When working with a "dead" PC the technician needs to start by making a general assessment of the nature of the problem. A "dead" PC falls into basically 3 categories: "No LEDs, no sounds", "Some LEDs, some sounds", "Full LEDs, full sounds". In the first category, power is the primary suspicion here from the wall to the motherboard. In the third category, the system appears to be booting normally so the suspicion is the path of the video signal from the video controller to the display. The second category has the most possible causes and is the most difficult to troubleshoot. Here is the basic "dead" PC troubleshooting hierarchy:
EXTERNAL SECTION
1. Observation.
A. Front panel LED's?
i. Yes: it is getting power
ii. No: possibly not receiving power
B. Front panel LED's of the monitor?
i. Yes: it is getting power
ii. No: it is definitely not getting power: Fix this - DONE?
C. Sounds (fans, drives)?
i. Yes: it is getting power
ii. No: possibly not getting power
2. Check the power supply fan.
A. Yes: it is getting power
B. No: Possibly...
i. not getting power: Check this - DONE?
ii. power supply fan has failed: Replace power supply - DONE?
3. Check Power Cable to System and Monitor
A. Plugged into system/monitor and outlet?
i. Yes: go to next check
ii. No: Correct this - DONE?
B. Plugged into a powerline appliance?
i. No: go to next check
ii. Yes: plug PC/display straight to wall outlet - DONE?
C. Wall Outlets working and wired correctly?
i. Yes: go to next check
ii. No: Correct this - DONE?
4. Check Video Cable: Connected securely to video controller output
and the display?
A. Yes: go to next check
B. No: Correct this - DONE?
5. Monitor functioning?
A. Yes: go to next check
B. No: Replace - DONE?
INTERNAL SECTION
6. Processor fan(s) functioning?
A. Yes: go to next check
B. No: replace fan (possibly CPU and motherboard as well!) - DONE?
7. Internal case fan(s) functioning?
A. Yes: go to next check
B. No: correct this, but heat damage to other systems...NOT DONE
8. General inspection of interior
A. Poor cooling (absence of additional case fans)?
i. No: go to next check
ii. Yes: Correct this, but heat damage to other systems...NOT DONE
B. Heavy dirt/dust?
i. No: go to next check
ii. Yes: Correct this - DONE?
C. Chip creep (socketed DIP chips raised in the sockets)?
i. No: go to next check
ii. Yes: Press them back down firmly - DONE?
D. Loose, broken, missing, or backwards cables, cards, connectors, screws, etc.
i. No: go to next check
ii. Yes: Correct this - DONE?
8. Strip down test - Leave keyboard, video card, RAM. Remove all other external and
internal periplerals including data cable attachments to motherboard. Turn on...
A. Displays POST screens: replace all other parts one-by-one until the problem part is
found - DONE?
B. Still "dead": Leave it stripped down and continue to next check
9. Video controller functioning (replace with a KGC - Known Good Component)?
A. Yes: go to next check
B. No: Replace - DONE?
10. Memory functioning (replace with KGC)?
A. Yes: go to next check
B. No: Replace - DONE?
11. Power supply functioning (test with meter, or better to replace with KGC)?
A. Yes: go to next check
B. No: Replace - DONE?
12. Motherboard and CPU functioning (difficult to test, try POST CARD)?
A. POST card identifies low level POST error: Replace motherboard/CPU - DONE
B. POST card does not initialize (stays at 00): either bad BIOS EEPROM, CPU,
motherboard. Replace in that order - DONE