Thank you for reading this and I know that this a vague  question but you may be able to give me a lead. For the past  couple of days my desktop computer has been very slow to begin the boot process, perhaps 5 minutes or so. Now it won't boot all. The disk activity led blinks at about a 3 second rate, the fans run, and speed up once the system warms, and I can measure 5 and 12 volts at the disk drive. There is no video from the on-board video chip (which is normal until the system boots up) and the system won't boot from the cd drive either. I've reseated various connecters and the ram board. So, the power supply and disk drive are propably ok which leaves the mother board, ram and cpu but how I determine which one is at fault? I'm at least a 1000km from civilisation so I cannot speak to service personnel. 
Sent from Samsung tablet. Regards, Phil
Phil 's gravatar image asked Mar 17 2017 at 16:54 in Ubuntu-Users by Phil

3 Answers

On Friday 17 March 2017 19:54:56 Phil wrote:
> Thank you for reading this and I know that this a vague  question but > you may be able to give me a lead. For the past  couple of days my > desktop computer has been very slow to begin the boot process, perhaps > 5 minutes or so. Now it won't boot all. The disk activity led blinks > at about a 3 second rate, the fans run, and speed up once the system > warms, and I can measure 5 and 12 volts at the disk drive. There is no > video from the on-board video chip (which is normal until the system > boots up) and the system won't boot from the cd drive either. I've > reseated various connecters and the ram board. So, the power supply > and disk drive are propably ok which leaves the mother board, ram and > cpu but how I determine which one is at fault? I'm at least a 1000km > from civilisation so I cannot speak to service personnel. > > Sent from Samsung tablet. > Regards, > Phil
This isn't much to go on, but as a C.E.T., I'd be looking at the tops of the electrolytic caps on the mainboard, particularly those right near the cpu socket, looking for bulged or even open cracks in the safety scratches in the aluminum on top of them. I'd also open the psu and look at the caps in it, again looking for bulged or vented tops. This would be a sign of the capacitor in a switching circuit, and these all are, of excessive ESR, Equivalent Series Resistance. PSU's of more recent history than 10 years, seem to have a built in voltage fade with time, and the 5 volt line, if below 4.75 to 4.8 volts when first turned on, will hold the cpu in reset until the voltage gets above 4.8 as these caps warm up, but eventually the ESR causes so much heating they will vent and its game over.
What you do next depends on the soldering tools you have, and a src of spare capacitors to install. Lacking those, you may well be out that 1000km drive back to civilization to just upgrade to fresh stuff. Even with a hot air rework station, its hard to change the motherboard caps because the pattern on the board is big and fat so it can serve as additional cooling heat sinks for the caps, so you really have to turn up the heat and potentially cook the board just to get the old ones out.
Thats my best shot at it, based on 65 years of chasing electrons to make them do usefull work. Best of luck guy.
Cheers, Gene Heskett -- "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Genes Web page <http://geneslinuxbox.net:6309/gene>
-- ubuntu-users mailing list Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-users
Gene Heskett 's gravatar image answered Mar 17 2017 at 17:26 by Gene Heskett
Oops, somebody already mentioned clearing the BIOS, too :).
I'm pro troubleshooting by beeps, too, but often manuals don't mention
the beep code.
ubuntu-users mailing settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-users
Ralf Mardorf 's gravatar image answered Mar 18 2017 at 00:31 by Ralf Mardorf
Did you measure under load?
There should be the "ok"-beep. No beep at all most likely is already a
signal for a failure.
ubuntu-users mailing settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-users
Ralf Mardorf 's gravatar image answered Mar 18 2017 at 03:18 by Ralf Mardorf