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just brew it!
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Re: Computer starts for 3-5 seconds, resets, stays on but does nothing.

Sun Aug 13, 2017 10:11 am

HERETIC wrote:
just brew it! wrote:

Back in the day, it was also possible to get the power connector onto the floppy drive offset by 1 pin. Most drives were keyed to prevent this, but the connector was flexible enough that you could still push it on. I melted the insulation off the floppy power leads of a PSU once, by doing this.

Don't have to go back that far in time either-most PCI-SATA add in cards used floppy power connector.
My son did exactly the same thing.........
Was surprised PSU-SC didn't activate................

Ahh, now that you mention, IIRC I've seen USB add-in cards with that arrangement. I don't recall seeing it on SATA cards though.

At lower voltages a short can be hard to distinguish from a heavy load, especially with thinner gauge wire. Wire can have enough resistance that the PSU doesn't see it as a dead short. Or the PSU's protection simply sucked.

Kougar wrote:
just brew it! wrote:
Fortunately I didn't destroy anything the time I did this. Symptoms were very similar to the OP. :wink:

My understanding was it became such a problem that mainboard makers began adding voltage sense protection to EPS12V connectors as to either not power on or initialize the board when that happened.

Could be. I imagine they could probe the EPS12V rail using a circuit powered off of the 5VSB rail, to decide if it is grounded out before telling the PSU to switch on the other rails.
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Re: Computer starts for 3-5 seconds, resets, stays on but does nothing.

Sun Aug 13, 2017 2:17 pm

I sent in the board with my cpu and ram, so I'll be sure to get back a working unit. No more guess work =)

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