Hi, i have a h81m-k motherboard. It wont turn on. And i realize the motherboard fan is running before power on. I check the +12V on fan socket (before power on), it has 5Vsb from psu and 12V cpu vrm also have 5Vsb and maybe that cause my motherboard immediately turn off after power on. Any idea how that can happen?
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Motherboard fan running before power on
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Re: Motherboard fan running before power on
Originally posted by stj View Post?
so your psu is putting 5v on the 12v rail in standby?
or your board is?Last edited by utzlol; 06-16-2020, 08:13 PM.
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Re: Motherboard fan running before power on
Originally posted by stj View Postso what do you see if you check between the 5v-standby and 12v pins with a meter set for resistance, and diode-mode?
try with leads both ways.
After atx plug
GND - 12V (88 ohm)
GND - 5V (86 ohm)
12V - 5V (173 ohm)
Before atx plug
GND - 12V (113 ohm)
GND - 5V (742 ohm)
12V - 5V (858 ohm)
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Re: Motherboard fan running before power on
Like, an ich fan? The h81m-k dosen't have one.Cap Datasheet Depot: http://www.paullinebarger.net/DS/
^If you have datasheets not listed PM me
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Re: Motherboard fan running before power on
Can we have some pictures of the setup and the PSU?
What brand and model is the power supply?
Does the PSU fan run when connected to the motherboard?
- If yes, then disconnect PSU from the motherboard and plug PSU into the wall. Does the PSU fan spin now? Does it has 5VSB showing 5V, but all other outputs zero (or close)?
Also, what's the history on the PC you are troubleshooting? Is it yours or someone else's? Do you know when or what (last use) caused the PC to malfunction?Last edited by momaka; 06-17-2020, 04:59 PM.
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