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Fender Blues Junior Light not working

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  • Fender Blues Junior Light not working

    Hi!

    I've been working on building an amplifier head around a Blues Junior PCB I got for cheap some time ago. With the help of this forum and online resources, I managed to hook up everything, and it works almost perfectly. The amp powers up fine, and it sounds very good, all the controls work as well.

    However, I can't seem to get the pilot light to work, and I don't really know where to start trying to fix it.. Hoping someone familiar with the Blues Junior, or tube amps more generally, can help.

    I've attached the schematic. The pilot light I'm trying to use is this one: https://www.ebay.de/itm/122992423946?ul_noapp=true. I've tried replacing the 230VAC bulb with a 6.3V one, but it didn't make a difference.

    The circuit is essentially the Blues Junior, but with a standby switch mod (http://jwguitarworks.blogspot.com/20...ification.html), upgraded capacitors, cathode follower mod, and presence control mod, plus new power and output transformers. Wires to the pilot light are still the same from the original circuit.


    Any help is greatly appreciated!
    Attached Files

  • #2
    Where did you connect the new pilot light?
    Original circuit requires a red LED. 230V bulb would be connected across PT primary (black and white wires). 6.3V bulb should be wired to the heater winding (green/green).
    - Own Opinions Only -

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    • #3
      In place of the LED, which really makes no sense when you spell it out like that..

      Is there any way to add a pilot light to the circuit, or better to stick with the LED? Any particular one I need to get?

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      • #4
        See above.
        - Own Opinions Only -

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        • #5
          This is the factory LED assembly.
          https://darrenriley.com/store/fender...00-0056975000/
          Last edited by Jazz P Bass; 10-06-2020, 03:37 AM.

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          • #6
            Originally posted by clarisso11 View Post
            In place of the LED, which really makes no sense when you spell it out like that..

            Is there any way to add a pilot light to the circuit, or better to stick with the LED? Any particular one I need to get?
            You can use the pilot light you bought. Just hook it across the transformer primary (but after the switch) as Helmholtz already noted.
            "I took a photo of my ohm meter... It didn't help." Enzo 8/20/22

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            • #7
              Today I was triggered into the grammar nazi mode, for good reason.
              Technical questions and answers must be spelled clearly, or will be wasted.

              Where did you connect the new pilot light?
              Original circuit requires a red LED. 230V bulb would be connected across PT primary (black and white wires). 6.3V bulb should be wired to the heater winding (green/green).
              In place of the LED, which really makes no sense when you spell it out like that..
              And you are right.

              It should have been split into separate ideas (which they are), as written it looks like all should be done at the same time ... which makes not sense of course.

              It should read:
              Where did you connect the new pilot light?

              Original circuit requires a red LED.

              230V bulb would be connected across PT primary (black and white wires).

              6.3V bulb should be wired to the heater winding (green/green).
              Any clearer now?
              Juan Manuel Fahey

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              • #8
                All working now, thanks everyone for your help!

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