A friend of mine gave me a dead Dell Latitude D600 to look over in the hope that I could revive it. The symptom was that it wouldn't power up.
Well it did power up for me on my bench and I proceeded to update the software and clean the disk. Then the bug struck: pressing the power button would only cause the LEDs to flash rapidly for a few seconds and the machine would sink into inactivity again.
A dead clock battery can cause this because the CPU has no source of timer events for the BIOS code. Fortunately in this model, the clock cells are very accessible. I measured the three of them and their voltage was well above the 7.2V required. So that wasn't the problem.
So I did a search on the Internet and found this page on FixYa. The top solution was to depress F7 and F8 while booting. I was skeptical but it was simple to try. Lo and behold, the machine fired up. Apparently this model experiences a lot of contact problems with the BIOS chip which is just underneath F7 and F8.
The owner told me that a repair shop had assured him that the machine was beyond repair. Maybe they need to be told about this thing called the Internet.
