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5C1 Champ build heater supply problem

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  • 5C1 Champ build heater supply problem

    I am nearly done my first scratch build, a 5C1 Champ. Upon firing it up for the first time, or trying to, the pilot light lit up but the 6V6 and 6SJ7 did not. As per the standard layout the light is first on the heater lead. I unhooked the light and skipped it altogether. The amp sounded magnificent, even with me playing it. No humms, buzzes or anything. I tried a completely different design of light and got the same thing. No tubes lighting up.
    I am using a brand new 291AX Hammond transformer bought specifically for this build. Any suggestions on what might be amiss? I will bypass the light completely but I would like to have a pilot light.

  • #2
    Just guessing but maybe you don't have the bulb socket insulated from the chassis?
    Originally posted by Enzo
    I have a sign in my shop that says, "Never think up reasons not to check something."


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    • #3
      I am reasonably sure both different lights had sockets insulated from the chassis, but then ??? wouldn't it just have shorted out?

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      • #4
        If you are using the old school filament supply wiring of Fender....
        look at the single wire to the socket and socket lug grounded to the chassis (the return filament supply lead) used in old Fender amps... then look at the way the pilot lamp assembly is wired when it is done that way.
        I'm betting you have one or the other wires grounded wrong with respect to the pilot lamp assembly.
        Bruce

        Mission Amps
        Denver, CO. 80022
        www.missionamps.com
        303-955-2412

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        • #5
          Fender Champ 5C1

          The original Champ 5C1 had one end of the heater winding tied to ground.
          So one of the lamp filament wires must go to ground.
          Any chance that you had the lamp wired in series?
          Attached Files

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          • #6
            I indeed have the lamp wired in series with the tube heaters as that is what the layout diagram looks like. So if I tied the green wire from the PT and the lead to the 6V6 filament to one lug of the lamp, and grounded the other lug, that should do it? Just a bit confusing.

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            • #7
              Yeah, there is not any indication that the lamp itself is grounded.
              Then again, there is only one green wire going to the lamp.(the other heater green is shown at chassis ground)
              So that right there 'implies' that the lamp is grounded.
              All heater connections should be in parallel.

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              • #8
                Got the light wired up properly in parallel this morning and it works like a charm. Looks good and sounds good. I hope to get it all buttoned up today. Thanks.

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                • #9
                  I haven't been able to post pictures here since last November when I got a new laptop with Windows 8. A thread I read recently suggested the problem was with the browser not the sight. I am now trying Chrome and we will see, however if the site does not recognize the most widely used browser, the problem is with the site. It works with Chrome. Here are some shots of the Princeton SS converted to tubes. some fun!


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                  • #10
                    Don't assume the site has the issue because the browser is popular. MY Internet Explorer, a VERY widely used browser, has managed to slip a bit somewhere, and I cannot attach files to anything, not here, not even my email. it isn't something Microsoft did, it is the browser copy in my computer that is defective. I also cannot open certain things on some sites. I have Chrome on here. I am not sure I am a fan, but it seems intact, as from it, on this same computer, I can upload files as well as download from the other places.
                    Education is what you're left with after you have forgotten what you have learned.

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                    • #11
                      When I upload a pic here with IE8, it redlines my CPU at 100%. I can kill IE8 with the TaskManager, reload saved content, the pic is in my attachment folder (under Manage Attachments) and I can attach it to my post. I don't have a problem on other sites including the Sunn site hosted on the same server.
                      WARNING! Musical Instrument amplifiers contain lethal voltages and can retain them even when unplugged. Refer service to qualified personnel.
                      REMEMBER: Everybody knows that smokin' ain't allowed in school !

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                      • #12
                        I am running IE8 (XP) on one of my computers.
                        I cannot upload files in one shot.
                        The upload stops at half way.
                        IE9 is fine (Vista)

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