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Power issues

Really weird issue (sorry for the length). Have a Dell Server plugged into an APC smartups. A couple of weeks ago, it wouldn't turn on. I reseated the dual hot-swappable P/S and one came on the other did not (red error light on front). Thought it to just be a bad P/S- ordered a replacement. Next morning, server is off again. Tried to reseat the P/S, did not work.  Contacted Dell "Eneterprize Chat". They suggested the Power Distribution Board. Ordered it. Installed it with two new P/S's. neither worked. Put original PDB back in and one P/S worked, one didn't. I even moved good P/S to top and bottom slot to test, worked in both slots.  Next morning, no power. moved p/s to top slot and it came back on (but not on bottom). contacted Dell Chat and they said, must be the motherboard. Bought new motherboard, put it in and tested with another power supply. worked for a day and then no deal. contacted chat and they suggested "Environmental Issues", so I have currently moved the plug from old APC to new.  Old APC did have an additional server running on (but it had been there for the past three years running together just fine).  I have no idea what to do.  i am waiting for my new P/S to come in before I let it go over night.  Currently I am logging in remotely to shut it down after backup is complete.  Anyone seen something like this before?
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dayvid4444

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I was under the impression that the original APC was fine.  My other server is not experiencing any power issues.  Could this just be isolated to the Dell?
Or you can try running it all night off of any UPS, with only one PS, just for the heck of it.
Only concern is that taking off a Power surge device could present worse danger than leaving it on the original P/S.  I have it on a newer APC but won't leave it up all night untill I have a replacement P/S so i won't be down the next day.
UPS units that do not put out a true sine wave are known to damage PSU's that have PFC.

PFC (especially Active PFC) only works properly with a true sine wave.
When PFC is fed a square, stepped sine, or sawtooth wave form the 'pulsing effect' causes the PFC to respond in a manner the produces voltages in the first stage of the PSU are far higher than the components are rated for.

This is a major problem if your AC source is 220v.
If you have 120v AC it depends on the specific PSU design.
- A full active PFC PSU that's designed for 120-220v may (may) have high enough rated components if on 120v, but not when on 220v.
- These would be the PSU's that take either 120v or 220v without using a switch on the back.

It's not a problem with older designs of PSU's that have no PFC at all.
[Which is what non-sine wave UPS units are designed for.]

It's a matter of power supply designs changing with the times and UPS units based on older and incompatible designs still being common and much less expensive that true sine wave UPS units.

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