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Sim800L Net Light flashings

Discussion in 'General Electronics Chat' started by Wp100, Sep 18, 2017.

  1. Wp100

    Wp100 Active Member

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    Hi,

    Have one of these Sim800L Coreboards working fine and ordered another board recently.

    However when the new board is powered up, the netlight flashes as if its searching, eg about once per second for 13 times, then pauses for 3 seconds then resumes for 13 flashes again etc.

    I can talk to it with AT commands ok, but AT+CSQ, signal strength, shows 0,0 instead of 30,0

    Cannot find any reference to this sequence of flashing , though not sure why it stops searching after 13 flashes ? the other board can take 20 flashes before it connects ok.

    Does anyone know if these 13 flashes are a known message or just got a bad board ?

    thanks


    000416.jpg
     
  2. Diver300

    Diver300 Well-Known Member

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    It looks like it is trying to connect to a network, failing, turning off, and then turning back on and trying again.

    The power supply needs to be able to meet the 2 A peak current, and a power supply issue can give the behaviour described.
     
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  3. Wp100

    Wp100 Active Member

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    Thanks, but its on a 5A variable psu at 4.00v

    Now seen some posts suggesting the problem may be in the AT+CBAND default settings, so just trying a variation on them.....


    Edit,

    Have compared the settings of the older working Sim800L with the new one and have got the CBAND as EGSM_MODE,ALL_BAND and the COPS shows "02" .

    Have also tried changing to all of the different CBAND modes, this does affect the flashing, some settings a few flashes lower, other setting it flashes all the time, but seems it does not want to log on.

    The Sim card is in the right way around , the 4v linear psu is good, the Arduino lines are correctly resistored exactly the same as the working old Sim800L, but something still not right ??
     
    Last edited: Sep 18, 2017
  4. dave

    Dave New Member

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  5. Wp100

    Wp100 Active Member

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    Hi again,

    My old Sim900 module and the Sim800L purchased last year both work fine on my Tesco(o2) Payg sim card, but on this new Sim800L, which looks identical to the older one, it does not work, as above.

    Just tried a Virgin(EE) Sim card and the new 800L locks on to the network straight away !

    The problem is no idea why, but can only assume some setting on the firmware for the 800L, plus need to use a Sim card like the Tesco one that allows a top up to be carried over for months when inactive, unlike most bundles which need monthly top up.

    Any suggestion of what is stopping this new 800L from using the Tesco (o2) sim ?

    thanks
     
  6. Diver300

    Diver300 Well-Known Member

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    Does it work on an O2 SIM? Could it be that the SIM doesn't tell the module which network to work on?
     

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