atx mobo not powering

...used flat screw to short the remote power switch but no effect. Not powering up still. by the way, I tried shorting the green wire and ground (black) while connected to the mobo. It powers up but it always says no "KEYBOARD ERROR OR KEYBOARD NOT PRESENT". Hi, Are the wires on the remote power switch green and black ?. From what u said i can't help concluding that the wires between switch and mobo's power switch connector have a break. Boot up stalls sometimes when no keyboard is connected. One has to enter bios (press delete to enter bios) and select the appropriate "halt" options ( All but keyboard ) Connect a keyboard and see what happens. Doesn't the screen prompt u to continue by pressing F7 ?

Did you check the battery?

Geoff.

Hello, yhan! You wrote on 13 Sep 2005 00:20:25 -0700:

y> greetings,

y> had anyone come to this problem: i have an atx mobo that does not power y> up. I tried the suspected atx psu to other motherboard but it works y> fine. So I connected it again to the mobo with problem, tested the y> switch, no problem, used flat screw to short the remote power switch y> but no effect. Not powering up still. The fact that its psu works in y> the other motherboard means that the atx psu is not the problem. I also y> tried another known working psu but it still does not power up. If the y> problem lies in the motherboard circuitry for remote switch, is there y> any possible alternative to power the computer? by the way, I tried y> shorting the green wire and ground (black) while connected to the mobo. y> It powers up but it always says no "KEYBOARD ERROR OR KEYBOARD NOT y> PRESENT". y> anyone please enlighten me of this problem. y> thanks in advance, y> ian

Remove the mainboard from the case, carefully examine all electrolytic capacitors for bulging tops or leaking electrolyte. NEVER enable PSU by jumping the green to ground while it's connected to the mainboard. If the mainboard doesn't want to start, it has a good reason. Try the mainboard on the desk with only the Monitor, PSU and Keyboard connected. If you still have no luck, and even if you see no problem with the caps, I would still suspect them anyway. From what you say the CPU and memory are OK, The PSU is OK that only leaves the Mainboard.

With best regards, 3T39. E-mail: snipped-for-privacy@hotmail.com

i tested the switch using ohm meter and there is working fine. I think it would be difficult to trace the line if the problem is the mobo.

yes i checked the battery. it's ok. maybe the fine wire in the mobo from psu connector to the remote mobo switch connector had gone open. possible cure?

Remove the mainboard from the case, carefully examine all electrolytic capacitors for bulging tops or leaking electrolyte. NEVER enable PSU by

jumping the green to ground while it's connected to the mainboard. If the mainboard doesn't want to start, it has a good reason. Try the mainboard on the desk with only the Monitor, PSU and Keyboard connected. If you still have no luck, and even if you see no problem with the caps, I would still suspect them anyway. From what you say the CPU and memory are OK, The PSU is OK that only leaves the Mainboard.

- thanks for the input. i inspected capacitor, nothing bulging out. i dont have an esr meter, only ohmeter but it would be difficult to test capacitor in- circuit... and i think desoldering a suspected caps in the mainboard would be a difficult tastk.

new progress..

remove the mainboard from the case. connected the memory and cpu, then connect to the monitor. turned on, yes it powered up but after the monitor got a display for a few seconds only, maybe 2 sec, it shuts down. repeat the test and achieve same result. what causes the computer to shutdown?bad/shorted motherboard?

thanks,

ian

It could be anything- incorrect PSU voltages, bad chipset, bad caps or, about the worst scenario- CPU regulators! Don't use a CPU you value while testing a motherboard- it could destroy the CPU very quickly indeed. My advice- bin the mobo and get a new one.

Dave

More to the point, it would be a complete waste of time. An ohmeter will tell you nothing worth knowing about the caps, other than whether they're shorted.

On some motherboards, it is a real challenge cleaning out the plated through-holes on the ground side to accept the new caps. Others aren't so bad.

Dave

check the caps that are around any hot spots on the mobo like around the reguators and cpu, i did a p2 the other day, it was caps near the mobo regs.

yhan ha scritto:

Maybe defective Electrolytic caps.

I.