PC Not Booting Until a Different Phase is Used? 130
2by4 asks: "I run at IT Dept for a small firm, our network room houses production &
development servers. Some machines are plugged straight into a strip with
no UPS. Here is the Mystery Problem: When the power glitches, the strip
machines go down, and some of these machine WILL NOT come up again until I switch
them to a new outlet. Once this happens, I can put them back on the original outlet
and they will work. Unplugging & replugging on same outlet is not enough. I have seen this on at least 5 machines so far, with independent confirmation. We can narrow the 'fix' to plugging into an outlet of a different phase (there are 3 separate 120v phases powering the room). The symptoms vary from no powerup, to frozen at the BIOS (depends on motherboard make), etc, but consistently, switching to a new phase fixes them. I tried the 'unplug-wait-&-replug' cycle, to no avail. Using a new outlet w/ a different phase is the only solution. Any theories? I assume the new phase is causing something to 'reset', but what? I can provide more details, but I am wondering if anyone has seen this before? I am completely and absolutely stumped. Our power is healthy, lightly loaded, evenly distributed and the power strips are new. I know I should have at least a simple UPS, but this mystery is causing me to lose sleep."
Hmm (Score:5, Insightful)
Obviously, I mean that you should do this with the plug UNPLUGGED.
Re:Hmm (Score:3, Informative)
I generally have the same problem with this entire scenario. If the equipment is designed to work on one phase, once it is disconnected from the wall, how does it keep track of exactly where the sine way should peak? The only thing I can imagine is that there is a battery driven oscilllator whose phase is s
Re:Hmm (Score:2)
Not if there are two capacitors, one on each phase. One might be in a charged state while the other is discharged, that would allow the two states to be distinguishable. It would also depend on the exact moment that the power got dropped. A diode would probably have to be involved somehow. But this is just a
Re:Hmm (Score:1, Informative)
Re:Hmm (Score:2)
Now as for 2by4's problem:
Sounds like you have some bad power supplies that are acting up. It is a possibility that that particular phase might have noise on it or "dirty power" caused by other equipment or wiring problems. Some buildings have 277/480 mains(or sometimes in canada 346/600) and then have seperate stepdown transformers throughout the bu
Re:Hmm (Score:4, Informative)
Re:Hmm (Score:2, Informative)
I'm not an EE (and only have the absolute basic knowledge of electronics), so I can't really meaningfully elaborate further.
Re:Hmm (Score:2)
And an inductor and a switching transistor. I'm not ignorant.. Even built one, once. I was guessing that this particular supply might have some extra circuitry between the wall and the rectifier, possibly for cleaning up the AC waveform. Again, it's a wild-assed guess. Other people have put forth more likely scenarios, involving faulty grounds.
Hmm-Willy Watt says... (Score:1, Funny)
Man! You're just trying to take all the fun out of electricity, aren't you?
Re:Hmm (Score:2)
When you move them across the room, you've given them adequate time to discharge, and they will power up.
Try waiting for a longer time before plugging it back into the same outlet. I doubt it's the outlet/phase wiring. I think the culprit is your PC PSU's.
Gateway's were notorious for this - leave them unplugged for a period of time, and they would s
Try troubleshooting not fixing. (Score:2)
Healthy != glitchy If you had healthy power, you wouldn't be losing it.
It sounds like this only happens when you lose power. Correct? Is it a blackout, glitch, or brownout?
You have 5 computers that display these symptoms. What do they have in common?
Same circuit? Same powerstrip? Same outlet on strip? Same model of server? Same PSU? Do you put the problem computer bac
Re:Try troubleshooting not fixing. (Score:2)
I think maybe instead of "healthy", what he meant was "clean", which IIRC is largely related to the purity of the waveforms, which can be quite separate from problems of power loss.
Re:Hmm (Score:2)
Thanks for the tip!
CB (Score:4, Insightful)
Re:CB (Score:2)
Try resetting the circuit breaker on your "strips".
Only useful if it "trips." :-)
Gateway (Score:4, Interesting)
Our Fluke meter showed nothing special on the line and an APC UPS showed no spikes nor higher than normal voltage levels.
To this day we call it the haunted outlet and tend to just keep things away from it.
Re:Gateway (Score:2)
Having trouble with the Palm also makes a pretty strong case for it being the outlet or wiring to it. Try replacing the outlet and check for tight connections on it and all nearby outlets.
There are a number of local problems one can have with power, in addition to those coming in from the outside world.
1) low-voltage condition under load
If there is a high-resis
HUH??? (Score:2, Interesting)
then you say:
"Our power is healthy, lightly loaded"...
Not contributing to the solution of your problem, but my office doesn't get "regular" giltches like yours seems to, even though our power is "healthy" too.
Sounds like you need to call your power company.
Re:HUH??? (Score:3, Insightful)
More likely a competent electrician, if some of the outlets are fine and some aren't.
As an EE student, my professional opinion is: (Score:5, Funny)
(Flunking, in case you couldn't tell)
Re:As an EE student, my professional opinion is: (Score:3, Informative)
Re:As an EE student, my professional opinion is: (Score:1, Funny)
Wikigremlins (Score:2)
Anyway, Gremlins only fiddle with airplanes.
Re:As an EE student, my professional opinion is: (Score:2)
It's not GNOME (Score:1)
Gnomes?
KDE would have the same problem.
Bad ground (Score:2, Interesting)
Are you sure your power is all the way recovered? (Score:5, Insightful)
We are a light industrial building in a heavy industrial park, and I swear the power goes glitchy 2-3 times per year.
We'll get brownout and blackouts, and when the power comes back it SEEMS like it's on, but only 2 of the 3 phases of the A/C actually comes up, meaning (depending on how it's wired at the *circuit box*) some circuits are dead, some are full, and some are semi-brownout (our flourescent ballasts LOVE that half-state.....not).
That third phase sometimes doesn't come back up for hours.
I have no idea if this is of any help, that electrical stuff is arcana to me, I'm just reporting what we've discovered.
Re:Are you sure your power is all the way recovere (Score:2)
Re:Are you sure your power is all the way recovere (Score:2, Informative)
Re:Are you sure your power is all the way recovere (Score:2)
Re:Are you sure your power is all the way recovere (Score:1)
Also, if you are in the US, you've got single split phase. If you're in Europe then you have two phase. Are you sure your parents have two phase? How much do they pay for that?
Re:Are you sure your power is all the way recovere (Score:2)
In Oregon, two phase is common (I know, I use X10 in my house, and have problems with the 5v powerline commands getting from one phase to the other). Two 110V wires coming in from the transformer. In the case of the X10 problem, a simple capacitor across the phases (passive coupler in a box behind my dryer- one of the few places I
Re:Are you sure your power is all the way recovere (Score:2)
Are you sure? My understanding of the way brownouts kill equipment is that P=VI so if V drops, I increases, and the wiring is not of a heavy enough gauge to handle the increased amperage so it burns out. Shouldn't this happen in your stove, too? (Obviously, IANAEE.)
Re:Are you sure your power is all the way recovere (Score:2)
Re:Are you sure your power is all the way recovere (Score:2)
Re:Are you sure your power is all the way recovere (Score:2)
Um, Wrong.
We definitely have the power, it may not be universally connected residentially.... If you have 220 in the house (typically for an electric stove or a clothes dryer), you have two phase coming in from the street.
You may also have multiple phases coming in if you have a higher load. This office is that way.
The multiple phases may not be wired, but they are definitely available. I looked into setting up a 3-phase circuit t
Re:Are you sure your power is all the way recovere (Score:3, Informative)
Not really. House 240V power is created by connecting one phase of a three phase feed to a transformer with a center tapped output. The center tap is grounded and voila, you get split phase 240V power. It consists of a ground, plus one leg at +120V and the other at -120V, referenced to ground of course. Take the potential across the two of them and you get 240V. While these legs ar
Re:Are you sure your power is all the way recovere (Score:2)
Re:Are you sure your power is all the way recovere (Score:1)
Check Wikipedia.
Re:Are you sure your power is all the way recovere (Score:2)
The true Mystery (Score:2, Insightful)
I think starting the article with "We have since gone out and bought some fairly inexpensive UPS's to eliminate this problem but nonetheless the phase detection has piqued my curiosity
Your power supply's doing its job. (Score:2, Informative)
This Post Needs More Attention (Score:2)
My first reaction to the parent question is what do you mean by "different phase." Do you mean your server room is fed off of 2 or 3 phase power? And that some outlets are fed off of different branches? Or do you mean you change to a different circuit?
What is likely is that certain voltage rails aren't settl
Re: (Score:2)
What Would Jordi Do? (Score:4, Funny)
Re:What Would Jordi Do? (Score:2)
the problem is really in the flux capacitors.
Re:What Would Jordi Do? (Score:1)
Re:What Would Jordi Do? (Score:3, Funny)
Alternatively, try modulating the frequency of the deuterium drive. If that fails, try reversing the polarity of the neutron flow--you'll need a sonic screwdriver (like $10 at Home Depot/Lowe's). If that fails, your dilithium crystals are probably dead and you'll need to find replacements (should take about 60 minutes, minus commercial breaks--you'll need someone in a red shirt to help you, best if it's not a close friend).
Try a voltimeter (Score:1)
Re:Try a voltimeter (Score:1)
We were having brown outs a few years back and my PC ran just fine with no glitches, even when I measured voltages as low as 90 volts.
Not to say that more robust server class machines will do the same, but I imagine at least some of them will... especially for the varying definitions of what class of hardware belongs in a machine room.
-Steve
Re:Try a voltimeter (Score:2)
The thing is, when a power supply is running on low voltage, it has to make up for the lacking by drawing more current. This also stresses the power supply components as they have to do more work. Many power supplies will not o
Check the Neutral To Ground (Score:5, Informative)
We had the original electrician who installed the line back out to test. His voltmeter was showing about 20-30V between the neutral and ground. According to code (IANALE), these lines are supposed to be connected at the panel. Apparently without this connection, the two sides coming off the transformer can float in the voltage which may have been responsible for the light bulbs blowing. Once the neutral and ground were connected, the wiring fault light went out on the ups and everthing has since been fine.
SHORT RESPONSE: Have a licensed electrician check out your circuits.
Re:Check the Neutral To Ground (Score:5, Insightful)
I actually worked on a system where printer interfaces were burning up because an electrician had reversed neutral and ground in the outlet where the printer was plugged in. There was enough of a difference between neutral and ground to damage the interface of the computer.
Re:Check the Neutral To Ground (Score:1)
Re:Check the Neutral To Ground (Score:2)
I found this indespensible when I was shopping around for a house - you never know what you will find in a house that has bad wiring. Always bring a tester, can sometimes save you from wasting money on a home inspection.
Re:Check the Neutral To Ground (Score:2)
Re:Check the Neutral To Ground (Score:2)
Re:Check the Neutral To Ground (Score:2)
Re:Check the Neutral To Ground (Score:2)
Re:Check the Neutral To Ground (Score:3, Informative)
Depends on what you mean by panel.
The "ground" (the green or bare wire, which under normal conditions carries NO current) and the "neutral" (the white wire, which DOES carry current in a 120 Volt circuit and should be assumed to carry current in all others for safety's sake) must be
Re:Check the Neutral To Ground (Score:2)
SHORT RESPONSE: Have a licensed electrician check out your circuits.
Absolutely! By doing that, you found and fixed a genuine safety hazzard.
ALL devices and connections to the same ground (Score:3, Informative)
Printers must be connected to the same ground, for example. Check the integrity of the ground; their should be low resistance, as measured with an ohmmeter after you have turned off the power, of course.
Also suspect that there is some weird voltage riding on the power. Is your power clean? The only way to check this is to look at it with an oscilloscope. Oscilloscopes make an instantaneous on-screen graph of the voltage.
All computers should be connected to battery backup power supplies, too of course.
Re:ALL devices and connections to the same ground (Score:1)
Re:ALL devices and connections to the same ground (Score:2)
Certainly all computers must be plugged into a battery backup power supply. The loss of data is far more expensive than the $20-after-rebate cost of a UPS. If Windows XP writes garbage to its registry file, it can be impossible to recover cheaply.
Sometimes PC power supplies don't reset from an error condition until they are unplugged for a minu
Re:ALL devices and connections to the same ground (Score:2)
Nope, no exception. It's quite important to make sure equipment connected via electrical ethernet has common ground.
Re:ALL devices and connections to the same ground (Score:2)
Re:ALL devices and connections to the same ground (Score:2)
The last time this happened, I disconnected the PSU from the mains and the motherboard and reluctantly started stripping it for parts. Whilst removing the AGP graphics card, the motherboard-mounted LED to warn that the motherboard still had power started flickering on and off (eek!)
I hurriedly started yanking
Phase balance? (Score:4, Informative)
Just Happened to Me (Score:3, Informative)
Re:Just Happened to Me (Score:2)
If it gets really bad, and a different HD doesn't fix it, there's someone who repairs them as a business who's on avsforum all the time, and also sells
Get at least a cheapo UPS (Score:2)
However, it does sound though like you need to get someone competent to check over the electricity supply. I'm not, and neither are you. I'm assuming that you're in the US (from the 120v comment) and I'm s
Re:Get at least a cheapo UPS (Score:2, Informative)
This happened to me once (Score:1)
Me too... with AC adapters (Score:2)
Ultimately, both of them quit working altogether. IANA[electrician] and she didn't feel like hiring one, so I just got her another adapter and she
Re:Me too... with AC adapters (Score:2)
Drain the Power Supply safely. (Score:5, Informative)
1) Unplug the Power supply.
2) Hold down the power button (on the front) for 10 seconds.
3) plug in the power supply
4) Turn on the computer.
I solve this issue with most of my systems by connectiong them to a UPS. Some crash on their own so often that they're not worth a UPS.
Re:Drain the Power Supply safely. (Score:1)
Here at work I have noticed that when some older IBM machines don't power on properly..
I unplug the power cable from the back of the machine and wait 30 seconds, the power supply makes a kind of discharge sound which hard to explain but you'd know it if you heard it.
Then we just plug the power cable back in and the machine powers on without delay
Re:Drain the Power Supply safely. (Score:1)
Sounds like it could be a grounding problem (Score:4, Insightful)
Some other things to check:
The continuity between the outlet and the electrical box (all three wires).
That your grounding rod is correct for the type of soil in you area.
A different power supply.
Also, like a previous poster noted, try shorting the input to the power supply (when it is unplugged), that may give you a temporary fix.
O-Scope Warning !!!! (Score:2, Interesting)
Re:O-Scope Warning !!!! (Score:2)
Also note that oscilliscopes typically have very high-impedance inputs, that will work perfectly well with some megaohm resistors in series with the test leads. Worst case, it may show a lower amplitude wave, but the waveform will be preserved. At 377V (peak to peak voltage for 120V RMS), the most current you can pump through a 1 megaohm resistor is 377 microamps, which should be safe.
And of course, make sure
Grounding problem and testing (Score:3, Insightful)
Merlin.
Bad Power (Score:3, Interesting)
Unclean power is the problem that causes more crashes than people would like to admit. I've had my parents on the other side of the house start a vaccum cleaner and I've bluescreened at the same time..quite a few times..before. Obviously not a coincidence.
Re:Bad Power (Score:4, Funny)
Obviously, your electrical system can only support a finite amount of suction at a given time. Consider switching to an OS that doesn't bluescreen ;)
I have the same problem with a laserjet 4000 (Score:2)
I had a weirder one (Score:1, Interesting)
After a bunch of head scratching I tracked it down to one PC plugged into a floor outlet. Seems the outlet was cracked and had a carbon trace from the Hot to the Gound on its face. Got 4 year support contract with an AZ tribe for finding that one
Re:I had a weirder one (Score:1)
Evil Ground Loops... (Score:2)
I'd look into the docs on the UPS you have to see if there is a way to hook up a ground lug on the *output* side of the UPS to tie it to building ground. I'd also get one of those testers over at Home Depot to see if your outlets are all actuall
The List (Score:4, Informative)
2) Bad neutral on one or more phases.
3) Voltage drop on one or more phases.
For the first three get an electrician out, don't mess around with three-phase power.
4) Electrical noise on one or more phases, this may not be caused within your computer room.
5) Equipment connected on different phases affecting each other, for example a printer on phase A and a server on phase B.
6) Borderline power supply in a machine affected by one or more of the above conditions.
7) Faulty power strip(s).
8) Incorrectly wired plug(s) or socket(s).
Ed Almos
Use a power quality monitor (Score:1)
not phase, but ground? (Score:1)
I would venture that the problem may be a bad ground on one circuit. I have seen problems where a computer plugged into a peripheral, say a printer, would crash if the peripheral was on a different power circuit, due to a problem with ground and neutral not being connected (or something like that).
It's been a long time since high school electronics, but I could see a grounding-related problem more simply than a phase-related problem.
Ground Problems (Score:2)
Is the computer plugged into anything else when it's being glitchy? Printer? LAN? Modem? It may be that there's a difference in ground potential between the computer and the peripheral that's causing a current flow between the two.
If not, ignore the above but check the grounding anyway.
Is the phase thing a red herring? (Score:3, Interesting)
Turning off and on at the same mains outlet will generally be "off, count 10 elephants/mississippis, on". Moving outlets usually involves physically moving the damn thing around, or unplugging a wire from one socket, taking the wire across the room and plugging it in somewhere else. Consider the time it takes to do this - could the power-off time be the significant factor, and the phase thing is a coincidence?
Or on a similar theme, how about disconnecting the mains cable (and waiting some time) so that the mobos are fully powered down? That happens naturally when you disconnect the cable and plug it in somewhere else. Maybe try repeating the same action, but on the original phase.
Not to doubt the fault-finding you've already done, but just adding a bit of devil's advocacy to suggest possible alternative situations with the same symptom.
Grab.
Solution. Wired wrong (Score:2, Insightful)
1: You have poor to non-existent grounds on one or more of the phases. This can be tested for by the electrician.
2: The HOT and Neutrals are swapped around and generally this isn't an issue except that *modern* power supplies are getting cheaper and cheaper and this usually means cutting out *some* parts like full-wave bridges for half-wave diode sets, and similar tricks. This then
Might be due to current leakage or stray EMF (Score:3, Insightful)
Most commonly, when plugged into a peripheral or another device which is separately powered or grounded.
What was happening was small amounts of current leaking in through peripheral components was affecting the power supply... Usually to stop them starting up. ie, hit the power button, no start, no lights. The leakage was in the micro-amps region, but was enough to leak back through the motherboards into the power supply, and cause a false fault condition reading on start up, and the PSU would shut down before it got started.
The solution? In one instance, I decoupled the power rails. In another, better grounding. Another? Changed phase. The best solution was usually to find a better power supply that wasn't affected, but was not always possible.
Often in these circumstances you can feel the current leakage, as it's often at high voltage but very low amps. Sometimes it feels like a slight tickle when you touch rivets on the case.
Additionally, I've also encountered similar problems due to engineering faults, where a high impedance section of the circuit was acting like a radio antenna and was getting enough "reception" of a local signal (any strong electromagnetic radiation source) and causing a fault condition on power up that was not present during normal operations (when the applied signal was significantly stronger than the picked up signal).
Solutions there include EMF shielding and redesigning the circuits.
Problems like this are difficult to diagnose, as they are not always obvious, and there is very little you can do to test or troubleshoot directly. Often it involves experience and a little lucky guesswork.
GrpA
At pixelvision we always blamed (Score:2)
What I would do is go to my toolbox and get my $2 outlet tester and bring it to work the next day. If that turned up nothing, I'd go with an exorcist.
Ice Cream (Score:1)
You seem to have focused on the phase of the circuit the same way the driver in the story focused on the flavor of the ice cream. Try to think of your problem more in terms of the facts, and less in terms of your hasty conclusions.
-Peter
I have had the same problem (Score:2)
voltage between grounds at different outlets (Score:3, Insightful)
There are two ways this can happen:
Note that this can be induced in otherwise properly bonded circuits by the use of daisy-chained power strips/bars. It is the act of plugging in a (typically high-power) item on the end of the line (so the draw through the whole line is high) and connecting it via a signal cable (Ethernet, serial, USB, etc.) to something plugged closer to the junction box (electrically) that then ends up routing some of the ground current through the low-voltage signal line.
In general, the cure is to return to the bonded-circuit of yesterday designated by the orange plugs where they've been installed. These consist of a single plug per circuit (never more than one!) where ground is bonded to neutral at the connection box so there is no possibility that there may be a voltage drop due to current between individual recepticals.
We seem to have gotten away from the specification and use of these (more expensive to install) power recepticals. I for one continue to specify them for most commercial installations and have yet to see any of the kinds of things mentioned here when they have been properly installed and used.
The worst case I saw of this was in an office that was long and skinny in a brand new building (they were the top floor) with retail below. The office went in first, and the retail later proved to include a dry-cleaner that used quite a bit of power off two phases of the 3.
A Unix computer in the center of the long office fed dumb terminals the length of both directions. The reception area was the farthest out - about 100' by wire - RS232 shield.
The terminal at reception kept doing wierd things: hanging, mystery characters, and in fact died - 3 times! Lights on but nobody home!
It turned out the serial interface was dieing - due to about 5 volts between ground and neutral which was pulling current through the cable's cladding and buring out the chip. The electrician poh-poh'd it saying "5 volts on a 120volt line was nothing to worry about" but in fact it was 5 volts on a 12 volt circuit and carried current in what should have been a voltage (high impedance) system. No wonder the interfaces were flaky and buring out.
Replacing the power plugs with "home-run" single bonded ones fixed the problem.
Check the Label (Score:2)