Power down and master/slave socket

  • Thread starter Thread starter Karsten Priegnitz
  • Start date Start date
K

Karsten Priegnitz

Hi,

I've got a master/slave socket (the ones that switch all the devices off
when the master device is turned off) to which I connected my PC as master
and my monitor and speakers as slaves. When I shut down the PC this doesn't
work until I turn off the ATX power supply unit with its little switch on
the back of the PC. Then the slave devices turn off and they even stay
turned off when I turn on the ATX unit again. When I boot up the PC the
slaves turn on again.

I have an Asus P4B-533M motherboard. Is there a possibility to make it turn
off completely when shutting down the PC?

thx
 
No.

An ATX power supply provides standby power to the motherboard at all times
after shutdown.
This is so the motherboard can detect when you press the power button on the
front of the PC, or the modem ringing or a LAN wake up signal and then turn
itself on.
This can only be stopped as you have noticed by turning off the master
switch on the power supply, if it has one (some do not).

John S.
 
Karsten said:
Hi,

I've got a master/slave socket (the ones that switch all the devices off
when the master device is turned off) to which I connected my PC as master
and my monitor and speakers as slaves. When I shut down the PC this doesn't
work until I turn off the ATX power supply unit with its little switch on
the back of the PC. Then the slave devices turn off and they even stay
turned off when I turn on the ATX unit again. When I boot up the PC the
slaves turn on again.

I have an Asus P4B-533M motherboard. Is there a possibility to make it turn
off completely when shutting down the PC?

thx
Click to expand...

That is because the power supply is still running and producing +5VSB,
after Windows shuts down. This means the power supply is still consuming
a few watts. If the master/slave device had a sensitivity setting,
maybe making it less sensitive would work.

What I like to do with today's power leaking devices, is put them
all on a power strip (six outlets plus switch). Then, at the end of
a session, I just flip the switch on the strip and all the "wall warts"
and standby power sources are all switched off. Even my LCD monitor
continues to draw current after it is shut off, so a power strip is
a cheap solution to the problem.

Depending on how your external speakers are designed, you might get
a big "whomp" from the speakers when they are switched off at the
wall. My cheap speakers shut down more quietly if switched off by
the switch on the front of them.

HTH,
Paul
 
Muttley said:
No.

An ATX power supply provides standby power to the motherboard at all times
after shutdown.
This is so the motherboard can detect when you press the power button on
the front of the PC, or the modem ringing or a LAN wake up signal and then
turn itself on.
This can only be stopped as you have noticed by turning off the master
switch on the power supply, if it has one (some do not).
Click to expand...

A friend of mine has bought a new PC and uses the same master/slave socket
bar as I do. It works with his mainboard. And as I wrote: when I turn of
the master switch on the ATX power supply and turn it back on the bar stays
"switched off". It seems to be possible to turn an modern PC on without
having power on the mainboard...

strange strange strange ...
 
You can adust a setting in the BIOS to make the PC bootup as soon as AC
power is applied to the unit.
"AC Power Loss Restart" in Power Options.

The power bar will have a detection threshold that determines how much
current flow is required to turn the slave sockets on, and another threshold
that determines how low the current flow must be to turn the slave sockets
off.

In your case, the power supply is drawing too much power after shutdown
(above the turn-off threshold) to allow the slaves to turn off.
The slaves only turn off after you turn off the main switch on the power
supply, which reduces the current flow to zero.
Also, when you initially turn on the main switch at the power supply, it is
not drawing enough power (below the turn-on threshold) to trigger turn-on of
the slave sockets. The current only goes above the threshold when you press
the power button to boot the PC.

Either his power bar has a higher threshold for slave turn-off or his PC
draws less power in standby than yours and therefore allows the slaves to
turn off at shutdown. Perhaps your power bar could be faulty too.

John S.
 
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