Why would a DECT Panasonic cordless phone keep losing the wirelesslink?

Discussion in 'Electronic Repair' started by Danny D'Amico, Jan 7, 2014.

  1. This makes sense.

    What I did today was I pulled the batteries out of the five handsets
    and pulled the power from the base, and let it sit that way all day.
    http://farm6.staticflickr.com/5506/11829276385_b88f6d65c7_o.gif

    Then, I performed the re-registration procedure as outlined on p27
    of this PDF:
    http://service.us.panasonic.com/OPERMANPDF/KXTG6431-MUL.PDF

    Here's just the Panasonic cordless phone re-registration procedure:
    http://farm8.staticflickr.com/7353/11829263895_ac761cd5cf_o.gif

    Hopefully, re-registering all five handsets may help with the
    problem of the Panasonic KX-TG6441 dropping calls after a while:
    http://farm8.staticflickr.com/7331/11829272305_f01a1c8679_o.gif

    I'll let you know what happens...
     
    Danny D'Amico, Jan 8, 2014
    #21
  2. This might actually be the problem!

    After removing all the batteries and allowing the handsets and base to sit
    for about five hours today ...
    http://farm6.staticflickr.com/5506/11829276385_b88f6d65c7_o.gif

    When I put the batteries back, I noticed that all five handsets said to
    "Charge for 7 Hours" ...
    http://farm8.staticflickr.com/7331/11829272305_f01a1c8679_o.gif

    So, I put them all on a 3.5 hour charger:
    http://farm8.staticflickr.com/7341/11829684174_606aa41376_o.gif

    And, when I put them back into the phone, they *still* said to
    charge for 7 hours!
    http://farm4.staticflickr.com/3756/11830061806_447da87566_o.gif

    So, maybe it's that simple - that the Ni-MH batteries, which are a
    few years old, are bad.

    One problem though, is that I put the new Ni-MH batteries that came
    with the charger in, after charging them on the charger, and the
    handsets *still* said to charge for 7 hours.

    So, something fishy is going on ... with the charge message on the
    handsets ... but I don't know what yet.
     
    Danny D'Amico, Jan 8, 2014
    #22
  3. Danny D'Amico, Jan 8, 2014
    #23
  4. That's a great suggestion Jeff.

    Maybe these other DECT phones in the same house:
    http://farm3.staticflickr.com/2873/11811729095_cafdd2467b_o.gif
    Are causing the problem with this DECT phone:
    http://farm4.staticflickr.com/3779/11811980883_f540a29bee_o.gif

    It might also be the batteries, although you can see in the previous
    photo that they are fully charged - yet - I charged them today off
    the Panasonic base:
    http://farm8.staticflickr.com/7341/11829684174_606aa41376_o.gif

    And, strangely, when I ran the registration procedure, they showed
    up as being discharged! ?????????
    http://farm8.staticflickr.com/7331/11829272305_f01a1c8679_o.gif

    So that makes absolutely no sense. I chalk it up to "confused
    electronics" at this point - because I can't imagine what happened
    to make a fully charged battery indicate almost discharged.

    Anyway, as a precaution, I ran the re-registration procedure,
    which is described on page 27 of this PDF:
    http://service.us.panasonic.com/OPERMANPDF/KXTG6431-MUL.PDF

    This is a snapshot of the re-registration procedure:
    http://farm8.staticflickr.com/7353/11829263895_ac761cd5cf_o.gif

    Since the menus don't show up until *after* you run the procedure,
    I post below sequential screenshots so others who run the registration
    procedure can see the cause and effect on the phones:

    Press LOCATOR on base 4 sec. Then press OK.
    http://farm4.staticflickr.com/3708/11829267845_c9363aba09_o.gif
    Call from Base:
    http://farm8.staticflickr.com/7392/11829686934_e1799e3098_o.gif
    Base regtr'ing
    http://farm8.staticflickr.com/7331/11829272305_f01a1c8679_o.gif
     
    Danny D'Amico, Jan 8, 2014
    #24
  5. Danny D'Amico

    mike Guest

    Since about zero percent of people are gonna do that, they might have
    concluded that a timer inside the device would determine
    that the device had charged all it could and the display was in
    terms of "do this" instead of any actual measurement, and be adequate to
    direct 99.9999% of users to perform the operation.

    Some people are "overthinkers" ;-)
    Hmmm...I resemble that remark.
     
    mike, Jan 8, 2014
    #25
  6. That might be the case Mike, because I know two things.

    The batteries were showing fully charged initially:
    http://farm4.staticflickr.com/3779/11811980883_f540a29bee_o.gif

    Then, I removed them and let the phone sit for a few hours:
    http://farm6.staticflickr.com/5506/11829276385_b88f6d65c7_o.gif

    When I then ran my first re-registration procedure, I was surprised
    to see that all five phones suddenly showed low battery indications:
    http://farm8.staticflickr.com/7331/11829272305_f01a1c8679_o.gif

    That made no sense because pulling the batteries and letting them
    sit disconnected for a few hours couldn't possibly have discharged
    them from full to near zero. But it was easy enough to charge them
    independently on a Ni-MH charger:
    http://farm8.staticflickr.com/7341/11829684174_606aa41376_o.gif

    Yet, I was again very surprised to see, after 3.5 hours on the
    charger (the lights stop blinking on the charger to indicate full
    charge) that, back in the handsets, they *still* said they were
    low on charge!
    http://farm4.staticflickr.com/3756/11830061806_447da87566_o.gif

    Something doesn't add up - but all five handsets acted the same
    way, even with the four new batteries from the charger put into
    two of the handsets.

    All five phones are now in their respective holders, and, I just
    checked the charge, and they went from one bar to three bars, so,
    that's just weird.

    It's almost as if they'll only charge from their Panasonic
    holders, and not from a separate non-Panasonic charger. But,
    that makes no sense - so - I really don't know what to make of
    this inconsistent data other than to ignore it.
     
    Danny D'Amico, Jan 8, 2014
    #26
  7. Don't you have a voltmeter? You shouldn't be depending on the base to inform
    you as to whether the batteries are actually being fully recharged.
     
    William Sommerwerck, Jan 8, 2014
    #27
  8. Part of the DECT standard is that a device listens before it transmits. If the
    channel is in use, it changes the channel. What happens when all channels are
    busy I have no idea.

    What you describe was the problem with the old 2.4gHz cordless phones. They
    just picked a channel and transmitted on it. The later ones were spread
    spectrum, so as far as WiFi was concerned, it interfered on ALL of channels.

    Or in plain English, when my upstairs neighbor's phone rang, my WiFi
    crashed.

    DCT phones work the same way as DECT phones, but on the 2.4gHz or 5.8gHz
    band. Again, what they do when all channels are busy I do not know.

    This is also why cell phones do not need to be licensed. They only
    transmit when asked to by a cell, which in most places is licensed.

    If for example, you were to bring a 1900mHz GSM phone to Europe, or a
    900/1800mHz EU GSM phone to the US, it won't start transmitting and
    interfere with whatever is using those frequencies.


    Geoff.
     
    Geoffrey S. Mendelson, Jan 8, 2014
    #28
  9. I was remiss in not mentioning that I tested the voltage with my fluke
    but the problem, as always, with testing open circuit no-load voltage
    is that without a load, a battery that tests good isn't necessarily good.

    However, all the handsets are now reading full bars in battery voltage,
    so, I'm inclined to assume that the battery-charge indicator on the
    handsets isn't really a voltage indicator - but some sort of integrator.

    The good news is that it hasn't happened since re-registration; but I also
    haven't been on the phone a lot either. I will report back in a few days
    to let you know if the problem is solved by the re-registration or not.
     
    Danny D'Amico, Jan 9, 2014
    #29
  10. Hi Jeff,
    The batteries are the original, and, they're all Ni-MH batteries.
    I noticed a set (white paint) was of a different amperage, so,
    I reassembled all the sets with like-amperage batteries (to
    prevent reverse voltage situations).

    I ran that from yesterday, Jeff, and they came back at 1.2 volts.
    So, I must tentatively conclude that the phone itself has a
    summative charging icon, where it might be "timed" in the charger,
    rather than checked at the battery.

    All five handsets, with the same batteries that read nearly dead
    after charging, now read full. I haven't extensively tested yet,
    but, all seems well now (tentative assessment).
    This might be the reason for the intermittence!

    What I *should* do is buy a DECT system with 9 handsets instead
    of two DECT systems for a total of 9 handsets.
     
    Danny D'Amico, Jan 10, 2014
    #30
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