any mod ideas while I have the chassis exposed?
     
    Last edited: Feb 19, 2015
  2. Alton

    Alton Member

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    So, after having gone through the entire circuit, everything worked!?! So I started over and looked real hard at the tube socket pins first. Figured out a way to tighten them up with a jeweler's screwdriver. Put the tubes in and it fired right up. Time to replace all the tube sockets because I'm still not real happy with the fit...still feel loose and sloppy
     
  3. RiftAmps

    RiftAmps Member

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    The ribbon cables in those amps are notoriously unreliable, I would check those for breaks both at the ends and in the centre. If you plan to keep the amp for a long time, I recommend that you replace each ribbon cable with individual leads.
     
  4. DaveKS

    DaveKS Member

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    ???? What tubes you using?
     
  5. swiveltung

    swiveltung Member

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    Do both speaker output jacks work on those or only one? ie: do you have to have one plugged in before the extension one will work?
     

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