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LOPT ???

Discussion in 'Electronic Repair' started by Tim Kettring, Apr 28, 2004.

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  1. Tim Kettring

    Tim Kettring Guest

    Whats a LOPT ? Line OutPut Transformer ???

  2. Joe Rongen

    Joe Rongen Guest

    X-no-archive: yes

    Tim, that is the British way of writing:
    horizontal output transformer or HOT.

    Some people have suggested that this
    sort of thing happens, because the British
    have been living on a small island way too long. :)
  3. Bob Parker

    Bob Parker Guest

    Aren't they called an "FBT" for FlyBack Transformer in the
    USA/Canada? Not being pedantic, but I was under the impression that
    "HOT" stands for Horizontal Output Transistor.
    That was my understanding, as a denizen of far-away upside-down
    Australia where we use the British terms terms too. But our island is
    much bigger and warmer than theirs is. :)

  4. Ken Weitzel

    Ken Weitzel Guest

    Greetings from one colony to another :)

    Here, it's a flyback. Mostly because that's what you
    tend to do when you grab ahold of one :)

    But then I'm old, long retired. Perhaps the younger
    folks have re-named them :) Heck, I don't even
    know what ESR or ESB or whatever they're referring
    to when they talk about electrolytics is :(

    And your little country sure isn't bigger than
    ours is :) Might be warmer now, but won't be
    in another month or so :)

    Take care.

  5. Art

    Art Guest

    Seems that this has been addressed before in the N/G. Been doing service
    since before the 3A3 became common. Always called the flippin things Flyback
    Transformers or High Voltage Transformers. Then Integrated High Voltage
    Transformers seemed to become the rage?? Especially when developers found
    out how to encase the Tripler within the case of the Flybacks. Having seen
    many schematics from the European Continent I became amused at the fact that
    the engineers termed them Line OutPut Transformers until I review some
    transmitter designs, which also called the main output power transformer
    device a LOPT. Kind'a use the terms interchangeably now, as do most of the
    service and parts personnel we deal with on a daily basis. Only time it
    causes a bit of confusions when a specific company wants it called by the
    name they have in their parts list, preferable with the correct part number.
    IMHO this discussion will go on 'al infunatum'; the more globalization that
    takes place in this industry the more we need to be aware of the different
    terms for items, and applications of the same Cheers to all both on the B/I
    & Down Under!! Maybe a pint of "Guinness" or six pack of "Fosters" will tend
    to quite all the row?? Eh
  6. Joe Rongen

    Joe Rongen Guest

    X-no-archive: yes

    Looking at the literature in Canada from different manufacturers
    (that I've seen) one can read more often "horizontal output
    transformer" than flyback transformer or FB for short.
    Yes, you are right "HOT" can also indicate other things
    including the side, carrying 120 VAC in electronics.
    Nice to hear from you... hang in there! :)
  7. But then I'm old, long retired. Perhaps the younger
    I guess that in the good old days the failure rate of electrolytics wasn't
    as high as it is today.
  8. John Miller

    John Miller Guest

    Maybe worse. But the failure mechanism wasn't as well understood, and often
    we'd make the symptoms go away by bridging a capacitor with a substitute,
    then change it out and go on our way, without ever realizing there was such
    a thing as ESR.
  9. Ken Weitzel

    Ken Weitzel Guest


    Or in the case of the old can types, just bridge
    the bad section and leave it :)

    Memories.... the old "joke" back then was:

    "Do you know why my radio hums?"

    "Because it doesn't know the words"

    What *does* ESR or ESB stand for?

    Take care.

  10. Bob Parker

    Bob Parker Guest

    ESR is short for Equivalent Series Resistance, that annoying
    characteristic of electrolytic caps to behave as though they have a
    substantial resistor in series with them.
    If you go to Doug Jones' Capacitor Wizard website at, there's a lot of info there about this

  11. exray

    exray Guest

    Aargh....that old-time practice killed a lot of power transformers
    because of the leakage (load) presented by the old cap.

  12. BWL

    BWL Guest

    However, there are sets (mostly rear projection) with both high voltage AND
    horizontal output transformers. I like those terms, since there's no confusion
    about what each one does...
  13. Ken Weitzel

    Ken Weitzel Guest

    Thanks, Bob. I appreciate it. Old, long retired,
    strokes took me out of the picture for a loooong time,
    but it's still nice to keep up a little. :)

    Thanks again, and take care.

  14. Ken Weitzel

    Ken Weitzel Guest

    Hi Bill...

    Yeppers, but we knew no better...

    And it was difficult to heat the twisted soldered
    to a chassis lugs to remove them... :)

    Take care.

  15. Bob Parker

    Bob Parker Guest

    Glad to be of some kind of assistance Ken. :) I'm not that young
    myself any more!

    Best wishes,
  16. L. Fiar

    L. Fiar Guest

    Here in the UK, they have been known as a LOPT (Line OutPut Transformer) for
    many years. The term Flyback Transformer is now more often used here
    Some years back, Thorn used a system known as SYCLOPS - Synchronous
    Converter and Line OutPut Stage.
    What a name.

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