Two motherboards, need help to fix them.

[Dan81]

Re: Two motherboards, need help to fix them.

Are these ohm readings taken from the switches alone or from the motherboard pin headers? Normally OPEN switches should read as zero ohms when closed (pushed in) and infinite when open (not pushed in).

MB pin headers, since I am breadboarding the board.

[Sparkey55]

Re: Two motherboards, need help to fix them.

MB pin headers, since I am breadboarding the board.

have you tried disconnecting the RESET switch from the motherboard and use it in place of the PWR switch?

[stj]

Re: Two motherboards, need help to fix them.

i test boards by just shoving my screwdriver between the pins - ghetto!

[Sparkey55]

Re: Two motherboards, need help to fix them.

i test boards by just shoving my screwdriver between the pins - ghetto!

I would normally suggest that approach but I am trying to determine it the problem is with the motherboard or externally. Hence trying to rule out the switches as a problem since those items are common failure points.

[Dan81]

Re: Two motherboards, need help to fix them.

have you tried disconnecting the RESET switch from the motherboard and use it in place of the PWR switch?

Erm...

The measurements were done on the pin headers. So using the reset switch in place of PWR would do the same.

stj - Had it been that easy, the problem would be fixed by now

[Sparkey55]

Re: Two motherboards, need help to fix them.

Erm...

The measurements were done on the pin headers. So using the reset switch in place of PWR would do the same.

stj - Had it been that easy, the problem would be fixed by now

Switches can and do go bad from time to time. Since you did not say that you tested the switches that is the most logical test to perform in order to rule out external connector issues. Using the RESET switch for a PWR switch will rule out a bad switch for PWR ON and OFF and just the opposite if the RESET switch was bad. Since you are not doing a follow up on our suggestions we have no way to know if those suggestions are working or not. That makes it difficult to troubleshoot the problem. What exactly did you short on the motherboard? The more information that you give the better we can help you.

[Sparkey55]

Re: Two motherboards, need help to fix them.

Have you checked the BIOS setting for the PWR ON switch behavior? Chose the option for instant power off or holding the switch in for greater than 4 seconds? Your symptoms suggest a problem with the Southbridge chip. A corrupt BIOS is also possible.

[Dan81]

Re: Two motherboards, need help to fix them.

Have you checked the BIOS setting for the PWR ON switch behavior? Chose the option for instant power off or holding the switch in for greater than 4 seconds? Your symptoms suggest a problem with the Southbridge chip. A corrupt BIOS is also possible.

There's none for any switch, and I just checked all settings in the BIOS again this morning.

SB isn't bad or else it would get burning hot to the touch.

BIOS was updated today, and I get the same behaviour.

I am not using any switches on the main panel, hence why I didn't bother with measuring them, as I never used this board in a case.

As for what I am shorting, it's the two power switch pins (pins 7 and 8 marked in black) on the JFP1 header (JFP2 is for the case speaker and power LED).

[Sparkey55]

Re: Two motherboards, need help to fix them.

There's none for any switch, and I just checked all settings in the BIOS again this morning.

SB isn't bad or else it would get burning hot to the touch.

BIOS was updated today, and I get the same behaviour.

I am not using any switches on the main panel, hence why I didn't bother with measuring them, as I never used this board in a case.

As for what I am shorting, it's the two power switch pins (pins 7 and 8 marked in black) on the JFP1 header (JFP2 is for the case speaker and power LED).

Power Management Setup>Power Button Function

Southbridge and/or the associated parts can be bad without getting hot.

According to the manual The power switch should be connected to pins 6 and 8 not pins 7 and 8.

The reset switch should connect to pins 5 and 7.

[Dan81]

Re: Two motherboards, need help to fix them.

Power Management Setup>Power Button Function

Southbridge and/or the associated parts can be bad without getting hot.

According to the manual The power switch should be connected to pins 6 and 8 not pins 7 and 8.

The reset switch should connect to pins 5 and 7.

I accidentally shorted the 5v rail to the green wire once (it didn't respond to the power switch once and I figured out shorting the green to black on the ATX header would fix that - bad idea. No, it wasn't the 5vSB rail that was bad back then as all PSUs I have are recapped) and since then this happens. It's not 5vSB (I think that's what the SB runs from? Saying this because most burnt SB are caused by bad 5vSB) that is the culprit, so the Southbridge is STILL alive. Also, MB was seldom used by its original owner, because he complaint it was finnicky with RAM. (more like his RAM sticks were cheap crap, as both a A-DATA stick and a Corsair XMS POST'd successfully)


Power Button function is set to Power Off, and I figured out I mismatched the pins in my previous post - it's 6 and 8, as you said. Nevertheless I still have the problem (and yes, I am shorting the right pins ever since the beginning of this thread, even if I mismatched the numbering of the pins in my post.

This is a hardware problem unrelated to the physical power switches OR the BIOS or the southbridge. I think I should make a video for you all to see what is the exact problem.

As for the second board, it's already trashed - that one actually HAS a bad SB, even if it turned on for 3 seconds. (and the 5v rail on it might be shorted as I measured about 28ohms on it, way too much than on 12 and 3.3v)

[stj]

Re: Two motherboards, need help to fix them.

trace the switch line of the atx socket back to it's source incase there is a shorted transistor or fet on it.