POST-CARD

  • Thread starter Thread starter Armand
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A

Armand

I would like to bring up a problem previously posted here on the
continuous two-tone beep of a p3b-f board. Since then I got a "Computer
Main Board defect Post Card" I inserted it first in a PCI and later in
the ISA slot on my p3b-f motherboard, hoping to get a better clue on the
cause of the continuous siren like beep and no boot or signal indication
on the display. With only the Power supply, CPU, Memory and graphic
board connected to the motherboard. I obtained the following
indication: With the post-card inserted in the CPI slot, the error was
00 and LED lights for CLK, OSC, RST, 12v, 12v, -5v, 5v, but none for
BIOS. However when inserted in the ISA slot the LED for BIOS also lit-up
and the error signal code was FF instead of 00. According to the table
for Award BIOS in the POST instruction manual it means: Int 19 Boot
Attempt. I would greatly appreciate if anyone could enlighten me on
this. Is this motherboard only good for parts now as was previously
predicted? Or could it be fixed without major parts replacement?
Thank you,
Armand
 
Armand said:
I would like to bring up a problem previously posted here on the
continuous two-tone beep of a p3b-f board. Since then I got a "Computer
Main Board defect Post Card" I inserted it first in a PCI and later in
the ISA slot on my p3b-f motherboard, hoping to get a better clue on the
cause of the continuous siren like beep and no boot or signal indication
on the display. With only the Power supply, CPU, Memory and graphic
board connected to the motherboard. I obtained the following
indication: With the post-card inserted in the CPI slot, the error was
00 and LED lights for CLK, OSC, RST, 12v, 12v, -5v, 5v, but none for
BIOS. However when inserted in the ISA slot the LED for BIOS also lit-up
and the error signal code was FF instead of 00. According to the table
for Award BIOS in the POST instruction manual it means: Int 19 Boot
Attempt. I would greatly appreciate if anyone could enlighten me on
this. Is this motherboard only good for parts now as was previously
predicted? Or could it be fixed without major parts replacement?
Thank you,
Armand
Click to expand...

Your post card is essentially telling you that the voltages and clocks
it checks are good, but there is no POST activity. Hex codes FF and 00
are the two possible power on default states for the post card, prior to
it reading any data on port 80. You could probably get it to display
both default codes in either the PCI or ISA slot with enough power
on/off cycles. Which one you get is not significant. I don't know why
the BIOS led would be lit in one slot but not the other, or if that's
significant - a question for the post card vendor perhaps.

I assume you have done the basics already - i.e. careful inspection for
physical damage (including foreign objects in the slots or i/o
connectors), check that no 0-ohm fusible resistors are open, test the
battery, and try a known-good BIOS chip.

Does your post card have a 3.3v LED? If not you'll need to measure it
with a DMM. A vacant memory slot is the easiest to measure, you should
have 3.3v on the pin closest to the edge of the board on both sides of
the slot.

Other significant voltages not shown on the post card are Vcore (CPU
core) and Vtt (address/data signal reference). Vcore should match the
specified voltage for the CPU you are using, and is easiest to measure
at pin B73 on the Slot 1 connector - first pin to the left of the key,
on the back of the slot when the board is oriented with the i/o
connectors facing away from you. Vtt is easiest at pin A1, leftmost pin
on the front of the slot (same orientation). You need a CPU installed to
measure these voltages. I use short pieces of wire-wrap wire, strip a
bit of insulation off each end, and drop them into the holes in the top
of the slot 1 connector. When the CPU is inserted, the fingers are
pushed back in contact with the wires so measurements are easy.

If all of the above checks out as it should be, chances are the chipset
is damaged and the board is only good for parts - but if you find one or
more missing voltages it can probably be fixed. Don't give up just yet :-)
 
more but I shall try all of them. The resistance across the square
shaped F1 and F2 resistors was 0.2 Ohms dicounting the meter lead
resistance, but I don't suppose that is significant.
In case anybody is interested, this comming Saturday is the monthly TRW
computer swapmeet where last month among other things I picked up a
couple of slot1 cheap used defective? ($2 a piece) motherboards with
Award bios chips on them. This time I hope to find some better ones.
Does the Asus P2 series mother-boards have any advantages over the P3
series?
Thanks again,
Armand
 
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