Seasonic SS-660XP2 660W Platinum Supply Works But Fails Under Normal Load - Repairable?


Jan 24, 2023
Bought this Seasonic SS-660XP2 in 2014 and of course it is failing just out of warranty. Under normal load (generally under 100W) it works fine and will run "forever." If I run a graphics card heavy (300-400W total load), within a few hours (sometimes within 30 minutes or so, sometimes after a few hours), the PS just dies. If I toggle the power switch on the unit I am able to turn the PC back on.

I realize this is almost a throw away item, but might this be repairable? On one hand, it mostly works, but on the other hand, the problem doesn't show itself until a certain point. Not sure if this is thermal or not, but the fan does appear to still be operational. Hate to throw it away if it's possible to fix fairly easily. I'm an EE but not a technician and not power supply/CCA specialist but I have access to technicians who can do the work. Sometimes it can be as simple as replacing capacitors. I haven't opened it up yet.


[H]F Junkie
Jul 11, 2001
If I run a graphics card heavy (300-400W total load), within a few hours (sometimes within 30 minutes or so, sometimes after a few hours), the PS just dies

What are the other components in the system? A 660w PSU is not particularly powerful by modern standards. If your videocard is potentially using more than half of the available power, that doesn't necessarily leave a lot of extra for the rest of your system, especially if you have a power-hungry CPU. Fans, pumps (if water-cooling), hard drives, etc, all use power also.

The fact that it only fails over-time does seem to suggest that there might be a thermal issue at play. What sort of airflow do you have in your case? Ideal would be to have positive pressure inside your case, basically working in tandem with your PSU fan as air is pushed into your PSU (via the positive case pressure) and then expelled by the fan. On the other-hand, some cases have "odd" designs that essentially create a negative-pressure zone around the PSU (or overall negative pressure in your case), where the PSU fan would end up actually fighting against the airflow of your case. It could be something more simple - when was the last time you blew the dust out of the PSU?

It never hurts to check for leaky caps or other obvious signs of failure, but overall, power supplies don't simply fail due to age. A PSU from 2014 isn't even that old; I have several PSUs from 2007-2009 still in operation and they are doing fine. I have several old Macintosh computers from the 1980's and 90's that still work with their original power supplies. Electronics can easily last 50+ years unless there was a flaw in the design (bad capacitors, etc).


Apr 13, 2008
Repairable sure, if you had the full schematic and proper test equipment to troubleshoot it.