Motherboards boots up and holds for 20 secs, then shutdown

[Snayperskaya]

So, I've grabbed this board (a Tyan S7012) again after letting it rest for some time. Tested it with a E5506 (80W TDP, prolly draws way less than this), booted into Windows, everything working.

Swapped the CPU for a X5690 (130W TDP) and BLAM! 20 seconds after booting, it abrputly shutdowns. It happened before (thus the first sentence). I'm hearing a very quiet "shh" sound from the caps - this board uses polymers (I think they are NCC since it have something that resembles their logo) and electrolytics (SUNCON and NCC KZG series). None of them have bulged/leaked.

Never did a recap on a server-grade motherboard before (PCB back is heavy with SMD components), so... Where should I start (and I'm actually assuming it is a cap problem because of the sound they (?) make, but I'm not sure)?

[Sparkey55]

Re: Motherboards boots up and holds for 20 secs, then shutdown

So, I've grabbed this board (a Tyan S7012) again after letting it rest for some time. Tested it with a E5506 (80W TDP, prolly draws way less than this), booted into Windows, everything working.

Swapped the CPU for a X5690 (130W TDP) and BLAM! 20 seconds after booting, it abrputly shutdowns. It happened before (thus the first sentence). I'm hearing a very quiet "shh" sound from the caps - this board uses polymers (I think they are NCC since it have something that resembles their logo) and electrolytics (SUNCON and NCC KZG series). None of them have bulged/leaked.

Never did a recap on a server-grade motherboard before (PCB back is heavy with SMD components), so... Where should I start (and I'm actually assuming it is a cap problem because of the sound they (?) make, but I'm not sure)?

The "shh" sound that you are hearing is probably the KZG caps venting built up hydrogen gas and electrolyte vapor. I have seen this happen with KZG and KZJ caps venting through the rubber bungs instead of venting at the top of the cans.

[Snayperskaya]

Re: Motherboards boots up and holds for 20 secs, then shutdown

Nice, I didn't know that they could act like this.

Given this symptom, should I go for a recap? I'm pretty green with mobo reparing.

Is swapping the electrolytics with polymers for extended life doable?

[Snayperskaya]

Re: Motherboards boots up and holds for 20 secs, then shutdown

I'd love to hear from anyone with expertise in mobo repair about this one.

[sam_sam_sam]

Re: Motherboards boots up and holds for 20 secs, then shutdown

If you have a vacuum pump type Desoldiering Gun it can be done
If you have a temperature controlled hot air gun
If you take your time and do not get in a hurry

Heat the pad and pin on the cap with the Desoldiering gun until the cap pin is lose then suck the solder a way when I do this I might have the temperature set a 800* F but I only leave the heat on long enough to get the pin lose then remove the heat

If the solder close pin hole and it has ground plane then it can become tricky to get the solder off the pin hole then you want to have a temperature controlled hot air gun and your Desoldiering gun at the same time one on each side of the board