David said:
Thanks for the ideas guys. Things have deteriorated rapidly since
yesterday. I can no longer get into safe mode, because the screen is
now garbled from startup, including the DOS pages. This got
progressively worse over the day until it is now useless. For the same
reason, I can't use a boot disk because I can't change the startup
order. Floppy startup disks don't work anyway, even though they are
first in line. The screen itself is fine, and runs normally on another
PC. I have cleared the CMOS and fitted a new battery to no avail.
Because the graphics are scrambled from the beginning, I assume it can't
be the video card, as this does not come on stream until after the DOS
pages. The startup sequence lights on the MSI motherboard show three
greens and one red, indicating fail at 'Testing real time clock'. It
implies that everything else is OK, but it isn't in fact. I have had all
greens several times, but the results are the same. The hard drive
activity light is on and steady all the time. All this seems to
suggest it is either the motherboard itself or the processor, which is
an AMD 1.13 GHz. I can't see it being memory. I am happy to buy a new
PC, but I would still like to get the old one working so I can transfer
files etc.
Does this seem a logical train of thought?
If you have 1.5GB of RAM, that means there are multiple sticks of RAM present.
You can move the sticks around, so if there is a defect in the RAM (like
below 640K), that area might not be bad in a second stick.
Stick_1 Stick_2 Stick_3
to
Stick_2 Stick_1 Stick_3
and so on. The memory addresses assigned to the sticks, should
follow the slot order, on a single channel three slot board.
(On a dual channel motherboard, you need to think "single channel mode"
to do this.)
As to your comment about graphics, when the computer first starts up,
and your BIOS is running things, the video device is run in some VESA
mode. That is what gives you a 640x480 screen. The BIOS queries the
device, to see what modes are supported. Normal video devices, whether
they're integrated graphics or a separate video card, follow that
convention. They all should support the mode the BIOS is looking for
(with some Matrox cards being an exception and mis-behaving).
Nvidia has had a string of chip failures, due to how the chips make
their electrical connections. That would be an example of a situation,
where you'd be curious about the brand of video, and the vintage, as
a means of identifying a higher probability of failure. Some people
have actually managed to "bake" the PCB assembly in their computer
that is affected and fix it. But that is a pretty extreme solution,
when you consider that the person baking their motherboard or video
card, has no idea what temperature they're applying. That's like
whacking a vacuum tube (CRT) TV on the side, to make it stop "flipping".
A motherboard video could also fail, due to the motherboard regulator
powering the video, having failed. And that would be classed as a
motherboard failure.
So I would start with the sticks, and see if things improve with
some simple swaps. After the one above, I'd try this one next.
Stick_1 Stick_2 Stick_3
to
Stick_1 Stick_3 Stick_2
If you only have two sticks, there are fewer test cases
If you can boot something like memtest86+, you can use that for
testing, but that can't test the memory reserved by the BIOS
(below about 1MB). Which is why the stick rotation is a useful
thing to try, in conjunction with running the test. Two
error free passes of this is enough testing, before trying
your next hardware configuration. Test 5 is where you may observe
your first failures - if you're in a hurry, you can advance to
Test 5.
http://www.memtest.org (for CD, USB key, floppy)
What MSI motherboard is this ? The name may be printed
in white letters, on the motherboard surface. In this example,
you can see "KM4M" (it is actually KM4M-L), and MS-6734 Ver.1
as identifying marks. You may need to zoom in to see those.
This is a VIA chipset Athlon board, with integrated graphics
under the heatsink.
http://www.msi.com/uploads/prod_eea119d9512d4e2abc561d8b006c2466.jpg
Paul
