CMOS Settings Changed by WinXP

Hi,

I have an old IBM Thinkpad T23 laptop computer. Recently, I have
trouble with the display, black, when I first power up the laptop. After
WinXP boots up, I hold down the Fn key and press F7 (int/ext display)
key to get the display turned on. I often have to do this more than once.

Note: I recently replaced the CMOS battery. I changed the BIOS
(press F1 at power up) setting for "boot display" from "both" to "LCD".

I SAVED the change, but the next time I boot up the T23, I have
the same issue. I reboot the T23 and press F1. BIOS settings, the
boot display is back to "both".

Does anyone know why WinXP changes the BIOS setting?

Thank You in advance, John

wrote:
Hi,

I have an old IBM Thinkpad T23 laptop computer. Recently, I have
trouble with the display, black, when I first power up the laptop. After
WinXP boots up, I hold down the Fn key and press F7 (int/ext display)
key to get the display turned on. I often have to do this more than once.

Note: I recently replaced the CMOS battery. I changed the BIOS
(press F1 at power up) setting for "boot display" from "both" to "LCD".

I SAVED the change, but the next time I boot up the T23, I have
the same issue. I reboot the T23 and press F1. BIOS settings, the
boot display is back to "both".

Does anyone know why WinXP changes the BIOS setting?

Thank You in advance, John


Are you sure that the settings are being saved? Go into CMOS and see if
the date and time are correct. Also, there is a jumper near the battery
that is used to clear CMOS. Could it have been changed during the
battery replacement?

wrote:
Hi,

I have an old IBM Thinkpad T23 laptop computer. Recently, I have
trouble with the display, black, when I first power up the laptop. After
WinXP boots up, I hold down the Fn key and press F7 (int/ext display)
key to get the display turned on. I often have to do this more than once.

Note: I recently replaced the CMOS battery. I changed the BIOS
(press F1 at power up) setting for "boot display" from "both" to "LCD".

I SAVED the change, but the next time I boot up the T23, I have
the same issue. I reboot the T23 and press F1. BIOS settings, the
boot display is back to "both".

Does anyone know why WinXP changes the BIOS setting?

Thank You in advance, John

My guess is, the T23 doesn't have a working main battery pack
installed in it. When you shut down Windows at the end of the day,
you likely unplug the adapter that is powering the T23 all
the time. This causes the RTC to run off the CR2032 coin cell
until the next morning.

For at least the BIOS setting, the CMOS RAM used for the setting
is battery-backed. If the CR2032 is flat, the CMOS settings
won't be maintained and the next morning when you plug in
the main adapter (as a surrogate for the missing battery pack),
the tiny CMOS power cell has not done its job, and so your
correction to the BIOS yesterday is being lost.

You'll need to find a manual or a takeapart, to identify where
the tethered coin cell is located. It has a tiny two-pin connector
on the end. There should be a pin header where it plugs in. The
CMOS cell likely has the wires on the battery end "cold welded"
to the metal surface. Then, they put that plastic pouch around it,
so that the conductors don't touch anything when the CMOS battery
is inside the laptop.

https://www.amazon.ca/DBTLAP-Compati.../dp/B07QTGNF4S

The battery is 3.0V or so when new. The Southbridge CMOS well minimum
voltage is 2.0V. A series diode with a forward drop of 0.3V prevents
current from flowing into that battery. So the minimum measured value
at the (+) terminal on the CMOS battery would be 2.3V or so. The CR2032
lasts for around 3 years, if no main battery pack is present to hold
up the load. The main battery pack would be contributing to the
electrical circuit if it was present. When the main battery pack
is missing, you use the laptop 8 hours a day, and 16 hours of the
day the CR2032 powers the RTC/CMOS, then the coin cell lasts
for about 3 years.

There are actually two kinds of coin cells. There are also rechargable
coin cells, similar in shape to the non-rechargable CR2032. You have
to be careful to replace "like-with-like". A CR2032 should definitely
not be used in place of the rechargable coin cell type, as the CR2032
is not rated for charging and it will swell up if charged.

https://en.wikipedia.org/wiki/Button_cell

"Rechargeable batteries typically have the same dimension-based numeric
code with different letters; thus CR2032 is a disposable battery while
ML2032, VL2032 and LIR2032 are rechargeables that fit in the same holder
if not fitted with solder tags. It is mechanically possible, though
hazardous, to fit a disposable battery in a holder intended for a
rechargeable; holders are fitted in parts of equipment only accessible
by service personnel in such cases."

You would replace the CR2032 with another CR2032.

*******

That doesn't say anything about how things work in Windows XP.

It's a guess at symptoms in your BIOS-level description. And
it's my guess the CR2032 has conked out, and with no main
battery pack to assist, it's the guilty party. The BIOS level
settings are now getting lost due to a lack of powering
(dead CR2032, no main battery pack).

Paul

In message , Paul
writes:
wrote:
Hi,
I have an old IBM Thinkpad T23 laptop computer. Recently, I
have
trouble with the display, black, when I first power up the laptop. After
WinXP boots up, I hold down the Fn key and press F7 (int/ext display)
key to get the display turned on. I often have to do this more than once.
Note: I recently replaced the CMOS battery. I changed the
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^
[]
is battery-backed. If the CR2032 is flat, the CMOS settings
[]
electrical circuit if it was present. When the main battery pack
is missing, you use the laptop 8 hours a day, and 16 hours of the
day the CR2032 powers the RTC/CMOS, then the coin cell lasts
for about 3 years.
[]
It's a guess at symptoms in your BIOS-level description. And
it's my guess the CR2032 has conked out, and with no main
[]
You're probably right. Maybe also bit of something got into the VGA
socket so it thinks it has an external monitor present (though I'd hope
it'd remember your choice so Paul's suggestion of the "recently
replaced" cell having failed is worth considering).
--
J. P. Gilliver. UMRA: 1960/1985 MB++G()AL-IS-Ch++(p)Ar@T+H+Sh0!:`)DNAf

The losses on both sides at Borodino [1812], 70 miles from Moscow, are the
equivalent of a jumbo jet crashing into an area of six square miles every five
minutes for the whole ten hours of the battle, killing or wounding everyone on
board. - Andrew Roberts on Napoleon, RT 2015/6/13-19

I have an old IBM Thinkpad T23 laptop computer. Recently, I have
trouble with the display, black, when I first power up the laptop. After
WinXP boots up, I hold down the Fn key and press F7 (int/ext display)
key to get the display turned on. I often have to do this more than once.

Note: I recently replaced the CMOS battery. I changed the BIOS
(press F1 at power up) setting for "boot display" from "both" to "LCD".

I SAVED the change, but the next time I boot up the T23, I have
the same issue. I reboot the T23 and press F1. BIOS settings, the
boot display is back to "both".

Does anyone know why WinXP changes the BIOS setting?

Thank You in advance, John

My guess is, the T23 doesn't have a working main battery pack
installed in it. When you shut down Windows at the end of the day,
you likely unplug the adapter that is powering the T23 all
the time. This causes the RTC to run off the CR2032 coin cell
until the next morning.

FYI:

You are correct, main battery pack defective, and removed. Note: I
replaced (with 2 AA batteries) the coin battery. This problem started a FEW
MONTHS LATER. It did NOT start right after I replaced the CMOS battery.

Also note: in the battery compartment, I used two NEW AA alkaline
batteries, and this laptop does NOT use a rechargeable CMOS battery.

The original CMOS battery is located in the same area as the main battery.

John

wrote:
I have an old IBM Thinkpad T23 laptop computer. Recently, I have
trouble with the display, black, when I first power up the laptop. After
WinXP boots up, I hold down the Fn key and press F7 (int/ext display)
key to get the display turned on. I often have to do this more than once.

Note: I recently replaced the CMOS battery. I changed the BIOS
(press F1 at power up) setting for "boot display" from "both" to "LCD".

I SAVED the change, but the next time I boot up the T23, I have
the same issue. I reboot the T23 and press F1. BIOS settings, the
boot display is back to "both".

Does anyone know why WinXP changes the BIOS setting?

Thank You in advance, John
My guess is, the T23 doesn't have a working main battery pack
installed in it. When you shut down Windows at the end of the day,
you likely unplug the adapter that is powering the T23 all
the time. This causes the RTC to run off the CR2032 coin cell
until the next morning.

FYI:

You are correct, main battery pack defective, and removed. Note: I
replaced (with 2 AA batteries) the coin battery. This problem started a FEW
MONTHS LATER. It did NOT start right after I replaced the CMOS battery.

Also note: in the battery compartment, I used two NEW AA alkaline
batteries, and this laptop does NOT use a rechargeable CMOS battery.

The original CMOS battery is located in the same area as the main battery.

John


Can you change the BIOS setting, then once the setting is saved,
use the power button to turn off the unit, then wait a bit
(with power adapter unplugged too), power on and verify the
BIOS setting is kept ?

In other words, keep the unit at "BIOS level" while testing
for the BIOS ability to keep the saved settings.

If your two AA cells are able to maintain 3V, the BIOS should
really be able to hold the settings. The AA cells should last
a long time, compared to a CR2032.

The CMOS cell is separated from the rest of the circuit
electrically with one leg of a dual diode. This means,
if the CMOS voltage is less than the shared node voltage,
no current flows from the CMOS cell. This has the added
advantage that if the polarity of the cell is reversed,
no damage should happen to the Southbridge. (The battery
socket typically prevents battery reversal mechanically, but
in the belt and suspenders sense, it also helps to electrically
protect the circuit too, just in case.)

While the hardware monitor on the SuperI/O has a "VBAT" input,
it's not clear what they're doing with that. I don't
think I've ever seen a verified "VBAT voltage measurement"
in any utility (that's why we use a multimeter to check it).

If the hardware monitor is measuring the VBAT voltage,
it's doing it pretty quietly. The ORed output from the
dual diode is supposed to be the real power source, not
looking at raw VBAT as such.

So while there is a raw VBAT pin on the hardware monitor,
it's not clear whether it can be blown out by CMOS battery
reversal. I've looked at a few SuperI/O datasheets, and
that portion of the design is *never* documented. It's
like some kind of mystery meat. This is why I'm unable
to determine how a flat battery, prevents some PCs
from starting - it's a "no documentation" problem.
None of the PCs in the house here, are stopped by
a flat or missing CR2032, so none of mine are
sensitive to VBAT.

I would try some BIOS level testing, and verify that
my battery solution, really was holding things up properly.
Other than battery reversal, I can't think of a lot
of excuses for it not to work.

Paul

I have an old IBM Thinkpad T23 laptop computer. Recently, I have
trouble with the display, black, when I first power up the laptop. After
WinXP boots up, I hold down the Fn key and press F7 (int/ext display)
key to get the display turned on. I often have to do this more than once.

Note: I recently replaced the CMOS battery. I changed the BIOS
(press F1 at power up) setting for "boot display" from "both" to "LCD".

I SAVED the change, but the next time I boot up the T23, I have
the same issue. I reboot the T23 and press F1. BIOS settings, the
boot display is back to "both".

UPDATE:

The CMOS setting had NOTHING to do with the display issue.

The problem is that switch (turns off back light) when you close the
"lid" while the laptop is "running". Note: I NEVER close the "lid" until
after I shut down the laptop.

John

On 03/04/2020 12:29, wrote:
I have an old IBM Thinkpad T23 laptop computer. Recently, I have
trouble with the display, black, when I first power up the laptop. After
WinXP boots up, I hold down the Fn key and press F7 (int/ext display)
key to get the display turned on. I often have to do this more than once.

Note: I recently replaced the CMOS battery. I changed the BIOS
(press F1 at power up) setting for "boot display" from "both" to "LCD".

I SAVED the change, but the next time I boot up the T23, I have
the same issue. I reboot the T23 and press F1. BIOS settings, the
boot display is back to "both".

UPDATE:

The CMOS setting had NOTHING to do with the display issue.

The problem is that switch (turns off back light) when you close the
"lid" while the laptop is "running". Note: I NEVER close the "lid" until
after I shut down the laptop.

John





Did you not have one day training on how to use a laptop?Â*Â* Everybody of
a certain age should take a one day course to acclimatise on any new
machine.

--
With over 1.2 billion devices now running Windows 10, customer
satisfaction is higher than any previous version of windows.

I have an old IBM Thinkpad T23 laptop computer. Recently, I have
trouble with the display, black, when I first power up the laptop. After
WinXP boots up, I hold down the Fn key and press F7 (int/ext display)
key to get the display turned on. I often have to do this more than once.

Note: I recently replaced the CMOS battery. I changed the BIOS
(press F1 at power up) setting for "boot display" from "both" to "LCD".

I SAVED the change, but the next time I boot up the T23, I have
the same issue. I reboot the T23 and press F1. BIOS settings, the
boot display is back to "both".

UPDATE:

The CMOS setting had NOTHING to do with the display issue.

The problem is that switch (turns off back light) when you close the
"lid" while the laptop is "running". Note: I NEVER close the "lid" until
after I shut down the laptop.

ANOTHER UPDATE:

At first, I thought that switch was the problem. I removed the button
type switch (normally open with "lid" up) thinking it was "leaky" (I have
seen this situation in some TVs I use to service).

The problem went away, but not for long.

Solution: I am now using an external monitor with this laptop.

John

wrote:

wrote:

wrote:

I have an old IBM Thinkpad T23 laptop computer. Recently, I have
trouble with the display, black, when I first power up the laptop.
After WinXP boots up, I hold down the Fn key and press F7 (int/ext
display) key to get the display turned on. I often have to do this
more than once.

Note: I recently replaced the CMOS battery. I changed the BIOS
(press F1 at power up) setting for "boot display" from "both" to
"LCD".

I SAVED the change, but the next time I boot up the T23, I have
the same issue. I reboot the T23 and press F1. BIOS settings, the
boot display is back to "both".

UPDATE:

The CMOS setting had NOTHING to do with the display issue.

The problem is that switch (turns off back light) when you close the
"lid" while the laptop is "running". Note: I NEVER close the "lid"
until after I shut down the laptop.

ANOTHER UPDATE:

At first, I thought that switch was the problem. I removed the button
type switch (normally open with "lid" up) thinking it was "leaky" (I
have seen this situation in some TVs I use to service).

The problem went away, but not for long.

Solution: I am now using an external monitor with this laptop.

When the screen comes up black, is it still displaying the screen's
display? With it black, you would be hard pressed to see if there was a
display of the OS desktop. Put a flashlight against the screen to see
if you can see the desktop or other output that would normally display
on the screen. While a flashlight at the front may only let you see a
very faint display on the screen, the light reflected through the
untwisted pixels hitting the diffuser and spreading to other pixels can
illuminate some from behind. Don't use a penlight or some cheapie
flashlight. Use a very bright one, press flat against the screen, and
look around the flashlight to see if you can see a faint display.

LCDs require a backlamp, or two. They twist to turn on/off the light
getting through. Behind the LCD screen is a difuser panel. That
spreads out the light from the backlamps (usually 2 on the sides). LEDs
panels are still LCD panels but use LEDs behind the LCD panel for
illumination. If the backlamps don't light up, you can't see the
display. With or without backlamps, the LCD panel could still be
working.

The problem could be with the backlamps, especially if the old CCFLs
(Cold Cathode Fluorescent Lamps) since those eventually fatigued and
die. The problem could be with the power inverter used to energize the
CCFLs. As the CCFLs wear out, they require more current which strains
the inverter. If you replace the CCFLs, you should also replace the
power inverter; else, you might end up having to dismantle and
reassemble the screen more than once. Some places just sell the CCFLs
and you have to separately buy the inverter. Some provide kits that
include the CCFLs, inverter, and seals and butyl tape since reusing the
old ones often means they won't seal or stick anymore. You can even get
brighter CCFLs than the old ones, but brighter can mean a more washed
out appearance of the display, and you can sometimes select a different
color temperature for the bulbs.

There are lots of Youtube videos showing how to dismantle a laptop,
replace the CCFLs, and reassemble the laptop. I don't recommend doing
this for a critical or sole computer. Despite having the mechanical
skills to dismantle, solder, and reassemble, you could make a mistake
and have to start over and perhaps buy another kit. It's been awhile,
but last time I looked at repairing my desktop's monitor, a kit cost
around $150 to $180. That was for a very high quality kit and with a
3-year warranty, parts from known and listed sources, CCFLs, inverter,
seals, and butyl tape, proper solder, heat-shrink tubing, and lots of
specs on the components and even instructions. As I recall, the tube
set cost $75, inverter was close to $45, and the miscellany was $20 or
more. All you had to provide was sufficient expertise to do the job.
You can buy cheap quality tube+inverter cheap kits for $20, but pricing
depends on your brand and model, and you have no assurance of the
quality or durability of the parts. They're selling on price, not
quality or reliability. However, the cost back then for a CCFL job was
close enough (a bit more than half) of the cost for a new monitor, so I
just went with buying a new monitor. I could spend all that money and
effort on replacing the backlamps, but end up with a botched job, and
have to buy another kit or redo the job hoping to get it right the next
time.

Can't simply replace the whole screen laptops. Well, actually you can.
There are sellers of laptop parts, like laptops that went bad, but other
parts of them are reusable, like the motherboard went bad but the
monitor still works. Usually those are as-is purchases as they are
selling a known defective product and the buyer hopes they can salvage
working parts.

Since you are using an external monitor, portability of that laptop is
not a critical or necessary use of that laptop. That's probably the
easiest solution. For a non-portable laptop (never leaves the desk), I
never bother using its screen, keyboard, or touchpad. Instead I used a
USB attached keyboard and mouse and an external monitor to have far
superior HIDs (Human Interface Devices: mouse and keyboard) and video.
Even for a laptop that I got from work to tote between work and home, I
used a docking station to facilitate using external HIDs instead of
having to wear the connectors on the laptop with repeated reconnections.

From your description, sounds like the LCD panel might still be working
even when black (use a flashlight to see if there is a display), but the
backlamps, inverter to power them, or both became defective. With
laptops, notebook, netbooks, tablets, and other small-format computers,
you have to choose to replace the backlamps and inverter, if possible,
whether to do the job yourself (hoping you get the proper kit and you
don't botch the job or damage the computer) or pay for someone else to
do it, use an external monitor, if possible, but forego portability, or
to replace the computer.

The Thinkpad T23 was introduced back in 2002. Pretty old. It was the
first Thinkpad that could render 3D graphics by switching from a
NeoMagic graphics card to an S3 Savage. Might still be passable for how
you use it. However, if you want portability (i.e., not stuck in one
location attached to a desktop monitor), time to start saving for a new
portable device. Or, you could get a portable monitor to lug around
with the defective laptop. Something else to stuff in the laptop bag.

SNIP
From your description, sounds like the LCD panel might still be working
even when black (use a flashlight to see if there is a display), but the
backlamps, inverter to power them, or both became defective. With
laptops, notebook, netbooks, tablets, and other small-format computers,
you have to choose to replace the backlamps and inverter, if possible,
whether to do the job yourself (hoping you get the proper kit and you
don't botch the job or damage the computer) or pay for someone else to
do it, use an external monitor, if possible, but forego portability, or
to replace the computer.

REGARDING THE BACKLIGHT INVERTER:

I forgot to mention that I swapped the inverter for the backlight using
one from another T23 laptop that has a bootup issue, but that did NOT
fix the problem.

John

wrote:

SNIP
From your description, sounds like the LCD panel might still be
working even when black (use a flashlight to see if there is a
display), but the backlamps, inverter to power them, or both became
defective. With laptops, notebook, netbooks, tablets, and other
small-format computers, you have to choose to replace the backlamps
and inverter, if possible, whether to do the job yourself (hoping
you get the proper kit and you don't botch the job or damage the
computer) or pay for someone else to do it, use an external monitor,
if possible, but forego portability, or to replace the computer.

REGARDING THE BACKLIGHT INVERTER:

I forgot to mention that I swapped the inverter for the backlight
using one from another T23 laptop that has a bootup issue, but that
did NOT fix the problem.

But did you try the flashlight trick when the screen was black?