Jumper cap on PWR_SW with no BIOS?

[OVER10RD]

so i have an old mobo that i use for testing fans and stuff. it has a corrupted bios that cannot be fixed by clearing CMOS.

since it's a hassle to power up the board using a screwdriver, i'm wondering if i could just bind the power switch pins on the front-panel header with a jumper cap.

would it work?

would it auto shut down?

or would it damage the mobo or components attached to it since there's no bios?

[Rugg]

Power button is just an ordinary electrical switch, so if you can get the connectors onto the mobo pins, should work just fine.

[Kilrah]

A jumper cap will do the exact same thing as a screwdriver - obviously you need to place it and remove, can't leave it on. 

[Moonzy]

u can use it to short, but u cant leave it on because that would equal to holding the power button, which in most cases shuts the PC back off again

[mariushm]

You need a temporary (momentary) button.  Click once to start, hold for 4+ seconds to shut down. 

 

[OVER10RD]

20 minutes ago, Kilrah said:

A jumper cap will do the exact same thing as a screwdriver - obviously you need to place it and remove, can't leave it on. 

14 minutes ago, Moonzy said:

u can use it to short, but u cant leave it on because that would equal to holding the power button, which in most cases shuts the PC back off again

 

8 minutes ago, mariushm said:

You need a temporary (momentary) button.  Click once to start, hold for 4+ seconds to shut down. 

 

but would it shut down by holding the power button without a bios?

if it doesn't, will it damage any pc parts plugged into the mobo?

[Moonzy]

1 minute ago, OVER10RD said:

 

but would it shut down by holding the power button without a bios?

if it doesn't, will it damage any pc parts plugged into the mobo?

good question, i dont know how a PC acts without a functioning bios since i never had that happen to me

 

i dont think bios controls voltage of other components other than CPU and RAM, so... there's that?

 

all in all, im not too sure, sorry

[mariushm]

6 minutes ago, OVER10RD said:

 

but would it shut down by holding the power button without a bios?

if it doesn't, will it damage any pc parts plugged into the mobo?

I think it's undefined behavior, up to the chipset... I would guess it keeps the system in a reset loop, like holding down the reset button... but I'm not sure. 

 

Either way, seems like super waste of space to have a whole motherboard just for the fan headers ... why don't you go and desolder the headers and solder some wires on them separately to connect to your power supply?  or buy molex / sata to fan header adapter cables.

 

Or fix the motherboard, by replacing the bios chip with another one with the proper bios written in it. 

 

[Kilrah]

33 minutes ago, OVER10RD said:

but would it shut down by holding the power button without a bios?

You can't be "without a BIOS", a PC will not boot without a working BIOS. 

[OVER10RD]

1 hour ago, Moonzy said:

good question, i dont know how a PC acts without a functioning bios since i never had that happen to me

 

i dont think bios controls voltage of other components other than CPU and RAM, so... there's that?

 

all in all, im not too sure, sorry

yeah i can try placing the jumper cap on and find out for certain.

it's just that i was was worried doing it would fry the components. as long as it has no risk of damaging the psu, i'll test it

[Moonzy]

1 minute ago, OVER10RD said:

as long as it has no risk of damaging the psu

I would think the chances are pretty slim, but I can't say that it won't happen for sure

[OVER10RD]

2 hours ago, mariushm said:

I think it's undefined behavior, up to the chipset... I would guess it keeps the system in a reset loop, like holding down the reset button... but I'm not sure. 

 

Either way, seems like super waste of space to have a whole motherboard just for the fan headers ... why don't you go and desolder the headers and solder some wires on them separately to connect to your power supply?  or buy molex / sata to fan header adapter cables.

 

Or fix the motherboard, by replacing the bios chip with another one with the proper bios written in it. 

 

this mobo just works without posting. doesn't go into a boot loop.

and it's an old mobo lol (from my first build, in fact) so there's no use of swapping the bios chip.

fan header adapters are a nice idea though