Taking odds that a system will boot up w/o issues after a big boom

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Al Special Project $250 donor
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Message 1927361 - Posted: 30 Mar 2018, 19:30:49 UTC

Had a little excitement at the shop yesterday. I've moved a few of my bigger rigs to my shop over the last 2-3 weeks, trying to downsize a little here at the home front, and as PSU's tend to run a little more efficiently on 240v, I've put most of them on that as well, since I'd planned ahead a bit and had a number of 20a 240v outlets installed when I did the buildout.

So anywho, I think I have maybe 5-6 systems running on it right now, and was putting together an Asus X99 Deluxe system with two 1070 Hybrids on it, along with a Corsair AIO CPU cooler, all of which was going to be running on 240v like the other systems. I had a spare EVGA 1000 Gold PSU that I thought would be a good fit for this system, as it's eventually going to be overclocked aggressively and will probably pull a good 500w+ out of the wall, best guess at least. I remember back in the bad old days, that PSU's had a switch to go between 120 and 240, but most modern ones for a number of years now don't, though I always check to be sure if I am going to not be running them on 120v. I did check, it said 120-240v input, so all was good there.

The system was a pull out from my CAD case, both the PSU and MB, so I knew that they were fine when I hooked them up that everything last time (on 120v of course) was perfectly fine. I installed the 2 video cards and the Intel SSD, hooked up all the wiring to everything, and plugged the cord into the back of the PSU. So far so good.

I then turned on the switch, and Boom, sounded like a .22 went off inside the PSU, it let out a little puff of smoke, and I quickly yanked the cord out of the back of it, but by that time, whatever had happened, happened. I disconnected it from everything, and called EVGA. As I had registered it, they got the RMA started right away, so I just went into their site and pushed the advanced replacement forward by putting in my CC info so they could ship it out right away. If I'm lucky, it'll go out tonite, though I really don't need it immediately, I have a PCP&C 1200w that I am going to use in it's place.

Sooo.... I of course explained my concerns about the possibility of issues with all that expensive hardware that was attached to it when it blew, and he said that if there were any issues with the GPU's, they would have no issue sending out replacements, and I mentioned that I had concerns about the MB and all the components that were installed on it as well. He of course thought they would be fine, the PSU sacrificed itself, etc, and I said that I hope so, but had him document what I have on it, in case it took something(s?) out. I haven't had a chance to install the other PSU yet, so I'm wondering what you guys think about my chances things are FUBAR when I get it hooked up?

This is the 2nd time this has happened to me with an EVGA PSU, though the 1st in this circumstance with 240v operation, and the first one was a failure within days of receiving it, same failure, but I don't believe it took anything out, that I can remember at least, so I'm hoping... I am running I believe 3-4 of them on different rigs, so my personally experienced failure rate is pretty dismal. Maybe I should buy a lottery ticket, since I'm so lucky? ;-)

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Message 1927370 - Posted: 30 Mar 2018, 20:18:47 UTC

The impact of a big bang failure of a PSU depends on what went bang. If its one of the switching devices then it is quite possible that everything downstream is OK, but if its one of the capacitors then it could be bad news.
The fact you've had two of these PSUs go bang then I'd be starting to think there's design issue. The rating of a component being marginal, probably a voltage issue. In one respect it is a shame that you have RMA'd this device because I'd love to be able to diagnose what was wrong with it. However I fully understand your actions, and the desire to get the computer working again quickly (and cheaply) is probably the most sensible to do in this situation.
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Message 1927375 - Posted: 30 Mar 2018, 20:42:27 UTC - in response to Message 1927361.  

Probably nothing downstream got hurt. A bang that sounds like a small firecracker is a MOV (metal oxide varistor) blowing up. It is the most common overvoltage protection component built into power supplies.

It sacrificed itself to protect the power supply. If you were to open up the power supply and shake it upside down, lots of little pieces of red or blue ceramic would fall out. It you look on the PCB, you will see two bare component leads sticking out of the PCB near the input power traces. That's all that is left of the MOV's. There would either be one or two devices in a power supply depending on whether they protected just LINE or Neutral also.

Have you checked your 240 line voltage with a meter? It should nominally read around 238 - 244V. But I have seen some "hot" 240V circuits where the line voltage was as high as 253V. That may be what happened in your case. I think most common MOV are only spec'd to 250V.
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Message 1927380 - Posted: 30 Mar 2018, 21:30:08 UTC - in response to Message 1927375.  
Last modified: 30 Mar 2018, 21:35:36 UTC

Yep, first thing I did was check it with a meter, it was at about 242-244v, so that shouldn't have been an issue I wouldn't think. And when I picked it up and shook it, there was a bit of rattling around inside there, I believe he mentioned that a cap may have let loose, but doing an over the phone internal diag based upon shaking is pretty much just a SWAG, so I don't think I'll put much stock into it.

It might've been interesting to open it up and see what went boom, but I am pretty sure that I would lose my warranty at that point, and even though I am not in a huge rush to get it replaced, it still has about 5 years left on a 10 year warranty, so I wouldn't want to replace that on my own, as it's about a $240 PSU new.

I'll see if I can shine a light into it and try to determine what blew without disassembling it. I plan on being back to the shop this evening, so I will be trying to power the system up with the other PSU, so I'll fill you guys in once I do. I'm surprised that the MOVs are only spec'd to 250V, that is only about 4% over it's rated capacity of 240v, but maybe everything downstream from there isn't designed to handle much more, so it was the sacrificial lamb in this case?

I wonder if there are any 240v 1ph UPS's out there (smallish ones and Reasonably Priced), that I could toss in line with them to hopefully help smooth out the transients and better regulate the voltages? I'd really only need 2 at this point to handle all the systems in there right now.

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Message 1927382 - Posted: 30 Mar 2018, 21:53:40 UTC - in response to Message 1927380.  

If you ever have had an electrolytic cap explode on you, you would remember. Instant aluminum confetti cloud all around you.

I don't know of any common 240V UPS solutions. Once you go 240V, the product is assumed to be server rack designs. The problem is the form factor. The 240V designs are 48V or 96V systems and that means minimum four 12V batteries and that means a big box. And not something consumer level cheap.
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Message 1927385 - Posted: 30 Mar 2018, 22:03:17 UTC

As Rob said, death on powerup would most likely be a failure in the primary section, the odds of damaging output from the secondary section are very remote (yes, it's possible. But very unlikely).

Here in Australia the nominal mains voltage is 230V -6/+10%, so it can be anywhere from 216 to 253V and be considered within acceptable limits. However the preferred operating range is -2/+6%, so approx. 225 to 244V. Even when we had a nominal voltage of 240V, once it hit 250V (which was within the allowable range) incandescent lamps had a tendency to die early & often and other devices weren't too happy either. A mains voltage that is too low isn't good either, as devices such as electric motors will draw significantly more current for a given load, and so run much hotter than they should.
For a 240V nominal supply, 250V or higher will lead to a early death of connected devices. 248V should be the maximum IMHO.


A bang that sounds like a small firecracker is a MOV (metal oxide varistor) blowing up. It is the most common overvoltage protection component built into power supplies.

That and it taking out the mains fuse. But that would only be the case if there was excessive mains voltage at the time you powered up. More likely is the failure of the chopper output device(s), as they experience their greatest currents when first starting up. Better quality switchmode supplies will usually have a soft-start circuit to limit the startup inrush current and prolong the life of the chopper output circuit.

I think most common MOV are only spec'd to 250V.

They come in a wide range of voltages, as well as current ratings.
For a 240V nominal mains supply, a 290V MOV should be used (to allow for supply variations). MOV provide protection against voltage spikes & surges (ie short periods of high energy), not just a high input voltage.
In most cases connecting the supply to a mains voltage that is higher than it can deal with will result in the mains fuse blowing. Over voltage protection while the supply is running is done through the design of the supply and would stop the supply from running till the mains voltage returns to normal, however in many cases it would come down to the mains fuse blowing due to the excessive current at that input voltage.
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Message 1927390 - Posted: 30 Mar 2018, 22:45:37 UTC

I've done a bit of searching on Fleabay, and yes, they are pretty much server grade kit at that point I've found. I won't be picking up a APC Back-UPS in that voltage, for certain. SmartUPS is pretty much it, and best I have seen is over $500. Ugh. Oh well, lets see what PSU #2 does, hopefully it's Much happier than the last one... :-O

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Message 1927428 - Posted: 31 Mar 2018, 2:27:18 UTC - in response to Message 1927390.  
Last modified: 31 Mar 2018, 2:32:42 UTC

For APC UPSs a 2200va is 20A 220 (some were available in 120V), I think the 3000VA were 30A.
Brain fart, I was thinking Amps at 120V input ... some would be available with 220V.
You should be able to find refurbished ones around as they are popular in server farms.
A refurbished 2200 is around $400-500 CAD, and the Smart UPSs are very reliable for failures, so I wouldn't shy away from refurbished ones.
They are also rebranded under other names, like Dell etc.
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Message 1927431 - Posted: 31 Mar 2018, 2:39:16 UTC - in response to Message 1927390.  

Al, I have a good opinion of TrippLite and also of this company. This 5000VA refurbed 240V UPS looks like it might fit your bill at a not too out of this world price. Tripp Lite SmartOnline SU5000RT3UPM UPS with BP240V5RT2U for $600
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Message 1927438 - Posted: 31 Mar 2018, 3:04:57 UTC - in response to Message 1927431.  

Al, I have a good opinion of TrippLite and also of this company. This 5000VA refurbed 240V UPS looks like it might fit your bill at a not too out of this world price. Tripp Lite SmartOnline SU5000RT3UPM UPS with BP240V5RT2U for $600

This is a nice piece of hardware.
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Message 1927441 - Posted: 31 Mar 2018, 3:31:19 UTC - in response to Message 1927431.  

5000VA UPSs puts you up to 30A 240V, he has 20A installed, which puts him down to 2200/3000 VA.
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Message 1927454 - Posted: 31 Mar 2018, 5:34:54 UTC - in response to Message 1927441.  
Last modified: 31 Mar 2018, 5:40:22 UTC

From what I can tell, the reason it is rated at 5000VA is that is has the auxiliary battery pack included. I think the native UPS is rated at 3000VA.

[Edit] OK, he needs to find this one. SmartPro 230V 3kVA 2.7kW Line-Interactive Sine Wave UPS
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Message 1927464 - Posted: 31 Mar 2018, 7:59:53 UTC

A few posts ago Grant wrote:
They come in a wide range of voltages, as well as current ratings.
For a 240V nominal mains supply, a 290V MOV should be used (to allow for supply variations). MOV provide protection against voltage spikes & surges (ie short periods of high energy), not just a high input voltage.

As someone else who lives in a "240V country" I would agree, a 250V device in the input chain is just too close to the limit on a 240V input. While the mains spec may say a 250V device is adequately rated it wouldn't take much of a surge to push the line voltage well over 250V - I've seen surges exceeding 300V during transients (which is well over the +10% limit).
I wish you all the best in sorting this out - given the way most PSUs are laid out it may be impossible to see waht's gone bang using a torch.
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Message 1927468 - Posted: 31 Mar 2018, 8:40:42 UTC - in response to Message 1927454.  

From what I can tell, the reason it is rated at 5000VA is that is has the auxiliary battery pack included. I think the native UPS is rated at 3000VA.

Nope.
The rating of the UPS is the load it can support. Units that can support additional batteries still have the same load rating, the extra batteries just allow them to keep running for longer once the mains drops out.
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Message 1927533 - Posted: 31 Mar 2018, 18:13:23 UTC

Thanks for all the suggestions guys. I think after looking around a bit, I am going go with this one: BRAND NEW APC Smart-UPS X SMX3000RMHV2 3000 VA Rack/Tower LCD UPC 2U 200-240 V as I spoke to the company yesterday afternoon, to find out more about it. My biggest concern is the age of the unit, because batteries lose their 'stuff' after sitting for a while, and in the past I've seen a number of these units on Ebay that turned out to be 'brand new' and actually still factory sealed in their box, but 3-5 years old, so pretty much the batteries would have to be replaced almost immediately. So in that instance, you would possibly be shelling out almost as much if not more, depending on the sale price of the unit and the # and type of batteries it has, than what was paid for the unit itself.

He said that these are supposedly new stock, but I will confirm this on Monday, and probably place an order for one, as that is a very good deal, with shipping included. Honestly, too good a deal, as my spidey senses are tingling, but if it turns out that it isn't what they said it was, they can pay to ship it back (ouch!) and give me a full refund. And yeah, it was about double what I wanted to spend, and even a few hundred more than the other suggestions here, but I have had some excellent experiences with APC in the not too distant past when it came to a warranty issue on a unit I had bought. They went so over and beyond my expectations, that I'm pretty much a customer for life, unless then somehow manage to mess it up, as companies sometimes have been know to do - new management, change of priorities of bottom line over customer satisfaction, that kind of thing.

it looks like I'm going to have to convert the plug ends on my 240v power strips from NEMA 6-15 to IEC320 C13. When I talked to him and asked him about the input and output he said 140 - 280V, IEC-320 C20 is in the input connection and output connections are IEC320 C13 x 8 , 1 x IEC320 C19. Have to verify with APC if the power cord has a NEMA 6-20 plug, as that is what I need to plug it into the wall and get the full 20 amps out of it.

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Message 1927725 - Posted: 1 Apr 2018, 16:28:06 UTC

Oh, and good news, I got it all hooked up with the new PSU, and it came up just fine, so all is good. Of course, that was when there were pretty much no tasks available, so when I left it running it was just idling, hopefully it will have some now when I go into the shop later today.

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Message 1927728 - Posted: 1 Apr 2018, 16:36:48 UTC

Wow, that's good news indeed, Al.
Dodged a bullet on that one.
Happy is the person who shares their life with a cat. (Or two or three or........) =^.^=

Have made friends here.
Most were cats.
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Message 1927729 - Posted: 1 Apr 2018, 16:59:09 UTC - in response to Message 1927728.  

Whew, no kidding! I was having visions of having to have 'discussions' with EVGA about any non-EVGA parts that might have been taken out when it blew. I have to say though, that booting up and idling is a bit different than going full bore 24x7 crunching, so I reserve the right to withhold judgement for a bit, but all signs so far are looking very hopeful!

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Message 1927735 - Posted: 1 Apr 2018, 18:17:40 UTC

Great news Al.
Could you try and find out from EVGA what went bang - engineer's curiosity running at this end
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Message 1927738 - Posted: 1 Apr 2018, 19:34:18 UTC - in response to Message 1927735.  

Sure, I will put a note into the box when I pack it up and send it back, asking if they could fill me in with that info and email me back. Not sure if they'll care enough to actually do that, or even if they do the repairs there or send them overseas, but I will certainly try.

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Message boards : Number crunching : Taking odds that a system will boot up w/o issues after a big boom


 
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