My workstation started acting oddly at the end of May signalling memory errors during boot-up. Obviously as a technically minded person I tested the memory, and as there was nothing I could find, I sent an e-mail to Dell. They replied, and as the problem hadn’t re-occurred I ignored it until last week, when my PC started rebooting all of a sudden without warning. After this happened a second time I was getting concerned.

I spoke with Dell Technical Support who asked me to through various bits of diagnosis. I had by this time swapped out half the memory at a time to make check it wasn’t anything simple. They were going to get me to re-seat the voltage regulator module (VRM) as this was one of the error codes displayed on the chassis during problems (Dell systems have green/orange lights with A B C D written on them to indicate what the problem is if the system can’t tell you on the monitor), but in the end they asked me “Do you know what a capacitor is?” which I found a bit odd. I replied “Well I’m not an electrician but yes I know what they look like”.

They asked me to see if the capacitors were ‘flat’ or bulging out. At first I looked at them and they looked normal, but then looking a bit more closely, I thought they were slightly rounded at the top:

This is what they should look like (from a system with a similar motherboard):

I felt a bit nervous saying categorically they were bulging out without comparing them to another system (the second picture) but the Dell engineer was very confident that the motherboard needed changing the following day. And indeed, following a very courteous visit by a Dell engineer, the problem has been fixed with the replacement motherboard.

The 3-year warranty will be running out in just over a couple of months, so a new system may be needed soon

There is a Wikipedia article on Capacitor Plague that explains this phenomenon (thanks John!)