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full schematic SWR workingsman

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  • full schematic SWR workingsman

    Hello from Argentina, im looking for the swr workingsman schematic, i have one part from this thread

    http://music-electronics-forum.com/t7538/

    So im asking id anbody have the other part, especially in need to know all those w points where they go, there is a compression part o something like that.

    Thanks for al the help.

    Saludos.

  • #2
    The schematic in the thread you linked is the whole schematic for the Workingmans 10. There is no more than that.

    Do you have some model different from the Workingmans 10?

    What is missing from your schematic?
    Education is what you're left with after you have forgotten what you have learned.

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    • #3
      There is an older version of the Working Man's 10 bass amp that doesn't use the TDA7294 chip, but power transistors (2SA1943 and 2SC5200) in a push-pull configuration for the output.

      I have one of these in my shop and there doesn't seem to be a schematic anywhere for this. The board I have is marked "WKG10 #1 Bottom Rev D" and on the component side is silk screened "WORKING MAN'S 10", "MANUFACTURED BY SWR", "WKG #1 SILK REV D".

      The board was damaged (burnt badly) after one of the power transistors shorted causing the driver transistor to fail, which burnt the resistor to it.

      The customer wants the silly thing fixed(!) even though the repair is going to cost more than what the amp is worth. I'm down to pulling parts off the board so I can trace out the schematic manually (double sided board, with through-hole vias, at least it's only two sides) but was hoping someone might know where the schematic or other info may be. Fender doesn't have it, they only list the TDA chip version

      Thanks!
      Last edited by HutchAmpMan; 10-29-2019, 10:04 PM.

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      • #4
        Here is a schematic of the WM10 with discrete output devices.
        Workingman's 10 discrete.pdf

        Not too sure about "but power FETS for the output." as this schematic shows bjt outputs.

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        • #5
          Thanks for the info

          Thanks for the schematic, it's not quite what I have but closer than the TDA output version.

          I edited the post as in my "drain bamaged" state I mixed the outputs up with another bass amp (Carvin) that used FETs.

          The outputs are indeed, BJT, 2SA1943 and 2SC5200. The thing also runs +/- 45 volts on the rails and +/- 15 volts for the op amps (NJM2082L SIP Vs the TLO72 DIP used in the later amps). It would seem to pre-date this schematic also.

          I have it in my office now with most of the larger components removed and a strong light, hopefully I'll be able to see what should go where on the board.

          Again, thanks for the schematic and the quick response!

          Tom

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          • #6
            https://support.fender.com/hc/en-us/articles/115002392666-SWR-Amp-Schematics

            https://support.fender.com/hc/en-us/article_attachments/115007781023/Workingman_s_2X10C.pdf

            https://support.fender.com/hc/en-us/article_attachments/115007781583/WorkingPro_2X10C.pdf 1)
            Last edited by vintagekiki; 10-30-2019, 01:00 AM. Reason: 1)
            Who does not know and knows that he does not know - teach him Confucius)
            Who knows and does not know that he knows - wake him Confucius)

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            • #7
              You know, as a technician you do have the right to decline a repair job.
              Education is what you're left with after you have forgotten what you have learned.

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              • #8
                This is a favor for a friend, or I'd have never started it.

                What's probably going to happen to it is when I can the the preamp section powered up, I'll scrap the power section and stick in one of those 100 watt preassembled TDA boards that you can get for about $8.

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                • #9
                  Thanks for the links, unfortunately, they all are much later versions than the one I've been blessed with.

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                  • #10
                    Thanks for the links, unfortunately, they are all much later TDA chip amps which the one I've been blessed with uses BJT transistors for output.

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                    • #11
                      SO how diffrent is your 1943/5200 version from the 2SC3281/2SA1302 version?
                      Attached Files
                      Education is what you're left with after you have forgotten what you have learned.

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                      • #12
                        Originally posted by HutchAmpMan View Post
                        Thanks for the links, unfortunately, they are all much later TDA chip amps which the one I've been blessed with uses BJT transistors for output
                        Attached links evidently you not viewed or not understand. It does not matter.
                        If it's not difficult specify your SWR model name from the front or back panel.

                        By the way Workingman 2X10C is not a TDA chip amps, it's designed in discrete technique.

                        https://www.talkbass.com/threads/workingmans-10-schematic.1428121/

                        Last edited by vintagekiki; 10-30-2019, 04:06 PM. Reason: 2)
                        Who does not know and knows that he does not know - teach him Confucius)
                        Who knows and does not know that he knows - wake him Confucius)

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                        • #13
                          kiki, the discrete transistor ones in your links are as far a I can tell, all of the quasi-comp type with the 2SC3284 transistors. The OP has a complementary circuit.
                          Education is what you're left with after you have forgotten what you have learned.

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                          • #14
                            Looking at both, the differences seem to center around the transistors with most everything pretty accurate.

                            Do you have a diagram for the power supply and preamp sections? I'll look more closely at them when I get of the doggy-dope the docs have me on for this sinus infection!

                            Thanks much!
                            Tom

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                            • #15
                              Thanks. One of these did provide additional information for me.

                              Best regards,
                              Tom

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