Announcement

Collapse
No announcement yet.

Fender Pro Junior

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Fender Pro Junior

    Hi all.Sorry for my English if it is not perfect.
    I have a problem with my Fender Pro Junior. The power Transformer is broken and i can't find an new one. Could you tell me what is the voltage on the secondary winding?so i can order a generic one with this specifc.
    I have found this schematic on internet

    http://www.webphix.com/schematic%20h...mps/pro_jr.pdf

    But i'm not sure it is correct because on the schematic i see on the secondary winding 132 Vac but i think is too low to have more than 300 Vdc on [TP24]. in fact the specific value is 132*1.41=186 and it is different from 319 Vdc.
    Can someone help me?
    Thanks for your attention,I hope in your reply.

  • #2
    --------------------------------------------------------------------------------

    Link: Guitar Nucleus Guitar Parts - Fender Amp Parts
    GN49967PT-FEN Power Transformer Fender Replacement 330-0-330 V 120 ma
    Fender Original Blues Junior Power Transformer. 15 watts. Equivalent to #049967.

    Primary: 117 volt, 60 Hz
    Secondary: 330VDC, 68 mA after rectification
    Filament winding 1: 6.6 VAC, 2.6 A
    Mounting Centers: 2" x 2" horizontal
    Weight: 2.6 lbs


    $77.95

    Comment


    • #3
      Thank you very much for the answer.
      So the blues junior and the pro junior have the same power?
      can i buy the blues junior transformer for the pro junior without problems?

      Comment


      • #4
        http://music-electronics-forum.com/t19462/
        It should be o/k.
        If there is a 15 volt winding , tape it off.
        EDIT: the 15 volt winding is BRN/ BRN CP16 & CP17 on the schematic.
        I have attached the Blues Jr schematic so you can compare the two amps.
        Attached Files
        Last edited by Jazz P Bass; 07-27-2011, 07:33 PM.

        Comment


        • #5
          Better price: Fender Power Transformer, Blues Junior

          Comment


          • #6
            thank you very much for the answer and for links.
            The only problem is that i live in Italy so i have to buy a transformer with primary windin at 230 Volt.
            So i have to find a site with this kind of transformer
            do you know some one?

            Comment


            • #7
              The Fender part# is 049968.
              (look on the Blues Jr schematic)
              I do not about aftermarket availability.

              Comment


              • #8
                The Pro Jr uses a different PT (export p/n 041783) with a slightly lower secondary voltage than the Blues Jr. If you're trying to find a generic replacement, note that it uses a bridge rectifier, so you'll be looking at a ~225VAC secondary.

                Comment


                • #9
                  Originally posted by ThermionicScott View Post
                  If you're trying to find a generic replacement, note that it uses a bridge rectifier, so you'll be looking at a ~225VAC secondary.
                  I have done a simulation with Spice but if i use 225 Vac at the secondary winding i have not 320 Vdc where i need it after rectification.
                  I have to use a secondary winding at 330Vac in the simulation to have 320 Vdc.
                  Is it normal?

                  Comment


                  • #10
                    That statement does not compute.
                    330Vac should not drop when rectified to Vdc.
                    Vac x 1.4= Vdc.
                    The final Vdc will depend on the rectifier topology & filter caps.

                    Comment


                    • #11
                      This is the result of the simulation.
                      Could you take a look?

                      ProJr_Transformer.pdf

                      I used a transformer with 330Vdc on the secondary winding and i have correct value.
                      the simulation is wrong?
                      I did it at the university

                      Comment


                      • #12
                        Simulations are nice & all.
                        As I have never done one, may I suggest you breadboard the circuit.
                        Then take your voltage readings.

                        Comment


                        • #13
                          Originally posted by Rebel View Post
                          I used a transformer with 330Vdc on the secondary winding and i have correct value.
                          the simulation is wrong?
                          Yes. A power transformer will have VAC (in RMS) on the secondary. Simulations are great, but they're not reality.

                          - Scott

                          Comment


                          • #14
                            thanks to all for your answers.
                            I tested the power transformer yesterday and it seems working properly.
                            instead of 320Vdc on the secondary winding i have 350Vdc on circuit but it is only a little differece that components could be support.
                            Next time i will not follow the simulation program but only the old rule Vac*1.41=Vdc
                            thaks to all again!!!

                            Comment

                            Working...
                            X