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14300
December 31st, 2008 03:00
Precision 470 Shuts Down & Restarts at completely random intervals.
This 470 machine which has been performing well up to now, has begun shutting down and restarting again at random intervals, in a similar manner to that described in another thread found here: http://en.community.dell.com/forums/p/19247423/19391560.aspx#19391560 .
The machine shuts down so quickly that no record or sequence can be found of the incident in either the OS event logs, or BIOS log.
The machine will usually post correctly on startup and go on to load the OS (Vista) and when it does this everything is fine and it works as well as it always has.
Then, at a random interval, but frequently associated with a command from keyboard or mouse to begin a task for example opening MS Outlook, the screen goes blank and the machine dies instantly. All fans remain turning operational lights remain lit, and all power rails are present.
The machine will then after a random period of time restart itself again, as if it had been deliberately switched off by the operator.
This random shutdown symptom can also manifest itself during onboard diagnostic testing (Dell F12 function). However when the machine stays up long enough to complete the full suite of diagnostic tests, everything checks out as being 'ok'.
The machine randomly shut itself down during an Acronis image recovery exercise immediately prior to the recovery sequence.
When the machine does post/boot properly it works perfectly, it is/was an excellent workstation, and doesn't present with any faults associated with incipient HDD failure or any other symptoms associated with known fault sources.
Having Googled the symptoms I found this http://www.badcaps.net/forum/showthread.php?t=5974
However, having been in the business for sometime I am wary of Self Deluding Diagnostic Process Syndrome.
I would be grateful for any advice that might be around the forum, many thanks to you all.
JohDeP
4 Posts
1
January 6th, 2009 08:00
Precision 470 Shuts Down & Restarts at completely random intervals. Precision 470 Motherboard capacitors.
This problem is now solved.
The problem lies in a faulty batch of capacitors that were installed on a limited number of Precision and Optiplex Motherboards.
The capacitors seem to be unable to cope with the thermal stresses imposed upon them in their installation location, around the processor; and the endcaps of the capacitors separate from the dialectric 'sandwich' inside the component resulting in an open circuit capacitor. It doesn't help that when the capacitor cools down again the end cap contracts onto the dialectric sandwich resulting in a functioning capacito
The faulty capacitors are marked on the topside of the can with an X, if you have ones marked with a K you are probably ok.
lanthonyneville
6 Posts
1
February 22nd, 2009 06:00
Hi JohDeP. I am having the same problem with my 470 and have read a lot about the capacitor problem you mention. My PC has started shutting down on its own and the status lights indicate "VRM 0 failure". But there seems to be no removable VRM on the board. Were you able to replace just a part, or was the only way to fix it to replace the whole board?
One last question - I read that Dell brought out a motherboard with better capacitors to replace the faulty models. Do you know the part number of the new board, as if I need a new board I'd like to get this one?
Many thanks for any help you can provide.