ES725 no longer boots PC after PSU replacement

[Anonymous user]

I've used an ES725 to protect my server for a couple of years. It's a dual core 2-drive system that doesn't do much, so rarely draws much power, and I was getting 25+ mins backup on my ES725.

After a lightning storm the building breakers blew, and the server never recovered (the PSU had died). I replaced the PSU (a no-name 500W unit) with an Antec 650 Watt green series unit, added 4GB (total of 6) and a 1TB drive in addition to the two 160GB units already in it.

Now, when plugged in to the battery protected ports, the PC won't boot. The UPS buzzes and clicks and the computer fans spin up for about a second and a half, and then it stops, shuts off, and tries again. It repeats until I turn it off. The system boots fine on the non-battery ports.

I cannot determine if the new equipment is overloading the UPS and shutting it down, or if the UPS is fried after the storm.

The server is very remote to me - it's an 8 hour flight to return to it when it dies (It and I live in different countries and there's no on-the-ground support staff). Currently I'm in the same country, coincidentally 1 week after it died, but I'm away from it for 4 weeks on other business, and so I'm asking the question without being able to yank the new HDD and/or RAM to see if that helps.



Any advice? 😃

Message was edited by: NFGpower

[Anonymous user]

The server's in Japan where, it must be said, I don't have a lot of luck with power as a rule. Cheap power supplies blow very often, so I'm not surprised to see this one has died. That's why, years later than I should have, I'm learning to use quality gear. Hence APC. 😃

Yes, the APC unit allows other things to boot on the battery terminals: the secondary redundant server, a Dell server unit with a P4 and single drive, boots without problem. Normally though I don't have this system battery backed at all, since it's rarely on active duty, so it does me no good to have it backed up now...

One other thing: the ES725 makes a faint but distinct whining sound while sitting idle, like a very quiet camera flash might do after it's charged. It's a slow pulsing sound, perhaps a 2-second cycle, as if it's just topping up the battery? I don't remember it doing this before, but I installed it a couple of years ago, so maybe it did and I never noticed. Not sure if that's a useful clue or not.

[Anonymous user]

Well, there may be some kind of issue with the new power supply and the UPS.

There is a few known issues with active PFC PSUs and UPSs that puts out what they call a stepped sinewave. Some of these PSUs tend to draw an amount of current that overloads the UPS when it is starting. One of the solutions given by APC is to pick an UPS that can deliver the amount of power the PSU can draw from the outlet when it first starts. In your case your PSU can draw as much as 650W + 20% since it is a 80% efficient PSU. Starting from this point it means you should pick at least a 1300VA UPS to handle the amount of current the new PSU can draw when it starts. A 1300VA UPS is capable of delivering 780W...

When your PSU tries to start, it can cause an undervoltage at the UPS transformer and it responds to this by transfering to the battery power which in turn can't handle the inrush current as well, and then it keeps clicking on and off the battery not allowing your PSU to start properly.

I'm not saying this is the problem you're having, I'm just saying there's a good chance your new PSU is causing this.

And about the whining sound that cycles on and off in a couple of seconds or so, both of my UPSes make this sound. I can only hear it when I turn my PCs off.

[Anonymous user]

Yeah, that's more or less where I was leaning. I was trying to find a bigger APC unit, but am not really finding much larger than the SUA750JB, a 500W / 750VA unit. If it's a simple overload situation, I didn't think a mere 50W / 25VA increase would sort anything out. If it was a dead APC unit, then this would be a suitable replacement.

Figuring out which problem I'm facing is the critical issue, but I've got ~3 weeks to nut it out before I need to make the purchase.

[Anonymous user]

I was able to resolve the problem by replacing the 650W PSU with a smaller one.

I learned several things:

1. The PSU draws its full allotment of power on startup, no matter if the PC needs it or not. I believed the power draw would only be what the PC needed, but the PSU inrush on startup overwhelmed the UPS.

2. I thought the UPS would only shut down if the Watts drawn were more than the UPS allowed while in battery mode. But it turns out it'll shut down if it's on mains power as well.

Thanks to Arai-san in the Japanese office for helping me via email.

[Anonymous user · Accepted solution]

I've used an ES725 to protect my server for a couple of years. It's a dual core 2-drive system that doesn't do much, so rarely draws much power, and I was getting 25+ mins backup on my ES725.

After a lightning storm the building breakers blew, and the server never recovered (the PSU had died). I replaced the PSU (a no-name 500W unit) with an Antec 650 Watt green series unit, added 4GB (total of 6) and a 1TB drive in addition to the two 160GB units already in it.

Now, when plugged in to the battery protected ports, the PC won't boot. The UPS buzzes and clicks and the computer fans spin up for about a second and a half, and then it stops, shuts off, and tries again. It repeats until I turn it off. The system boots fine on the non-battery ports.

I cannot determine if the new equipment is overloading the UPS and shutting it down, or if the UPS is fried after the storm.

The server is very remote to me - it's an 8 hour flight to return to it when it dies (It and I live in different countries and there's no on-the-ground support staff). Currently I'm in the same country, coincidentally 1 week after it died, but I'm away from it for 4 weeks on other business, and so I'm asking the question without being able to yank the new HDD and/or RAM to see if that helps.



Any advice? 😃

Message was edited by: NFGpower