MSI 6337 815ET ver. 5 Doesn't Power Up

[smata67]

This motherboard would reboot every so often, then eventually completely failed. Failed as in the system will no longer even power up (PSU does not turn on). I disassembled the PSU and found some leaking Jamicons (3300uf/10V w/ ESR at .5, spec is .01) in there as well as a pair of blown load resistors. I obtained a new PSU, hooked it up and it too will not turn on. So now it is possible that the board is bad due to damage from the PSU OR that the board was bad anyway with the cap problem. If the PSU has somehow damaged the board, what components should I be looking at? I plan on taking ESR readings of the suspect capacitors (they are TEAPO on this board) to see if they were bad, but I am curious if this is really the problem because "not being able to power the system" is not listed as a symptom of the cap issue.

[Chris1992]

Re: MSI 6337 815ET ver. 5 Doesn't Power Up

Probably a combination of bad PSU and bad caps; a recap and good PSU would probably fix.

[Rainbow]

Re: MSI 6337 815ET ver. 5 Doesn't Power Up

I have MS-6337LE5 where the power button did not work, but the board worked fine when #PS_ON signal was grounded on the PSU manually. I traced the way from power button connector to 74xxx logic chip on the edge of board near last PCI slot. Resoldering the chip and some SMD components around fixed it.

[smata67]

Re: MSI 6337 815ET ver. 5 Doesn't Power Up

I have MS-6337LE5 where the power button did not work, but the board worked fine when #PS_ON signal was grounded on the PSU manually. I traced the way from power button connector to 74xxx logic chip on the edge of board near last PCI slot. Resoldering the chip and some SMD components around fixed it.

This would be an easy check. Did you just pull out the wire from the PSU going to Socket 14 and ground?

[Rainbow]

Re: MSI 6337 815ET ver. 5 Doesn't Power Up

I just put a small U-shaped wire (acutally a leg from a cap - a byproduct from recapping ) between the #PS_ON (pin 14, usually green) and nearest GND (pin 15). If this turns it on and it works, then there's something bad in the power on/off circuit. If it still does not turn on then there's a short somewhere.
Make sure the clear CMOS jumper is set to normal position.

[smata67]

Re: MSI 6337 815ET ver. 5 Doesn't Power Up

I took the board out and read the ESR for all caps with my Dick Smith meter. The Chiyyus or whatever the smaller 1,000uf are, all appear to be okay, read .02-.05. BUT, the 7 larger TEAPO caps in the VRM area all measured "0", which I think means they are all shorted, I am going to remove some and verify. The other few TEAPOs on the board read okay at .02 or so. No burned through transistor as others have reported and I found the 7xxxx chip near the PCI slot, but I don't see how in the world I'll be able to resolder these with my mediocre skills.

[Rainbow]

Re: MSI 6337 815ET ver. 5 Doesn't Power Up

Zero reading might be fine - as they're low ESR and they are connected in parallel so the effective ESR is even lower.

[smata67]

Re: MSI 6337 815ET ver. 5 Doesn't Power Up

Caps in parallel would add up and since there are 6 or so, .02x6=.12 would be an expected reading, but I am going to pull out, test out of cirucit, and see if they charge up. I did get continuity at the power switch jack on the board, but forgot to see if pin 15 and 14 indicate a short or not.

[Rainbow]

Re: MSI 6337 815ET ver. 5 Doesn't Power Up

ESR is resistance - so it decreases when there are more connected in parallel - just like with resistors. And that's also why they put more caps in parallel.