Cold start problem with PS?

[chrisgar]

I am planning on upgrading on old Athlon 64 3700+ system but this system has an odd problem. When the power to the MB is cut (eg unplug or turn off PS from the back) I can no longer start it with the case switch. The only way I found to make it work after an unplug is to open the case and jump the ATX green Power On wire to ground. That causes the fans to spin up, etc. After that the case switch works to warm start and I'm fine till the next unplug or power outage.

Is this a MB problem or a power supply problem? I'm considering keeping my Antec Smart Power 500W supply for the upgraded system but not if it is the source of the cold start issue.

The upgrade will be the following fairly standard build. The 500W PS should be plenty for these efficient parts. I like to run my system cold and quiet with a big cooler and fan controllers turned low.

Intel Core i5 750 (overclock only while it stays quiet)
GIGABYTE GA-P55M-UD4
XFX HD-577A-ZNFC Radeon HD 5770 (I want the external venting in this model)
COOLER MASTER Hyper 212
G.SKILL 4GB (2 x 2GB) 240-Pin DDR3 SDRAM DDR3 1333
24 inch LCD - TBD

Any ideas about the cold start problem? Any recommendations for this build?

thanks

 

[jsc]

Sounds like a PSU problem. Only way to tell for sure is by substituting a known good one from a similar system.