Power supply is a less likely reason for problem. Return to
the symptoms. It works fine when started while 'always on'
part was powered from AC mains (power switch on power strip
always on)(condition A). It works fine when computer is
running - turning peripherals and even parts inside the CPU on
and off - normal run mode (condition B). Problem only occurs
when power to 'always on' parts of computer is removed before
startup (condition C).
If power supply works just fine during conditions A & B.
Power supply is OK. Locate a problem only unique to condition
C.
If battery was going bad, then clock previously was quickly
losing time when computer was powered off. If battery got so
bad as to let CMOS loose important data, then BIOS would first
detect bad CMOS checksum error and announce problem during
power up. If clock has been maintaining time weeks previously
and CMOS Checksum error is not announced, then battery is not
likely to be reason for failure.
Furthermore, battery and CMOS are not related to condition C
- the problem condition.
All subsystems must receive a reset signal to put every
memory (register or state device) in a known condition. Reset
can be generated three ways - reset 1) from a master reset
signal, reset 2) by detecting a voltage turn on and maintain
create a reset long enough for power supply voltage to
stabilize, or reset 3) commanded by software.
Lets assume your keyboard is reason for a BIOS hang.
Keyboard has its own single chip computer (originally the
famous 8048 or 8051 series). Now that computer, during power
up must first be reset. How?
Computer master reset (reset 1) typically does not exist.
Therefore keyboard must reset either by detecting voltage turn
on (reset 2) or from a software command (reset 3). Reset 3
assumes computer is already running - can understand reset 3
message.
When you leave power strip in power on condition, then the
many 'always on' circuits inside that system remain powered.
This is condition A - powerup without failure. Typically
connected to that 'always on' power is keyboard. Once BIOS
starts executing, then BIOS (before booting XP) will issue a
software command (reset 3) to that keyboard computer.
Keyboard computer then acknowledges the message. BIOS moves
on to setup other parts of computer. No hangup.
Now lets assume you turned power strip off. The 'always on'
circuits are no longer powered. When you turn power strip on
- condition C, then keyboard must generate its own master
reset (reset 2). But what happens when that keyboard (reset
2) circuit is not quite right? Sometimes it resets correctly
- but not always. When keyboard's internal master reset does
not work, then BIOS hangs waiting for a response from
keyboard. This type of reset only occurs during Condition C -
power strip switch cycled.
This hardware defect is not observed when computer is always
connected to wall receptacle because keyboard always remains
powered - condition A powerup - component need not create its
own reset (reset 2).
Also some components create a reset 2 so slow that it works
for some power sources and not others. That is still a
defective reset 2 regardless of which power supply is used.
Reset 2 should be so long as to make power supply response
irrelevant - a design defect in the component.
One way to test keyboard computer's (reset 2) functions is
to remove and connect keyboard while Windows is working. If
reset 2 works, then keyboard will continue working normally.
This simulates a condition A power up limited only on
keyboard. It tests keyboard's own internal reset 2 circuit.
Again, above assumes BIOS was getting stuck waiting for
keyboard. Other components also can hang the BIOS. Some
BIOSes will time out - announce the failure using error
message on screen or via beep codes from speaker. For a
better answer, you must supply more information. But power
supply and CMOS, typically, would not be reason for this type
of failure. Power supply or CMOS would also have to create a
condition A power up failure.
To create a list of devices that can cause your problem,
identify which components are part of the 'always on'
circuit. 'Always on' may include network card, mouse, modem,
and another important motherboard circuit - the power supply
controller. Try a condition C powerup with each 'always on'
peripheral removed. By process of elimination, the offending
component can be identified.
Why understand conditions A-C? If you remove an NIC or
modem while computer is ready for condition A (computer
appears off but 'always on' circuits fully energized), then
that card or motherboard port can be damaged. Never work on
computer with power cord connected to wall or power strip.
Just because it looks off means nothing. Without a meter, you
don't know what is what.
The problem is quite simple to solve. The difficult part is
comprehending so much new information. Take it real slow if
don't appreciate how hardware works; for example did not even
know of those three types of resets nor the three types (A -
C) of power conditions. To understand little tests that would
locate this problem, one should reread this post at least
three times; each reading discovers more information. I do
same thing when doctor prescribes a drug. Its not hard.
Simply takes reading multiple times.
Will UPS solve any of this? Of course not. UPS connects
computer directly to wall receptacle when not in battery
backup mode. IOW UPS has same circuits connecting computer
directly to wall - just like as that protector strip (when UPS
is not in battery backup mode).
Smoking power strip: power strip must have a 15 amp circuit
breaker as also provided on $3 power strips. Unfortunately,
too many protectors power strips are so expensive, and still
don't have that important 15 amp circuit breaker. No circuit
breaker; then dispose of it as a threat to human life.
