Shon said:
ok, now when I turn on my PC nothing is showing on screen. all cables
are connected. possible issue with the integrated video on motherboard.
I bought another graphics card and still nothing. I've connected the
monitor to another pc, and it's not the monitor. any suggestion on how
to proceed??? thanks
Does your PC beep, when there are serious hardware errors ?
One of the tests I like to use, is a beep test. These are
some tests you can try.
1) Power down and unplug the computer (this prevents +5VSB from
being present, on the hardware sockets). Remove all the sticks
of RAM. This test should work with all PCs, because they hate
it when you remove the RAM.
The PC case speaker (or a piezoelectric speaker on the motherboard),
will beep an error code. (On some Dell boxes, they also have a
four LED display, which displays an error code.)
The purpose of this test, is to prove the BIOS code is getting
executed. To beep the speaker, at least on modern machines,
requires some BIOS code execution. The BIOS code, can run in processor
registers, at least until the RAM test is completed.
If you hear a beep code, coming from the internal speaker, that
tells you the processor is working, and it ran some of the BIOS
code from the BIOS chip. It proves a significant portion of the
PC is working.
If you don't hear a beep, with the RAM missing, then the processor
likely was not able to run the BIOS code. Sometimes, this can be
caused by a weak BIOS battery (3V CR2032 coin cell). The processor
power plug (2x2 ATX12V cable) may have been unplugged. (Check the
two power cables, and make sure they're completely seated.) The BIOS
could have been corrupted somehow. Or, check the capacitors (aluminum
cans with plastic sleeving) near the processor socket. If the
tops are bulging or brown stuff is dried on them, they could be
leaking. This can cause the Vcore supply to the processor, to
malfunction. No Vcore = no computing.
2) You can also try this test for video. But some motherboards
have built-in video, and if that is the case, the motherboard
may just decide to use the built-in. So while you can also try the beep
test, by removing the video card, this test only applies to motherboards
that don't have built-in video in the chipset. The RAM test in (1),
is more of a sure thing.
I take it, when the power comes on, the cooling fans are spinning ?
The cooling fans run from +12V, so that helps confirm there is some
+12V available. The hard drive also uses +12V, and if you place a
finger on the body of the hard drive, you may feel some vibration
from the spinning of the platters inside. The motor on the hard
drive (on a desktop), is powered from +12V.
As a last resort, you can remove the processor heatsink, and examine
the condition of the processor. In particular, if you had an
old Athlon or Athlon XP processor, those have a bare silicon die,
and sometimes the die is cracked or burned. But playing with
it, is also dangerous, since every time you reinstall the
heatsink, you run the risk of cracking chips off the edge
of the silicon die. Athlon processors may come with rubber
"bumps" or a shim in the processor area, and the purpose of
these added items, is to cushion the heatsink during installation,
such that the heatsink cannot rock and push on the delicate
edges of the Athlon processor.
For other processor types, there is less to worry about.
When reinstalling a heatsink, you need to use some thermal
interface material, to aid in heat conduction. If the
existing thermal interface material is scratched up or uneven,
then you can apply fresh material. This is one example. A
dab of material the size of a grain of rice, should be
enough.
http://www.newegg.com/Product/Product.aspx?Item=N82E16835100009
http://www.arcticsilver.com/ceramique_instructions.htm
Anyway, your first test should be the RAM beep test (1).
Post back what happens.
When the RAM is removed, it should be stored in an antistatic
bag. You want to be touching the chassis, while handling the RAM,
so you and your body are at the same electrostatic potential as
the rest of the hardware. Place the RAM inside the antistatic bag,
while touching the chassis.
An easier way to handle RAM, is with an antistatic wrist strap.
With one of these on your wrist, and the clip on the end clamped
to shiny metal on the PC chassis (even a screw on the I/O connectors
would do), this helps keep you at the same electrostatic potential
as the chassis. The strap should have a high ohm resistor inside it,
as the strap is intended to drain static discharges slowly. So an
ordinary piece of bare wire, wrapped around you, is not as safe
as an alternative to one of these straps. We used these straps all
the time, in the hardware lab. And we'd get rapped on the
knuckles, if caught without one. Hardware labs have strict
antistatic handling policies. (In some labs, you even need
antistatic shoes, and the floors are conductive and connected
to ground.)
http://www.radioshack.com/product/index.jsp?productId=2479151
HTH,
Paul
