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  • Help with ID of a power transformer...

    This PT is new/old. I installed it in a Tweed Deluxe chassis with a Mojo 768 OT but I never finished the build, stuff happened and I am getting back to it after almost 10 years. The board is all wired sockets in, almost everything done except wiring the transformers. I tried to understand using a zener diode to drop the voltage but was not sure about it, then things happened, we moved, etc etc... now I do not know what the PT is. It has numbers but no name and I cannot find a spec sheet nor anything online when searching the numbers. It is a black bell PT. The numbers are:
    1155-1017
    6050215

    The wires are: 1 black; 1 black with white; one orange; 2 x red; 1 red with white; 2 x green; 1 green with white; 2 yellow; 1 brown; 1 brown with white. For some reason I had the brown and black twisted together... I need to find my schematics and layouts...

    I am sure it is a Mojo PT because the number layout is identical to the 768 OT, but with different numbers... so what I really need is a spec sheet AND... since I am using a Bandmaster OT should I just go with Fender wiring or should I add the zener diode? I mean, I can always build another amp. I am not that concerned that this amp has the voltage of an original 5E3... as lonClick image for larger version

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ID:	868174g as I am not doing something that will destroy the power tubes... I am open to using other tubes. Also, I think my OT is for an 8ohm speaker but I have six 12s still in boxes, a blue bell, a signature Alnico, and four Carvin V-30 clones I bought when they were blowing them out for 20 bucks each... and I can buy another speaker if I need it. I also have two 769 OTs, since this one is not yet wired.
    I am open to suggestions and hope someone has a source for a spec sheet for this PT. I don't like frying transformers, lol. I have other pics of the amp if you want to see them...
    I would LOVE any help on the use of the zener diode... frankly, I have forgotten where it was to be wired into the circuit and now they make PTs with lower voltage so you don't need it... at this point I am about convinced to forget it and see how it goes... my only worry is the tubes, but I can use 5881s or something else if it will be better. help...

    Thanks! I got great help here on trouble shooting a SF Champ.

    Julien

  • #2
    So if you are convinced this is a Mojo transformer, contact Mojo with the numbers and ask them.
    Education is what you're left with after you have forgotten what you have learned.

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    • #3
      Other pics... Click image for larger version

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      Click image for larger version

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      Click image for larger version

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      Zener and a couple of resistors.
      Click image for larger version

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      I am to the point of wiring in the transformers, installing the jacks, and fuse... and maybe the zener. Then into cab!

      Thanks!

      J

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      • #4
        I did, they are closed due to weather so I thought maybe someone would know.. and since I am snowed in I thought I'd work on it tomorrow if I can figure it out. I guess I can just wire it without the zener, I never was really happy about that anyway.. as long as I am not building something that will eat tubes, but I don't really think it will. I just think it will be a HOT Deluxe... I hope. Asking never hurts though and you guys know a lot more than I do. I am really rusty.

        J

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        • #5
          [QUOTE=jbow;332404]This PT is new/old. I installed it in a Tweed Deluxe chassis with a Mojo 768 OT but I

          The wires are: 1 black; 1 black with white; one orange; 2 x red; 1 red with white; 2 x green; 1 green with white; 2 yellow; 1 brown; 1 brown with white. For some reason I had the brown and black twisted together... I need to find my schematics and layouts...

          Black and white wires are usually 120VAC input.

          Two red are usually for rectifier
          Two yellow are also for rectifier

          Red/white probably bias supply (would be in the <60VAC range).

          That's off the top of my head, based on experience with Fender transformers. Browns, orange, are new color for PTs for me

          Comment


          • #6
            Your transformer may have been made by Lenco Electronics Inc. Their EIA code is 605.
            They *may* have made this for Mojotone although currently I think they use Heyboer transformers.

            If Mojotone doesn't come through perhaps you might want to contact Lenco.

            Lenco Electronics | Custom Transformers | Ferroresonant Transformers | DC Filter Inductors | Constant Voltage Transformers | Isolation Transformers | Three Phase Transformers | Power Transformers | Auto Transformers

            SG

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