Bypassing the power switch

[Sinus Logarithme]

To power up the computer, you must physically push the front power switch
(which, I think, is called a soft switch). The back power button, which is a
regular on/off switch, must be on - no problem there.

I need to have the computer power up by itself in case of a power shortage.
There is no setting in the Bios Setup that can be changed for that. The
subject was discussed here a few years ago, without result.

I thought of something. There are, I believe, 2 wires from the mobo to the
soft switch. I could short them, I mean cut them and solder them together.
1) Would that do the trick ?
2) Is there any other way ?

The setup:
Abit BH6 rev. 1.0
Pentium2 350 MHz
Chipset: Intel 440BX
Power switch: the "soft" type
Award Bios with the last update: SS
06/28/2000-i440BX-W83977-2A69KA1EC-SS
OS: irrelevant (Windows)

 

[ric]

To power up the computer, you must physically push the front power switch
(which, I think, is called a soft switch). The back power button, which is a
regular on/off switch, must be on - no problem there.

I need to have the computer power up by itself in case of a power shortage.
There is no setting in the Bios Setup that can be changed for that. The
subject was discussed here a few years ago, without result.

It's been discussed many times *this* year.

I thought of something. There are, I believe, 2 wires from the mobo to the
soft switch. I could short them, I mean cut them and solder them together.
1) Would that do the trick ?

No. It is a "momentary" switch, meaning it makes "momentary" contact,
then returns to its normal open position.

2) Is there any other way ?

Yes. Place a small cap across the switch. The cap will look like a short
upon application of power, then act like an open once it charges.

 

[Sinus Logarithme]

I am just a layman:
Please say how many microfarads or picofarads I should use.
Is the capacitor type important ?
And do you mean all I have to do is having it join the 2 wires I mentioned
before, without dismantling the switch ?

 

[ric]

[top posting corrected to improve readability]

I am just a layman:
Please say how many microfarads or picofarads I should use.

Depends on the MB. Try about a 1 uF to begin with.

Is the capacitor type important ?

Not terribly, but a non polarized cap will make your installation easier.
I'd stay away from tantalum. Try a regular ceramic disk.

And do you mean all I have to do is having it join the 2 wires I mentioned
before, without dismantling the switch ?

Yes, in parallel with the working switch. Your switch will still operate
normally. [I'm referring to the small front panel momentary switch.] I
normally install it where the switch plugs into the MB header.

 

[Sinus Logarithme]

Ric, thank you, thank you, thank you. It has been a problem for 7 years, and
now it's gone.
I used a .47 uF, the closest to 1uF that I had in my stuff. It's square and
unpolarized, probably ceramic.
I installed like you said, in parallel with the switch. The machine boots
when I switch the surge protector on.
After booting from a diskette, the computer switch is functional: I can
power down and then up. When Windows shuts down the computer, I can power it
up again with the reset button, but not with the soft switch. I wonder why.
It's just a matter of curiosity, I am perfectly happy now.

[top posting corrected to improve readability]

I am just a layman:
Please say how many microfarads or picofarads I should use.

Depends on the MB. Try about a 1 uF to begin with.

Is the capacitor type important ?

Not terribly, but a non polarized cap will make your installation easier.
I'd stay away from tantalum. Try a regular ceramic disk.

And do you mean all I have to do is having it join the 2 wires I mentioned
before, without dismantling the switch ?

Yes, in parallel with the working switch. Your switch will still operate
normally. [I'm referring to the small front panel momentary switch.] I
normally install it where the switch plugs into the MB header.

 

[ric]

Ric, thank you, thank you, thank you. It has been a problem for 7 years, and
now it's gone.

Por nada.

I used a .47 uF, the closest to 1uF that I had in my stuff. It's square and
unpolarized, probably ceramic.

Close enough. If it works for your MB, it works.

I installed like you said, in parallel with the switch. The machine boots
when I switch the surge protector on.
After booting from a diskette, the computer switch is functional: I can
power down and then up. When Windows shuts down the computer, I can power it
up again with the reset button, but not with the soft switch. I wonder why.
It's just a matter of curiosity, I am perfectly happy now.

Hmmm...odd. Try holding the switch in longer. Odd indeed...

You might want to experiment with smaller caps, such as 0.22 uF or
0.10 uF.

 

[Sinus Logarithme]

Hmmm...odd. Try holding the switch in longer. Odd indeed...
It doesn't work.

You might want to experiment with smaller caps, such as 0.22 uF or
0.10 uF.

If it's not broken, don't fix it... I prefer to concentrate on my software
problems now. Thank you again.

 

[David Maynard]

It doesn't work.



If it's not broken, don't fix it... I prefer to concentrate on my software
problems now. Thank you again.

It sounds like Windows is not actually turning it off.