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Hang after power failure

Discussion in 'Cisco/Linksys Wireless Routers' started by tin68, Aug 12, 2008.

  1. tin68

    tin68 Addicted to LI Member

    I am using two WRT54GL with Tomato firmware - actually version 1.21.

    Two times I had a little problem with this router - besides that I am very satisfied.

    After a very short power failure (during a thunderstorm) the router didn't boot again - it was hanging an the Power LED was blinking all the time and a connection to it wasn't possible. The first time I was at home so I could reboot it again. But the second time I wasn't at home - but because the connection to the Internet was broken I wasn't able to reboot it by remote.

    Any hints?

  2. HennieM

    HennieM Network Guru Member

    This happens when the power to the router just dips enough not to let the electronics go off (the incoming voltage goes to perhaps 4V or so), and then the power comes back. This is an undefined state for the electronics, so some electronics are still "up", while other parts are "down". The router therefore sort of shuts down, but does not power off, so it does not go through the boot sequence.

    It's a hardware phenomena - nothing to do with Tomato.

    Some suggestions [(2) and (3) have complexities, so gather some more info before trying them]:
    1) Put the router on a UPS.
    2) Expand (significantly) the capacitors in the wall power supply.
    3) Add a 12V battery between the wall supply and the router.

    4) Get a lightning detector, build a robot, and have the robot pull the power plug of the router when it detects lightning.. ;-)
    That's a joke, but you could build (or have build) a little box that sits between the wall power supply and the router, which would shut off the power to the router completely when the voltage drops to below say 9V or so, and then delay re-powering by a couple of seconds. This way the router will shut down completely when the power dips, and then start up cold.

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