Digital Clock Speeding Up (ie Gaining Time)

Discussion in 'Hobby Electronics' started by ghostgunna@mail.tpg.com.au, Oct 17, 2006.

  1. Guest

    Hi guys.

    I had a typical digital alarm clock for a few years. I noticed it
    started to report the time a few minutes fast. If I reset it the time
    would still go forward.

    I'm estimating it gains around a minute a week. This doesn't sound
    like much, but in 6 months the clock is half an hour ahead of the
    correct time.

    I thought the clock might be playing up because it is plugged in with a
    dozen other electrical devices (computer, home theatre etc). To
    confirm I plugged it into another socket on it's own in another room.
    The problem persisted so I threw it out.

    I got a new clock, and after a few months it is 20 mins ahead!

    Does anybody know the cause of this problem?

    Thanx 4 looking.
    , Oct 17, 2006
    #1
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  2. wrote:
    > Hi guys.
    >
    > I had a typical digital alarm clock for a few years. I noticed it
    > started to report the time a few minutes fast. If I reset it the time
    > would still go forward.
    >
    > I'm estimating it gains around a minute a week. This doesn't sound
    > like much, but in 6 months the clock is half an hour ahead of the
    > correct time.
    >
    > I thought the clock might be playing up because it is plugged in with a
    > dozen other electrical devices (computer, home theatre etc). To
    > confirm I plugged it into another socket on it's own in another room.
    > The problem persisted so I threw it out.
    >
    > I got a new clock, and after a few months it is 20 mins ahead!
    >
    > Does anybody know the cause of this problem?
    >
    > Thanx 4 looking.


    Most mains powered clocks derive their time form the 50Hz mains which
    is very accurate over a long time period. So your clocks are most
    likely picking up noise on the mains that is causing missing pulses or
    some such problem. Try adding a good mains filter to the clock, or just
    get a clock that does not rely on the 50Hz mains (usually the battery
    powered type).

    Dave :)
    David L. Jones, Oct 17, 2006
    #2
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  3. "David L. Jones" wrote


    Most mains powered clocks derive their time form the 50Hz mains which
    is very accurate over a long time period. So your clocks are most
    likely picking up noise on the mains that is causing missing pulses or
    some such problem.


    ****What???
    The clock is supposedly gaining time,not losing it!
    If it is missing "pulses" it will lose time!

    Brian Goldsmith
    Brian Goldsmith., Oct 17, 2006
    #3
  4. Brian Goldsmith. wrote:
    > "David L. Jones" wrote
    >
    >
    > Most mains powered clocks derive their time form the 50Hz mains which
    > is very accurate over a long time period. So your clocks are most
    > likely picking up noise on the mains that is causing missing pulses or
    > some such problem.
    >
    >
    > ****What???
    > The clock is supposedly gaining time,not losing it!
    > If it is missing "pulses" it will lose time!


    Oops, I meant "extra" pulses.

    Dave :)
    David L. Jones, Oct 17, 2006
    #4
  5. Phil Allison Guest

    <> wrote in message
    news:...



    ** Groper Alert !

    >
    > I had a typical digital alarm clock for a few years. I noticed it
    > started to report the time a few minutes fast. If I reset it the time
    > would still go forward.
    >
    > I'm estimating it gains around a minute a week. This doesn't sound
    > like much, but in 6 months the clock is half an hour ahead of the
    > correct time.
    >
    > I thought the clock might be playing up because it is plugged in with a
    > dozen other electrical devices (computer, home theatre etc). To
    > confirm I plugged it into another socket on it's own in another room.
    > The problem persisted so I threw it out.
    >
    > I got a new clock, and after a few months it is 20 mins ahead!
    >
    > Does anybody know the cause of this problem?
    >



    ** Likely the clock is not being powered by the AC mains supply on a 24 / 7
    basis.

    During the unpowered periods, the internal ( battery powered) time base
    oscillator takes over - and it runs a tad fast.

    Maybe the missus uses it power outlet for her vacuum cleaner or her steam
    iron or her ............




    ........ Phil
    Phil Allison, Oct 17, 2006
    #5
  6. Franc Zabkar Guest

    On 17 Oct 2006 01:12:55 -0700, put finger
    to keyboard and composed:

    >Hi guys.
    >
    >I had a typical digital alarm clock for a few years. I noticed it
    >started to report the time a few minutes fast. If I reset it the time
    >would still go forward.
    >
    >I'm estimating it gains around a minute a week. This doesn't sound
    >like much, but in 6 months the clock is half an hour ahead of the
    >correct time.
    >
    >I thought the clock might be playing up because it is plugged in with a
    >dozen other electrical devices (computer, home theatre etc). To
    >confirm I plugged it into another socket on it's own in another room.
    >The problem persisted so I threw it out.
    >
    >I got a new clock, and after a few months it is 20 mins ahead!
    >
    >Does anybody know the cause of this problem?
    >
    >Thanx 4 looking.


    There was a clock that featured in a thread at sci.electronics.repair
    some years ago that was affected by off-peak pulses or "remote-reading
    electrical power meters" or similar signals.

    http://groups.google.com/group/sci.electronics.repair/msg/159076a073f7a83e?hl=en&

    - Franc Zabkar
    --
    Please remove one 'i' from my address when replying by email.
    Franc Zabkar, Oct 18, 2006
    #6
  7. Guest

    Thanx 2 everyone who replied.

    When you say battery powered clocks, do you mean regular alkaline
    batteries? If so, wouldn't battery powered clocks lose time when the
    battery goes flat? And, wouldn't they go flat often?

    I don't think my clock has a battery at all. Whenever power is lost
    the clock is reset to 12:00.

    I noticed the clock on my microwave keeps the right time. Does that
    sound right if there is a problem with the power here?

    Is this the type of filter I should be looking at getting?
    http://www.dse.com.au/cgi-bin/dse.filereader?45362276029a446c2741c0a87f9c06f4 EN/catalogs/CTG0001024
    , Oct 18, 2006
    #7
  8. Phil Allison Guest

    <> wrote in message
    news:...

    >
    > When you say battery powered clocks...




    ** No one mentioned *any* such thing.

    You asinine Google Groups WANKER !!





    ....... . Phil
    Phil Allison, Oct 18, 2006
    #8
  9. wrote:
    > Thanx 2 everyone who replied.
    >
    > When you say battery powered clocks, do you mean regular alkaline
    > batteries? If so, wouldn't battery powered clocks lose time when the
    > battery goes flat? And, wouldn't they go flat often?


    No, an LCD display clock should last for years, just like a digtial
    watch.
    Something like this:
    http://www.dse.com.au/cgi-bin/dse.storefront/45369dd009708ca0273fc0a87f9c074e/Product/View/Y0621

    > I don't think my clock has a battery at all. Whenever power is lost
    > the clock is reset to 12:00.
    >
    > I noticed the clock on my microwave keeps the right time. Does that
    > sound right if there is a problem with the power here?


    That means it most likely has better designed circuitry (filtering)
    that gets pulses from the 50Hz mains. With your other clocks you have
    just been unlucky with a poorly designed product - twice.

    > Is this the type of filter I should be looking at getting?
    > http://www.dse.com.au/cgi-bin/dse.filereader?45362276029a446c2741c0a87f9c06f4 EN/catalogs/CTG0001024


    None of them seem to have the word "filter" in them, just "surge
    protection", that is different. Not that a filter is guaranteed to work
    anyway, cheaper to simply buy an LCD digital clock.

    Dave :)
    David L. Jones, Oct 18, 2006
    #9
  10. Phil Allison wrote:
    > <> wrote in message
    > news:...
    >
    > >
    > > When you say battery powered clocks...

    >
    >
    >
    > ** No one mentioned *any* such thing.


    I mentioned it Phil, in my first post.

    Dave :)
    David L. Jones, Oct 18, 2006
    #10
  11. Guest

    Thanx 4 your help Dave.

    I'll get myself an LCD clock.

    David L. Jones wrote:
    > wrote:
    > > Thanx 2 everyone who replied.
    > >
    > > When you say battery powered clocks, do you mean regular alkaline
    > > batteries? If so, wouldn't battery powered clocks lose time when the
    > > battery goes flat? And, wouldn't they go flat often?

    >
    > No, an LCD display clock should last for years, just like a digtial
    > watch.
    > Something like this:
    > http://www.dse.com.au/cgi-bin/dse.storefront/45369dd009708ca0273fc0a87f9c074e/Product/View/Y0621
    >
    > > I don't think my clock has a battery at all. Whenever power is lost
    > > the clock is reset to 12:00.
    > >
    > > I noticed the clock on my microwave keeps the right time. Does that
    > > sound right if there is a problem with the power here?

    >
    > That means it most likely has better designed circuitry (filtering)
    > that gets pulses from the 50Hz mains. With your other clocks you have
    > just been unlucky with a poorly designed product - twice.
    >
    > > Is this the type of filter I should be looking at getting?
    > > http://www.dse.com.au/cgi-bin/dse.filereader?45362276029a446c2741c0a87f9c06f4 EN/catalogs/CTG0001024

    >
    > None of them seem to have the word "filter" in them, just "surge
    > protection", that is different. Not that a filter is guaranteed to work
    > anyway, cheaper to simply buy an LCD digital clock.
    >
    > Dave :)
    , Oct 26, 2006
    #11
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