Shutdown feature, does it turn off completely?

Discussion in 'Tomato Firmware' started by ImGeo, Nov 20, 2009.

  1. ImGeo

    ImGeo Addicted to LI Member

    I've been using the shutdown feature via remote access, and notice that it doesn't seem to shutdown complete. After being shutdown, the WAN light blinks continually (the other lights are off). I've done lots of searching, but am not sure what the showdown feature is really supposed to do.

    And along those lines, how should I turn it back on? I've been unplugging and replugging the power.

  2. Planiwa

    Planiwa Network Guru Member

    Shutdown does not power down.
    It only makes it safe to power down.
    Since there is no power switch, you need to unplug it to power down.

    Should you unplug the high voltage plug or the low voltage plug? :)
  3. TVTV

    TVTV LI Guru Member

    The low voltage one, always, because when you power the equipment back up, if you insert the power source into the wall socket while having the low voltage end inserted into the equipment, a voltage surge may occur which can sometimes (granted, rarely) damage the equipment.
  4. asterger

    asterger Network Guru Member

    Most low voltage equipment design has DC voltage regulation. Therefore there is little chance of an over or under voltage condition. What I would be more concerned about is generating an electrostatic charge (spark) plugging in the low voltage power.

    Keep the low voltage plugged in to the router and unplug the AC power cord.


    -- asterger
  5. TVTV

    TVTV LI Guru Member

    I beg to differ. As most power supplies used for low-end routers only consist of a transformer, 4 diodes for regulating the voltage and maybe a cap to filter out the noise, they have no surge protection. ;)
    I'll grab my multimeter in the morrow and check my GL's power supply. I'll be back with details.
  6. The Doctor

    The Doctor LI Guru Member

    4 Diodes for regulating the voltage? Never seen that design before, but it sounds very similar to an unregulated power supply :biggrin:

    Most of the routers I've seen lately use a switching mode regulated power supply, as evidenced by the fact the supply feels like an empty box. I do recall have an older router which had a very heavy power supply, but it had a linear regulator inside the router.

    You are best to disconnect the AC side of the power supply to turn it off, you've got a bigger chance of power surge unplugging the DC connector.
  7. TVTV

    TVTV LI Guru Member

    Sorry, english is not my native language. Although i speak it fluently and have studied it for some 10 years, i've never had much use for technical terms, so i suck at that part.
    I meant to say that most small power supplies i've seen so far only use a diode (or a bridge) rectifier and a cap, i.e. they're plain (old school) (not switching) power supplies.
    If you're certain that the 54 series power supplies or the routers themselves have a built in regulators to prevent damage by voltage surges, i stand corrected.

    L.E. - Just checked the supply, as promised. It spits out 16.33 volts instead of 12. In contrast, my laptop's power supply's output is 19.44 volts, just 0.44 volts from the 19 it's rated for.
    The above test was done without load.

    I couldn't check for spikes as my digital multimeter is not fast enough to catch those. I'll look for my old analogue one and if i find it, i'll repeat the test.
  8. asterger

    asterger Network Guru Member

    See article and photograph at

    All models of the WRT54 have an internal (on router's main circuit board) regulation that clamp DC supplied from the external power cube.

    With internal regulation, it is always preferable to disconnect power from the AC main while leaving the low power DC plugged in.


    -- asterger
  9. TVTV

    TVTV LI Guru Member

    I see. Thanks for the explanation. So disconnect mains it is! :) Although i still think that the chance for a high-voltage electrostatic discharge between the router and the power chord is close to 0.
  10. Toastman

    Toastman Super Moderator Staff Member Member

    Just for people's interest, the normal WRT54GL power supplies sold in Asia contain the following:

    A transformer with internal thermal overload protection cutout.
    A bridge rectifier using 4 diodes
    A rather small reservoir capacitor (about 100uF as I recall).
  11. TVTV

    TVTV LI Guru Member

    Just as i suspected. ;)
  12. Planiwa

    Planiwa Network Guru Member

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