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My new toy :)

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  • My new toy :)

    Moderators, I didn't see a section for test gear so I thought I'd put this here since I will be using it to test caps for guitar amps.
    Please move if this is not the appropriate place for this.
    Thanks!

    So my new toy is in very nice physical condition, but I may have to do some work before plugging it in.

    Those caps look positively ancient!

    The seller already powered it up to show that the magic eye tube works, but I still think I'd better check out those caps first.
    Attached Files
    If it ain't broke I'll fix it until it is...
    I have just enough knowledge to be dangerous...

  • #2
    Now you need to buy a cap tester to test the caps in your cap tester.
    "I took a photo of my ohm meter... It didn't help." Enzo 8/20/22

    Comment


    • #3
      Ha ha
      Yes, the irony was not lost on me.
      If it ain't broke I'll fix it until it is...
      I have just enough knowledge to be dangerous...

      Comment


      • #4
        My favorite piece of gear. I had an old Eico 950B which is very similar. It puts real world voltages on caps, so you really can test a cap at 400v for leakage. And leakage is what matters. It really doesn't matter much if your coupling cap is 0.019 rather than 0.022, but it does matter if it leaks like a screen door at anything over 200v.

        Good, clean looking unit.
        Education is what you're left with after you have forgotten what you have learned.

        Comment


        • #5
          Thanks Enzo.

          That's why I bought it, for testing leakage.

          I knew it could be done, (and I have the feeling I've changed quite a few caps that didn't need changing) but no modern testers do that.

          So I came across this website...

          http://www.angelfire.com/electronic/...at_I_need.html

          ... and he recommended the Heath IT-11 or IT-28.
          A couple came up on ebay but out of my price range.

          Then my search found this Heath C3 that looked really nice and I could afford.
          Not quite as fancy as the other two but should suffice.
          If it ain't broke I'll fix it until it is...
          I have just enough knowledge to be dangerous...

          Comment


          • #6
            Yep, those two are more the prize, but nothing wrong with what you got. The recommended ones are just a little more featurely.
            Education is what you're left with after you have forgotten what you have learned.

            Comment


            • #7
              The Sencore LC models are very nice, if you happen to have a extra $1000.

              Comment


              • #8
                Originally posted by mozz View Post
                The Sencore LC models are very nice, if you happen to have a extra $1000.
                I'm sure they are nice, but for that much... ain't gonna happen.
                If it ain't broke I'll fix it until it is...
                I have just enough knowledge to be dangerous...

                Comment


                • #9
                  Deja Vu

                  My dads television work bench had a similar tester, I thought the indicator eye in the upper left corner was cool. By the early 70's I was into solid state electronics. Ironically by the late 90's tube guitar amps were on my bench.

                  Comment


                  • #10
                    Work has been progressing on the cap checker.

                    Still waiting for the 8uf supply caps.

                    I rewired it with colored stranded wire.
                    Originally it was wired with solid core and all the same (green) color.
                    Replaced all parts (caps and R's) that were quite far out of tolerance.
                    Some of the originals were still good.

                    Found a nice manual for it.
                    Drat, tried to upload it but the pdf is too big.
                    Here's a different one, not as nice but has the essentials.

                    Edit; here's a link to the nice manual download if anyone wants it.

                    https://archive.org/details/Heathkit...rCheckermanual

                    I installed a 3 wire grounded power cord.
                    Should I leave out the line to chassis .05uf cap?
                    Attached Files
                    Last edited by galaxiex; 05-20-2018, 01:25 AM.
                    If it ain't broke I'll fix it until it is...
                    I have just enough knowledge to be dangerous...

                    Comment


                    • #11
                      Nice toy OP.

                      But my cap tester is something RG posted here years ago: a resistor in series with a cap under full voltage. If there's voltage on that resistor, the cap leaks. Sometimes I'll rig this up on a protoboard and test 10's of caps and then dismantle it.

                      But seeing the result on a cat eye tube is a higher level of tubromance no doubt about it.
                      Valvulados

                      Comment


                      • #12
                        Final parts came today so I got to finish up this project.

                        Was waiting for the two 8uf filter caps.

                        The 2 dark ones bottom center.

                        Click image for larger version

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                        Top side guts final.

                        Click image for larger version

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                        200K calibrating resistor, pretty close.

                        Click image for larger version

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                        Had to test all the caps that got replaced in this unit.
                        All are leaky and some don't read *any* value at all.

                        Click image for larger version

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                        These are from the 1970 Traynor Guitar Mate I've been working on.
                        All blue caps are leaky (no surprise) values test ok.

                        All yellow caps test good for value and leakage.

                        Click image for larger version

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                        And finally the main filters from the 1970 Traynor.
                        I was really questioning these whether I had to replace them or not.
                        Amp "seemed" to work ok with them.
                        These are the originals with 1970 date code.
                        They leak.
                        With the new caps the amp is punchy and LOUD!

                        Click image for larger version

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                        If it ain't broke I'll fix it until it is...
                        I have just enough knowledge to be dangerous...

                        Comment


                        • #13
                          Out of curiosity, did you happen to test the new caps for the amp before installation? Always good to check for comparison.
                          Originally posted by Enzo
                          I have a sign in my shop that says, "Never think up reasons not to check something."


                          Comment


                          • #14
                            Originally posted by g1 View Post
                            Out of curiosity, did you happen to test the new caps for the amp before installation? Always good to check for comparison.
                            Unfortunately, no.
                            I had replaced those caps some time ago and only got this tester up and running today.
                            The amp is all back together... but I spose I could pull the chassis and check them... maybe later....

                            FWIW the old caps tested spot on for value, just leaky.
                            If it ain't broke I'll fix it until it is...
                            I have just enough knowledge to be dangerous...

                            Comment


                            • #15
                              Originally posted by galaxiex View Post
                              FWIW the old caps tested spot on for value, just leaky.
                              That's what kind of made me wonder how the leakage is calibrated and how leaky the new caps would check out to be. Good to have a reference from some new caps.
                              Originally posted by Enzo
                              I have a sign in my shop that says, "Never think up reasons not to check something."


                              Comment

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