- Symptom
- Powers on and fans spin, but the screen stays black and the machine never reaches startup.
- Checked
- Power supply voltages under load, memory one stick at a time, graphics card in another system, CPU socket under magnification.
- Finding
- Two bent socket pins left over from an earlier cooler swap, plus an intermittent memory slot.
- Repair
- Pins realigned, board kept in service, thermal paste renewed, memory moved to a good slot.
- Result
- Passed a four-hour stress test with stable temperatures.
Example of how we document a diagnosis.