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PC Not Booting Until a Different Phase is Used?
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."
We had a customers Gateway machine that often did that exact same thing. Machine would refuse to boot or crash at the BIOS with invalid memory errors. Swapping the outlet to a plug across the room would cause the machine to boot just fine and stay running for months on end. Even moving the plug back to the original outlet would be fine for a while. The kicker is, it wasn't just the computer. Plugging in his palm would cause the palm to reset while sync'ing and glitch during regular use.
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.
Why do overlook and oversee mean opposite things?
"Mystery Problem: When the power glitches"....
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.
Modesty is one of life's greatest attributes
Test the ground line on the power strip.
There should be some kind of inline tool that measures the 'quality' of the power coming from the line and flowing into devices. It could have like 5 levels or so and you could check the outlet for problems during real-time use. It could have a bunch of different functions, you know, like checking for electrical problems at the same time.
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.
Job? I don't have time to get a job! Who will sit around and bitch about being broke and unemployed then?
Seems that every computer connected to this old Thinnet network would eventually fail, either the motherboard or the network card. I found out the hard way if you grounded yourself to the case you got a good 70vAC shock!!
:-)
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
Si vis pacem, para bellum! For evil to succeed good men need only do nothing!
(Or some other kind of scarlet swimmy thing...)
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.
If you opt to test the outlet with an O-Scope, first find out if the ground pin on the cord is tied to the ground on the o-scope inputs and chassis! Most analog, corded models are and you run the risk of putting 120-volts on the chassis or shorting the outlet through the o-scope. More than a few amateur electronics techs have missed this feature and blew up an o-scope or shocked the hell out of themselves. Electronic techs often use isolation transformers to protect the equipment and themselves for this reason.