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Hot Rod deville Bias??

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  • #16
    To be fair, C37 is part of a charge pump.I just wouldn't say the cap is pumping.
    Forget what I wrote above.
    What I meant is that the cap just does what all caps are supposed to do: It stores and releases charge depending on applied voltage.
    Either a loss of capacitance or excessive leakage current will impair it's ability to do so.
    Same with C43.
    - Own Opinions Only -

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    • #17
      93uf .14 esr using atlas cap tester. c43 was open, got some better caps on the way.
      nosaj
      soldering stuff that's broken, breaking stuff that works, Yeah!

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      • #18
        ESR is not critical here as currents are low.
        Leakage current shows as a DC resistance and can be measured with an Ohmmeter.
        Meter reading should settle at several 100k for an ecap.
        - Own Opinions Only -

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        • #19
          I've had 2 go open circuit. I guess I've been bitten by the Taeyda cheap caps. Have some Nichions on the way.
          nosaj
          soldering stuff that's broken, breaking stuff that works, Yeah!

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          • #20
            I replaced c43, c37 ,CR10, CR15,
            Bias leads disconnected I am reading btween cp15 and cp17 57.5Vac
            cp15 and cp16 28.61Vac
            cp17 and cp16 28.62

            Bias taps hooked back up I get ...

            CR15 Anode side I am only getting -31.92vdc

            What am I missing here A ground connection?
            nosaj
            soldering stuff that's broken, breaking stuff that works, Yeah!

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            • #21
              Is the +/-16V supply good?

              One thing is not clear to me from the schematic: Does the bias winding have a (grounded) CT? Where does CP16 connect?
              - Own Opinions Only -

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              • #22
                What do you read for the LV circuit? R78 and R79 where you should have 33.3V (+/- respectively) on one end and 16V (+/- respectively) on the other.
                This might help determne if you have a problem with the voltage doubler circuit or if something may be drawing too much current. Or (not probable but not impossible) if the winding may be compromised.
                "Take two placebos, works twice as well." Enzo

                "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

                "If you're not interested in opinions and the experience of others, why even start a thread?
                You can't just expect consent." Helmholtz

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                • #23
                  Originally posted by nosaj View Post
                  What am I missing here A ground connection?
                  nosaj
                  Cathode end of CR10 should read zero ohms to negative end of C34.

                  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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                  • #24
                    Originally posted by Helmholtz View Post
                    Is the +/-16V supply good?

                    One thing is not clear to me from the schematic: Does the bias winding have a (grounded) CT? Where does CP16 connect?
                    I wondered that too. I even tried to clarify by looking up other versions of the schematic with no luck. If CP16 is a center tap it should be grounded. Since nosaj measured from either end to of the winding to CP16 I do assume it's a center tap.
                    "Take two placebos, works twice as well." Enzo

                    "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

                    "If you're not interested in opinions and the experience of others, why even start a thread?
                    You can't just expect consent." Helmholtz

                    Comment


                    • #25
                      Originally posted by Helmholtz View Post
                      One thing is not clear to me from the schematic: Does the bias winding have a (grounded) CT? Where does CP16 connect?
                      It should work either way, with a few differences.
                      Attached is the HR Deluxe III schematics. Pg.2 shows both variants of the supply.

                      Attached Files
                      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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                      • #26
                        Originally posted by g1 View Post
                        Attached is the HR Deluxe III schematics. Pg.2 shows both variants of the supply.
                        And both are different from the schematic posted by Tom.?.

                        "Take two placebos, works twice as well." Enzo

                        "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

                        "If you're not interested in opinions and the experience of others, why even start a thread?
                        You can't just expect consent." Helmholtz

                        Comment


                        • #27
                          Originally posted by g1 View Post
                          It should work either way, with a few differences.
                          Attached is the HR Deluxe III schematics. Pg.2 shows both variants of the supply.
                          Yes, but it makes a difference regarding ground return currents and involved components.

                          - Own Opinions Only -

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                          • #28
                            Note that the variant schematics are for the Hot Rod Deluxe and the amp in question is the Hot Rod Deville. That would explain the component allocation differences. Considering the tests and component allocations so far I think we must be dealing with the schematic Tom posted. But the schems g1 provided do clarify CP16 as a CT I think. Or at least very probable.
                            "Take two placebos, works twice as well." Enzo

                            "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

                            "If you're not interested in opinions and the experience of others, why even start a thread?
                            You can't just expect consent." Helmholtz

                            Comment


                            • #29
                              Ok here the solution. after i posted I started resistance checks to ground. They were all good. So 24ish volt i was getting was less than half on a voltage doubler. Caps are good diodes are good, but measuring from Anode of D10 to Kathode of D15 was showing 4.5 megs where it should have been .01 or .02 (cause of probe leads). So i jumpered d10 to d15.
                              Bam Bias voltage in the park biased up 70 mV played in shed for a bit. Sounds good.
                              nosaj
                              soldering stuff that's broken, breaking stuff that works, Yeah!

                              Comment


                              • #30
                                Originally posted by Chuck H View Post
                                Note that the variant schematics are for the Hot Rod Deluxe and the amp in question is the Hot Rod Deville.
                                The top supply (pg.2 of schems from post #25) is labelled 'HR Deville. It is using the 0041752 xfrmr which is also shown in the snippet Jon posted in post #7, and the schematic that Tom posted.
                                I realize that doesn't clarify much but it seems it has been drawn with both the CT connected and not connected.

                                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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