Earlier this week my pc died and I'm a bit lost in my diagnosis of the fault. Hopefully someone will read all this long post and can give me some advice.
The board is a MSI K8 Neo4 Platnium (MS-7125) and it has served me very well since I got it second hand. I do want to build a new pc but I'd like to do that gradually so I can research hardware more carefully so I'd like it if the K8 could serve me a bit longer.
As I'm a bit lost I'm wondering if bad caps could be the problem or if something else has gone bad. I've done lot's of googling and reading these forums without much luck on id'ing the cause.
What happened is I booted the pc and logged in and then left the room. Returning a few minutes later the pc was dead and would not turn on again. Nil nada zip nothing.
After some reseach I tested the power supply and made a discovery that many apparently have made. With the power supply not connected to the mobo in any way shorting the ps-on pin to ground turned the power supply on. When just the 24pin connecter is hooked up to the mobo the fans work but when the atx12 4 pin connecter is hooked up then nothing.
I specifically measured the ps-on pin when the atx12 4 pin was hooked up to the mobo.
- When the wall power is first turned on the ps-on pin is at 5v like it should be. When shorting the ps_on pin to ground (fpc button or just shorting the pins on the mobo) the ps_on pin goes initally towards zero but then goes to 14v! I've never seen reports with that in them.
The power supply is a Usicase, which I suspect is just another low end PS branded for a system builder. I opened it up and there was one slightly bulging cap which I replaced. Still got the same result. I also tried with another PS on hand, also not good quality (Shaw) with the same results.
So that brings me to the mobo. I've inspected it very carefully and can not see anything obviously wrong, no bulging caps or blackened mosfets, no scorch marks anwhere. There is one smd ceramic cap (I believe, one of those smd brown with silver ends things) right next to the 4 pin connector which has a bit of the brown chipped off but I think it has been like that for ever.
On the board near the CPU is 5 Rubycon 6.3v 3300uf caps, 4 brown (marked KZG) 16v 1500uf caps and a black w/ gold writing 6.3v 1800uf cap that has a M inside a square on it. Around the board in various spots are various small caps (green marked KZE, brown marked KMG and some black with the M logo). Again, none of the caps show any sign of bulging or pushing the bung out. I do know that this isn't the only failure mode.
So the big question before I try recapping it is could failed caps cause the problem I'm having (like causing the ps_on pin to go to 14v when shorting it to ground) or should I be looking for something else which I'm not sure I'll have the skill to tackle.
Thanks,
- Tim
The board is a MSI K8 Neo4 Platnium (MS-7125) and it has served me very well since I got it second hand. I do want to build a new pc but I'd like to do that gradually so I can research hardware more carefully so I'd like it if the K8 could serve me a bit longer.
As I'm a bit lost I'm wondering if bad caps could be the problem or if something else has gone bad. I've done lot's of googling and reading these forums without much luck on id'ing the cause.
What happened is I booted the pc and logged in and then left the room. Returning a few minutes later the pc was dead and would not turn on again. Nil nada zip nothing.
After some reseach I tested the power supply and made a discovery that many apparently have made. With the power supply not connected to the mobo in any way shorting the ps-on pin to ground turned the power supply on. When just the 24pin connecter is hooked up to the mobo the fans work but when the atx12 4 pin connecter is hooked up then nothing.
I specifically measured the ps-on pin when the atx12 4 pin was hooked up to the mobo.
- When the wall power is first turned on the ps-on pin is at 5v like it should be. When shorting the ps_on pin to ground (fpc button or just shorting the pins on the mobo) the ps_on pin goes initally towards zero but then goes to 14v! I've never seen reports with that in them.
The power supply is a Usicase, which I suspect is just another low end PS branded for a system builder. I opened it up and there was one slightly bulging cap which I replaced. Still got the same result. I also tried with another PS on hand, also not good quality (Shaw) with the same results.
So that brings me to the mobo. I've inspected it very carefully and can not see anything obviously wrong, no bulging caps or blackened mosfets, no scorch marks anwhere. There is one smd ceramic cap (I believe, one of those smd brown with silver ends things) right next to the 4 pin connector which has a bit of the brown chipped off but I think it has been like that for ever.
On the board near the CPU is 5 Rubycon 6.3v 3300uf caps, 4 brown (marked KZG) 16v 1500uf caps and a black w/ gold writing 6.3v 1800uf cap that has a M inside a square on it. Around the board in various spots are various small caps (green marked KZE, brown marked KMG and some black with the M logo). Again, none of the caps show any sign of bulging or pushing the bung out. I do know that this isn't the only failure mode.
So the big question before I try recapping it is could failed caps cause the problem I'm having (like causing the ps_on pin to go to 14v when shorting it to ground) or should I be looking for something else which I'm not sure I'll have the skill to tackle.
Thanks,
- Tim
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