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PT secondary windings?

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  • PT secondary windings?

    Hi all,

    This is probably more "guessing" than anything, and I have no immediate plans for this tranny; just curious for future reference. I got an old projector for peanuts and parts since it had tubes. I'm not saying any more about it, cuz I checked ebay AFTER I got it into pieces, and, D'oh! Check used prices BEFORE disassembly! Anyway I have a PT here.

    Tubes powered:
    ECC83 X2
    EL84 X2
    EF86 X2
    ECL82 X1
    EM84 X1
    extra projector bulbs...

    My question is, I've got 3 different 6V secondaries & a 12V. These are all unloaded measurements. The 6V ones break down like this:
    #1 6.5VAC, 2ohm end to end
    #2 6.7VAC, 0.6ohm " " "
    #3 6.4VAC CT, 2ohm " " "

    Is it safe for me to conclude that #2 is for the EL84s given the higher voltage (expecting more of a load & voltage drop) and the lower resistance (thicker wire, carries more current)?
    I'd use #1 to power the EF86s or other small tubes, and #3 for ECC83s since it's got a CT.
    I'm going to use less tubes than what it came with, won't chance a tube recto (even a 9-pin). The 12V I could use as a fixed bias supply for EL84s, no?
    Meter used to measure is a Fluke 112, not lab quality, but certainly not cheap. I know that meters can be unreliable at very low resistances... But if this tranny burns up, I'm not exactly out anything for it. Just wondering if my "theory" is sound?

    I know... next time draw the picture first! But this thing was packed so tight I couldn't follow anything. And the nice OT & Mullards were worth the price.

    Thanks,
    Justin
    "Wow it's red! That doesn't look like the standard Marshall red. It's more like hooker lipstick/clown nose/poodle pecker red." - Chuck H. -
    "Of course that means playing **LOUD** , best but useless solution to modern sissy snowflake players." - J.M. Fahey -
    "All I ever managed to do with that amp was... kill small rodents within a 50 yard radius of my practice building." - Tone Meister -

  • #2
    Personally, I would try to find a schematic (or draw one if you can if possible). Count the filaments on each string.

    Comment


    • #3
      I think that is a fine idea. You might find that schematic and answer all your questions.
      Education is what you're left with after you have forgotten what you have learned.

      Comment


      • #4
        Thanks guys, I'd find a schemo if I could, but it's been a few years, I took no notes on model, and it's in a zillion little pieces! Lesson learned when I checked ebay & found one going for $400... and I take notes on every bit of junk I get now...

        Justin
        "Wow it's red! That doesn't look like the standard Marshall red. It's more like hooker lipstick/clown nose/poodle pecker red." - Chuck H. -
        "Of course that means playing **LOUD** , best but useless solution to modern sissy snowflake players." - J.M. Fahey -
        "All I ever managed to do with that amp was... kill small rodents within a 50 yard radius of my practice building." - Tone Meister -

        Comment


        • #5
          Originally posted by Justin Thomas View Post
          Thanks guys, I'd find a schemo if I could, but it's been a few years, I took no notes on model, and it's in a zillion little pieces! Lesson learned when I checked ebay & found one going for $400... and I take notes on every bit of junk I get now...

          Justin
          If you found one on eBay, did it list the model number? Have you tried google images? Search for brand and function.

          Comment


          • #6
            Or even google the part number on the transformer.
            Education is what you're left with after you have forgotten what you have learned.

            Comment


            • #7
              ^this, if you can't remember what make and model it was. However, I've had one heck of a time identifying some of the transformers I got twenty plus years ago. If the company uses in-house numbers, good luck. If they have the standard six digit code like "138813" (one of my PTs) you can at least tell the manufacturer and approximate date. Here's a list of codes that may give you a starting point.
              Attached Files
              --Jim


              He's like a new set of strings... he just needs to be stretched a bit.

              Comment


              • #8
                I did some googling last night, well, Binging... looking at pics, seems to have been a Cine Film 2000. No schematics I could find, though. Do any of these markings mean anything to anyone?

                B71613- A74- A 2
                ( Zub. Bv. 726074/32/1 )
                § Ausg. V1

                On side of lams, smudged: B oeor 48 (??? reading as best I can)
                On frame:
                3V1 33
                I do remember it being Pre-Berlin Wall...
                I guess I'll just have to try it & see... I got a 2xEL84-16ohm OT & good tubes out of it already. All Mullards except 1 Siemens EL84 & an RCA 6BQ5.

                Justin
                "Wow it's red! That doesn't look like the standard Marshall red. It's more like hooker lipstick/clown nose/poodle pecker red." - Chuck H. -
                "Of course that means playing **LOUD** , best but useless solution to modern sissy snowflake players." - J.M. Fahey -
                "All I ever managed to do with that amp was... kill small rodents within a 50 yard radius of my practice building." - Tone Meister -

                Comment


                • #9
                  Give these guys a call Monday and see if they are the original maker of the transformer:

                  Prestec Electronics, Ltd - Ottawa Canada

                  This is a link to more manufacturer codes:

                  http://www.davelevasseur.com/1994%20...ode%20Book.pdf
                  --Jim


                  He's like a new set of strings... he just needs to be stretched a bit.

                  Comment

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