Re: Flash bios without CPU

dropzone@xxxxxxxxxxx wrote:


Oh and I forgot, I also tried removing the pcie video card and putting
an old pci video card. The pc speakers are also plugged and I hear no
beeps, and there is still no display... what the??

OK, so you've got the P5KC back from RMA ?

You can start very simply at first.

1) Connect the power supply main connector, to the motherboard.
2) Connect the front power switch, to the appropriate two pins
on the PANEL header.
3) Now, plug in the power supply. When you push the power button
on the front of the computer case, you should hear the power
supply come on, and the PSU fan should start to spin and keep
spinning. You should even be able to press the button a second
time, and switch it off again.

That is a motherboard with nothing plugged into it, and in that
configuration, it should be able to switch the power supply on and
off.

Page 37 here, will give you the pinout of the new Startech supply.
This document is suitable for the new 24 pin power supplies for
desktop use.

http://www.formfactors.org/developer/specs/ATX12V_PSDG_2_2_public_br2.pdf

If you still aren't getting anywhere, you can do a test on the power
supply. Now, some people I've had conversations with, don't really
feel comfortable doing this test without a load on the PSU. If you
have a couple of old hard drives, ones you don't care about, you
could connect them to a couple 1x4 Molex plugs on the power supply
to be tested. That will put a bit of load on the supply for testing.

To turn on an ATX supply, when it is not connected to a motherboard,
you connect the PS_ON# signal (green) to an adjacent COM (black)
wire. You can use a paper clip, to make a shorting plug, to insert
in the two adjacent holes. (Only a tiny current flows in the paper
clip, so it doesn't get hot, and won't shock you, as it is at a 5 volt
level.) For as long as the paper clip makes contact, the PSU fan
should spin, and the couple disk drives you connected as a load,
should spin up and make a bit of sound. (Since I have a homemade
load box, with power resistors to load the PSU, I can do this more
easily.)

So that would be a simple test that the PSU can be switched on.
If the PSU responds to the paper clip, and yet will not switch
on, when a motherboard and associated front power switch are
used, then it could be the motherboard which is at fault.

Also, if you think the front power switch is bad, you can swap
the reset and power switch cables, and just use the reset button
as if it was a power switch. Both buttons work the same way, so
are interchangeable for testing purposes.

If you are able to pass the "motherboard + PSU switch-on test",
then you're ready to add more components to the motherboard.
The CPU would be next, and also the computer case speaker would
be a good thing to add. The speaker is useless without the CPU,
which is why I didn't add it for the first test.

As you add components, listen to the beep codes on the speaker.
With the CPU, heatsink/fan installed, but no RAM, a good thing to
hear would be the "missing RAM" beep code. Adding RAM as the
next test, gives "missing video" beep code. Adding the video card
and monitor, means moving on from the speaker, and watching the
monitor screen, for any more error codes. The beep codes will help
you decide, whether the computer is proceeding down the correct
path in the "testing flow chart", if you can picture that
chart in your mind's eye.

I've built two computers, by following these tests (even though
I suspected the components were good). I actually build up the
whole computer, and boot it while it sits on the table top.
Because then I know everything is ready to go. Then I can
assemble the computer in a case, confident that it'll work.
To do that, you need a large, clear area to work, with no
little kids around :-)

HTH,
Paul
.

Quantcast