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IC needed (out of SONY unit)

Discussion in 'Hobby Electronics' started by Rudolf Ladyzhenskii, May 4, 2004.

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  1. Hi, all

    I am after an IC STIL04-P5. It is "inrush current limiter" and came out of
    SONY laptop power supply.

    Speedy Spares do not carry parts for laptops and this IC did no t came up on
    the computer. Call to SONY Australia revealed that they only sell complete
    units (what a surprise!).

    Anyway, I am after this IC or SONY part number for it. Can anyone help me?

  2. Ross Herbert

    Ross Herbert Guest

    Don't know where to get one but it is a current ST product
  3. I know it is a current product.

    I called Australian distributors for ST -- Arrow and Braemac. They do not
    have listing on their system.
    Farnell and RS do not have it either.

  4. Phil Allison

    Phil Allison Guest

    ** Time to revert to steam age technology - fit an NTC thermistor in
    place of that start up resistor !!!

    ........... Phil
  5. Ross Herbert

    Ross Herbert Guest

    Yep, replace the input R with a normal NTC inrush limiter as PA
  6. Did you actually took time to look at the datasheet before suggesting an NTC

    A short extract from a datasheet:

  7. Sorry, finger slipped.

    Here is the extract:

    STILxx is a circuit combining two unidirectional switches for use in a smart
    configuration of a primary rectification bridge, mixing diode rectification
    and SCR. We call this circuit a Half Controlled Rectifier Bridge (HCRB).

  8. Phil Allison

    Phil Allison Guest

    ** Yes - did you ?????

    ............ Phil
  9. Phil Allison

    Phil Allison Guest

    ** If you look at the basic circuit and description of operation you will
    see that all the damn thing really does is to bypass the start resistor in a
    controlled way after switch on.

    An NTC thermistor will do the same thing by dropping its value as it

    ............ Phil
  10. Hi,

    There must be a reason for the IC to be there in the first place instead of
    cheaper NTC thermistor.

    Beside, I am not going to modify customer equipment.

  11. Phil Allison

    Phil Allison Guest

    ** There are advantages in performance - like I said, NTC thermistors are
    an old technology.

    ** Then you are one of those incompetent techs that re-installs all the
    faults when doing repairs.

    ................ Phil
  12. Ross Herbert

    Ross Herbert Guest

    If you have a look at AN1600 on the ST website it explains why the
    STIL is supposedly better.
    I don't think any modification would be necessary other than swapping
    Ri for the NTC. Instead of working as a half bridge controlled
    rectifier it would then operate as a normal full bridge. It shouldn't
    be too hard to verify if this is the case.

    Ross H
  13. It all sounds fine, except the legal implication if something goes wrong
    (even if this particular part in not the problem).
    By modifying it, I effectively void any compliance testing unit went
    through, etc, etc, etc...

    While I would go ahead and try it in my own unit, I would only use original
    parts in customer equipment.

  14. Phil Allison

    Phil Allison Guest

    ** NTC thermistors are used in massive number of appliances, in the AC
    supply line and elsewhere.

    Wonder how they manage to comply ???

    ** So you are one of those incompetent techs that re-installs the same
    fault - every time.

    You never up-grade a component, you never use an alternative, you never
    buy the dubious stuff WES sells - you ONLY use "official" spares as
    supplied by the equipment maker etc etc.

    How anal.

    ............ Phil
  15. Ross Herbert

    Ross Herbert Guest

    I can understand your reluctance to alter the original circuitry but
    if you explain the alternative to the customer he might agree. As I
    see it if you can't source the original component the only option is
    to import one at great expense to the customer or do as suggested by
    PA and myself. It will have to be the customer's decision which you
    should document.
  16. It may be customer decision, but my liability.

    I'd rather protect myself and lose this repair.

  17. Phil Allison

    Phil Allison Guest

    ** Not in appliance repairs - now maybe if you fixed Bell helicopters
    for a living ........

    ** Upgrading parts as needed and making proper substitutes for common parts
    (or where exact replacements are not available) is a major part of a
    repair's job and skills.

    ** Firies can often locate the source of a fire - ie the location where
    is must have started. If the remains of a TV is sitting in that same
    location, plugged in to the AC supply, they draw the obvious conclusion.

    ................ Phil
  18. Franc Zabkar

    Franc Zabkar Guest

    I know you are loathe to implement design changes, but perhaps the
    original design is flawed. After all, the part *did* fail.

    FWIW, some NEC multisync monitors used an inrush current limiting
    resistor paralleled by an SCR. The SCR was made to turn on, and
    therefore shunt the resistor, only when the filter cap had charged to
    an appropriate level.

    - Franc Zabkar
  19. No, I do not know anyone who was sued, but I do not want to be first one

    No one will know until something happens (fire or person gets slectricuted,
    etc.). Then investigation will show a modified unit, even if this mod is not
    the cause. (I am probably being paranoid here).

    Being an engineer, I know that when ANY part in the power supply of the unit
    is changed, it must go through approval process. Unit was tested for
    electrical compliance as well for EMI/EMC and any change can affct the

    I do not have problems using substitute parts, although I prefer originals,
    but in this case we are talking about modifying the circuit.

  20. Phil Allison

    Phil Allison Guest

    ** Any substitute of one part for another **is** a modification - so
    ALL repairs where parts are changed involves modification. If the new
    part is not up to performing the job, is of substandard manufacture or any
    way is not as suitable as the original then an early failure can result.
    This possibility is an inherent risk in doing repair work.

    Equipment manufactures have ***exactly *** the same problem - they have
    no idea what they are sending out he factory door is any damn good or not
    since THEY did not themselves make the bloody components.

    If you are nervous about making changes to something because you fear
    mysterious, unforeseeable consequences - then by all means don't.

    But please do not tell others with more technical insight that you they are
    wrong to do so.

    .............. Phil
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