Hardware Reference
In-Depth Information
came with an older BIOS version. All I had to do to solve the problem was to upgrade the BIOS, but
how was I to do that since the board wouldn't even run with the processor until after the BIOS had
been upgraded? I was in a classic chicken-before-the-egg situation. In the end I found a friend who
had an older processor, one that would work with the older BIOS in my motherboard. I borrowed the
chip and installed it just long enough to perform the BIOS upgrade; then I removed the borrowed chip
and reinstalled the new one I had originally purchased. The system then worked perfectly.
The system runs fine for a few minutes but then freezes or locks up.
This is the classic symptom of a system that is overheating. Most likely the CPU is overheating, but
other components such as the video card or motherboard chipset can also be overheating. If the
system is new or custom built, the design might be insufficient for proper cooling, and bigger
heatsinks, more fans, or other solutions might be required. If the system was working fine but now is
exhibiting this problem, check to see whether the problem started after any recent changes were made.
If so, then whatever change was made could be the cause of the problem. If no changes were made,
most likely something such as a cooling fan either has failed or is starting to fail.
Modern systems should have several fans—one inside the power supply, one on the CPU (or
positioned to blow on the CPU), and optionally others for the chassis. Verify that any and all fans are
properly installed and spinning. They should not be making grinding or growling noises, which
usually indicates bearing failure. Many newer systems have thermostatically controlled fans; in these
systems it is normal for the fan speeds to change with the temperature. Make sure that the chassis is
several inches from walls and that the fan ports are unobstructed. Try removing and reseating the
processor; then reinstall the CPU heatsink with new thermal interface material. Check the power
supply and verify that it is rated sufficiently to power the system (most should be 300 watts or more).
Use a digital multimeter to verify the voltage outputs of the power supply, which should be within 5%
of the rated voltage at each pin. Try replacing the power supply with a high-quality replacement or
known-good spare.
I am experiencing intermittent problems with the hard drive(s).
Typically, intermittent problems are found with the cable and the drive—it is far more rare that the
host adapter fails or exhibits problems. SATA drives use simple cables that connect directly from the
host adapter (usually on the motherboard) to the drive. Try replacing the cable with a known-good
spare. PATA drives use either 40-conductor or 80-conductor cables, with one 40-pin connector at
either end and optionally one in the middle. Drives supporting transfer rates higher than ATA-33
(33MBps or Ultra DMA Mode 2) must use 80-conductor cables. Check the cable to ensure that it is
not cut or damaged; then try unplugging and replugging it into the drive and motherboard. Try
replacing the cable with a new 80-conductor version.
If replacing the cable does not help, try replacing the drive with a spare, install an OS, and test it to
see whether the problem remains. If the problem remains even with a known-good drive and cable,
then the problem is most likely with the motherboard, which will probably need to be replaced.
If your system uses Serial ATA (SATA) hard disks, keep in mind that the cable and connector design
used by some motherboards and SATA hard disks does not include a locking mechanism. The cable
might have become disconnected from the motherboard or hard disk. SATA cables can also fail if
they are bent or cut. Replace damaged cables, and make sure the cable is connected to the drive and
motherboard or host adapter card.
The system won't boot up; it says
Missing operating system
on the screen.
