Seasonic X750 issue

[ilya]

Hi there, I recently bought the Seasonic X750 and I've been having issues getting it to start while warm.

I was just doing a bit of light surfing and then my uncle's shipment of DDR2 arrived and I needed to test if all the sticks were working real quick. So I turned off my computer, flipped the PSU switch off and swapped components. Then the PSU wouldn't start up properly, Power LEDs turned on and stayed on, fans spun up and stopped, then the system didn't even try to POST. At first I thought my PSU was dead or something, but after letting the unit cool off for about 30 minutes, it was working fine again. However, every time I turn off my computer and turn it back on again, I get the same problem. The PSU is barely warm and it won't start up unless its at room temperature.

I contacted Seasonic support and they just told me it's normal for the fan to not spin, however I mentioned in my email that I COULD get the fan spinning. I've sent a reply to clarify that and I've been waiting a few days for a reply.

Having to wait for the PSU to cool off all the time is incredibly inconvenient for me as I do a lot of component swapping and testing for friends and family.

This is a new unit and has been like this since I got it, does anybody know anything about this unit or similar PSU issues? I don't want to RMA this unit until I'm sure I need to so any input would be helpful, thanks.

[gingerbee]

there's more wrong with it then what you think. the fans only spin up on all the seasonic's i have owned when there's more then 250 watt load on it any less then that they don't spin but with an over heating unit i would be looking for an rma. jmo good luck

[Zero82z]

Can you try the PSU in a different system? I have a feeling this might just be a compatibility problem between it and your motherboard. If it still doesn't work, then the PSU is most likely faulty.

[ilya]

Originally Posted by gingerbee

there's more wrong with it then what you think. the fans only spin up on all the seasonic's i have owned when there's more then 250 watt load on it any less then that they don't spin but with an over heating unit i would be looking for an rma. jmo good luck

I'm having the same thoughts but I really don't wanna have to RMA and a naive little part of me refuses to believe such a high end product can be defective.

Originally Posted by Zero82z

Can you try the PSU in a different system? I have a feeling this might just be a compatibility problem between it and your motherboard. If it still doesn't work, then the PSU is most likely faulty.

I think I'll try this first although I doubt the compatibility is the issue.

Thanks for the opinions I'll post again if I figure this out.

[ilya]

So after some horrific technical support from Seasonic and countless hours of tinkering, I think I resolved the problem. The PSU was originally top mounted and caught a lot of ambient heat. The unit doesn't turn on the fans unless there's enough power draw AND enough heat, and the anti-overheat circuit breaker thing is a separate device. So what happened was the unit thought it was overheating even though it wasn't that warm at all. (not sure that even makes sense) So what I did was I turned my Zalman 9500 90degrees clockwise and Voila! No more problems. I was actually surprised that hot air from the CPU HSF was enough to cool off the unit, but I didn't feel too good about blowing hot air into the PSU so I bought a new case with a bottom mount for the PSU, no problems whatsoever with the new case.

Seasonic technical support was really no help though, next time I a PSU, it might be a Seasonic, but it's going to be a Corsair branded one.

On a side note, after some voltage testing I found that my unit has voltage regulation that's tighter than its rating of +/-3%. :)

[gingerbee]

your a first. I have never heard of seasonic being a problem. adn yes there units are built to very high standers ( or just buy the new antec true power, because there seasonic's )

[Zero82z]

Originally Posted by ilya

On a side note, after some voltage testing I found that my unit has voltage regulation that's tighter than its rating of +/-3%. :)

You would need to measure the regulation across the full load range to verify that, but it's not surprising or out of the ordinary to see 1-2% regulation or even better from a high-end Seasonic unit.