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So I set up a desktop computer running ubuntu in a classroom that was running through an AVR at 220 volts. I got a report that it wasn't working, so I came to look at it, and sure enough, fans and lights would go on, but the screen would remain blank.
Then I realized somebody had plugged it into 110 volts. I plugged it back into 220, and ta-da! it boots. However, everything you do is extremely sluggish, be it opening an app, a folder, animations that should play when moused over, etc. I ran an hdd test, but the results came up fine. The PSU is also outputting the right voltage on all lines as tested by volt meter. What is the problem?
I remember having this happen with one other computer, but i quickly realized my mistake, and after plugging it back into 220 it worked fine. It could be that this one was a longer duration of incorrect voltage.
So anyway, any help to identifying the problem would be greatly appreciated.
edit: example of slowness: it takes 8 seconds to open a folder containing 1 item
-it takes about 10 seconds to open the shut down dialogue box, and about 1 more minute for pressing "shut down" to actually get rid of the box
Is the computer's PSU an automatic switching model or does it have a manual switch on the back for changing voltage? If it's not auto switching and it got the wrong voltage then I would expect it to either shut off or go bang. Try checking your CPU status to verify clock/voltages using I-Nex or something similar in case something screwed up the BIOS and caused it to underclock. – James P – 2015-01-13T10:08:36.110
1In fact, you could try just restoring the BIOS to defaults to be sure. – James P – 2015-01-13T10:14:46.050
the psu has a manual voltage change. Yet as i stated, it is still working fine. It was set to receive 220 volts, but got 110, so I think going lower did not damage it. Higher, yes, It would go bang. In the Bios the clock is the same as before, so that looks fine. – Blaine – 2015-01-13T10:16:25.213
oh, good idea, I will reset bios to defaults now – Blaine – 2015-01-13T10:17:04.883
resetting bios to default did not help. However, I did notice that there are only 256 mb of ram, where I thought I had 500. I will try re-seating the ram, but I still wouldn't expect such slow performance from just lack of ram. – Blaine – 2015-01-13T10:26:48.393
Perhaps the RAM was damaged by the voltage issues? If one of the sticks is no longer registering, perhaps the remaining one has problems too? You could try MemTest86 to check for errors, although you would probably have seen kernel panics by now if it was the issue. – James P – 2015-01-13T10:35:43.193
Ok, after ram is re-seated, the 512 mb is correctly registered in BIOS, however, the computer is still sluggish. Interesting note: Boot time is still normal. – Blaine – 2015-01-13T10:37:42.347
1Have you checked the temperatures? I'm wondering if someone was messing around with it for a laugh, and as well as plugging it into the wrong voltage they did something else like loosen the heatsink or stick something in the fan to stop it turning. That could cause extreme slowdown. That I-Nex program I mentioned could be useful for checking. – James P – 2015-01-13T10:40:25.980
Some of the people in this school have never touched a computer before, so I doubt this would be the case, especially since the bios gives a warning when somebody has opened the chassis. – Blaine – 2015-01-13T10:41:55.543
Wait... IT WORKS NOW!!!! Either re-seating the ram or resetting the bios or a combination of both helped. Thank you! – Blaine – 2015-01-13T10:44:57.987
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Thank you, you have just helped put Leonard back in a classroom https://sites.google.com/site/techforteachinghome/leonard
– Blaine – 2015-01-13T11:01:01.467Glad I could be of help. Hope 'Leonard' behaves himself in future :-) – James P – 2015-01-13T12:34:42.573