Recently, my friend gave me a dead P3BF.
He told me the board initially refuses to boot and beeps all the time.
Then it refuse to boot completely.
I tested his board and it's dead, no beep and the fan is not moving.
The board has no visual damage.
I know P3bf is obsolete now, but I have the same board with the same
revision.
i just want to repair it for fun and learn something from it.
Question:
Is it possible that I can repair it by comparing the values from a
working board?
Which part should i look at first?
I plan to add a board repair page to my P2B Modification site, but never
seem to get to it :-(
I've pasted my notes so far below. The P3B-F is very similar to the P2B
series, so it's all equally applicable. Hope it helps.
Comments and suggestions welcomed.
P2B
http://tipperlinne.com/p2bmod
I have attempted repair of *many* dead P2B-S/DS/LS boards, but the
success rate is not good - about 30%. This is because the most common
failure mode is a dead BX chipset - a BGA device which cannot be
replaced without very expensive equipment. I suspect the BXs get killed
by people who don't take ESD precautions, or change PCI cards while ATX
standby power is applied to the board.
First inspect the board carefully for physical damage, bulging or
leaking capacitors (rare on P2Bs, but it does happen), or burned FETS.
Look for things like shorted header or i/o connections, foreign objects
in the slots etc. Check all 0 ohm resistors (aka fuses) for open
circuit, and all zener diodes for short circuit with a DMM.
Replace the BIOS chip with a known good one, check the battery voltage
with a DMM - replace if 2.8v or lower - then jumper the FSB to 66Mhz and
power up with a known good PSU and CPU (leave the second slot empty on
dual boards). No other components should be connected at this stage.
If the CPU fan spins, voltages generated onboard are probably good. If
it beeps long and loud, even better - try adding memory and video,
you've almost certainly fixed it
If the CPU fan spins but there are
no beeps, chances are the BX chipset is dead, but you may as well
continue diagnosis.
If the CPU fan 'twitches' at power up but doesn't spin, there's a
problem with the onboard VRM. Check all voltages generated onboard with
a DMM - Vcore (depends on the CPU you use for testing), Vio (3.2-3.5v),
Vtt (1.5V) and Vclk (2.5v). If any are missing, you'll need the
datasheet for the voltage regulator chip and an oscilloscope for further
diagnosis of the VRM circuitry.
If all voltages are present, check FSB and PCI clocks with an
oscilloscope. PLL datasheet required for further diagnosis if clocks are
missing.
If voltages and clocks are present, try pressing firmly on all the
surface mount chips one at a time, especially at the corners of chips
with pins on all 4 sides. Occasionally you'll find one that wasn't fully
soldered and eventually lost connection (again, rare on P2Bs but...) You
should get a beep if that's the problem.
If there are still no signs of life, chances of a bad BX chipset are now
even higher and a POST diagnostic card is required to proceed. If
there's no activity on the POST card at power up, the board goes in the
parts bin because it's not repairable but has known good voltage
regulator and clock components - which will come in handy for repairing
other boards or updating older revision boards. Otherwise, the numbers
on the POST card tell you where to look next.
