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Circuit diagram 4 CF by OSRAM

Discussion in 'Home Power and Microgeneration' started by A+, Oct 8, 2003.

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  1. A+

    A+ Guest

    Bought 10 of these which supposed to save me $$$ for the next ten
    years (warranty) except five already fell like dead flies after one year.
    Read in a consumer report that they normally fail after 1200 switching
    (average one year usage).
    So much for my savings. Could have done better with the cheapest
    incandescent light bulbs.

    I'd like to check what component failed ?
    Does anyone have a circuit diagram ?

  2. N9WOS

    N9WOS Guest

    I have never been able to find a diagram for any CF lights.
    But the circuit is pretty simple.

    And trouble shooting it is easy.

    From input to light.

    bridge rectifier.
    Either a bridge (4 diode) feeding
    a single cap at 170V
    Or a full wave Voltage doubler feeding
    two caps for a total of 340V across both caps.

    That is feed into a chopper which is driven by two
    NPN, PNP or fet transistors.
    The transformer that they are driving uses one winding
    in the resonant mode.

    The feedback is via a ferrite core on the output of the resonant
    transformer with windings to feed the gates of the transistors.
    Or via small caps and resistors to achieve a phase lag
    to drive the gates.

    The output of that is feed to the lamp with a cap or
    thermistor to pull current across the filaments to heat them.
    The CF lights with the thermistor is the ones that take a few
    seconds or minute to come to full brightness.
  3. daestrom

    daestrom Guest

    Sorry to hear of your troubles. I've had some GE cf's installed since I
    moved into my house (3 1/2 years now), and the bathroom and kitchen see a
    lot of switching (still have to nag everyone to turn off lights when they're

    What brand name do you have? Perhaps a brand defect??

    Haven't taken any of mine apart (haven't failed yet ;-)

  4. It's not as easy as that unless the failure has left smoke. A typical
    failure in this sort of circuit is to have a high voltage electrolytic
    capacitor short out. This usually smokes. Another typical is an open circuit
    in a solder joint or in one of the fly wire bonds in any of the plastic
    parts. This may be hard to detect without disordering all the parts and it
    may even induce a secondary failure that does produce smoke and hides the
    primary cause. The last major failure mechanism in all the high voltage
    semiconductors is to pop the junction. This will look like a short and
    usually leave a smoke trail.
  5. To move away from the original question a bit, does anyone manufacture
    CF lamps designed to run on 6 or 12 volts, or is it practical to
    modify CFs to run on battery juice. It occurred to me that one could
    make a very handy battery-powered floodlight by mounting a CF in an
    old auto headlight reflector.

    I winder if the tube of a CF would light using the electronics package
    of a 12 volt linear fluorescent lamp as used in RVs, etc?

    Gordon Richmond
  6. Vaughn

    Vaughn Guest

    They are manufactured by the Feit company (part number BPESL13T/M12).
    Googling may provide a source, but I got mine at West Marine, their model
    number is 2675106 and the price was $14.99. I have been using two of them
    for yard lights off of my PV system for well over a year now. That means
    that conservatively they have 370-some starts and 1500 hours and are still
    going strong. Be sure to observe proper polarity (the package is not clear
    on this vital detail), the tip is positive!

  7. A+

    A+ Guest

    PS: My ISP does not allow attachment ???
    So no picture attached. If you want, I will be happy to email it to
    you directly.

    OSRAM is Made in Germany. I believe it is SIEMENS subsidiary.
    The description provided by N9WOS above is close but not enough.
    I attached a picture shown one side as they have several ceramic capacitors
    on the other side too.

    BTW no signs of burns at all !!!


    Yes BIG time for Made in Germany ... The ones Made in China (sold by IKEA)
    haven't failed yet !!!
  8. N9WOS

    N9WOS Guest

    PS: My ISP does not allow attachment ???
    Could you please send me a pic of both sides?
    I would like to see what the board looks like.
    Brain food is always a good thing! :)

    Just remove the "nobug" from my Email address.
  9. Many thanks,

    Gordon Richmond
  10. N9WOS

    N9WOS Guest

    I can tell a few thing from that pic.

    It uses a full wave bridge to feed one cap at 170V

    It uses a center tapped secondary winding in the transformer to drive the

    It uses capacitors across the filaments to provide heating current.

    Question, did the safety fuse blow on them?

    The capacitors across the filaments look kinda small for that application.
    And they look like metal film caps with a clear plastic case.
    If they are then the dark area in the middle is a sign of overheating.

    Check them to see if they are ok.
    If they shorted out, then it probably burnt the filaments in two.
    Disconnect the lamp from the board and see if the filaments are
    still intact.

    IF the safety fuse is blowed, then check the transistors, filter cap, and
  11. A+

    A+ Guest


    * I see NO fuse on board *
    * I'd say half of them are shorted out on back *
    * Both tube filament show open circuit *
    * I see NO fuse anywhere *
  12. N9WOS

    N9WOS Guest

    Question, did the safety fuse blow on them?
    ALL CF lights have a fuse in them.(In the USA.)
    It is usually located near the Edison base,
    where the power comes in.
    It is usually in one of the wires coming from
    the base, and going to the board.
    It is usually not mounted on the board.
    If you are talking about the ceramic surface mount capacitors
    on the bottom of the board, I would say they are still in good
    The only ones that normally go out is the ones across the filaments
    They are subjected to 100V at 50Khz or higher.
    The internal heating from the ac current is what makes them fail.

    Then the caps across the filaments most likely went out.
    And the bulb is toast.
    So the easiest way to see what made it fail is just
    unsolder everything from the board and test the components
    one by one.
    When you find the bad ones, then you know what failed.
    Then take the rest of the good components and put them
    up for future projects. :)

    There is always a fuse in them, it is required by law.(In the USA)
    To many of them have went up in flames, so they
    forced them to put the fuses in the lights.
    Hold it........(thinks for a second)
    That is a US law, so they may not require them in france,
    or where ever you are located.
    I keep thinking everyone is from the US,
    Forgive me :-(
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