Bad CMOS?

I have two Dell Inspiron 3800 notebooks and am having the same problem
on both of them. When I press the "on" button, the LED's for the
on/off, caps lock and scroll lock all light up for about 4 seconds,
then goes off. The machines never even show the BIOS info screen.
These machines have been sitting around for a while unplugged, so I
suspect that there is a dead CMOS battery.

My questions are:

1) Does my guess of the CMOS battery being dead sound correct?
2) Is this something someone handy with a soldering iron could do
themselves?
3) Where can I get a CMOS battery for this model?

Thanks!

<> wrote in message
news: oups.com
> I have two Dell Inspiron 3800 notebooks and am having the same problem
> on both of them. When I press the "on" button, the LED's for the
> on/off, caps lock and scroll lock all light up for about 4 seconds,
> then goes off. The machines never even show the BIOS info screen.
> These machines have been sitting around for a while unplugged, so I
> suspect that there is a dead CMOS battery.
>
> My questions are:
>
> 1) Does my guess of the CMOS battery being dead sound correct?
> 2) Is this something someone handy with a soldering iron could do
> themselves?
> 3) Where can I get a CMOS battery for this model?

Yes it sounds like the CMOS battery is dead to me. And yes you should be
able to replace it. There are lots of battery websites that you should
find a replacement.

--
Bill

wrote:
> I have two Dell Inspiron 3800 notebooks and am having the same problem
> on both of them. When I press the "on" button, the LED's for the
> on/off, caps lock and scroll lock all light up for about 4 seconds,
> then goes off. The machines never even show the BIOS info screen.
> These machines have been sitting around for a while unplugged, so I
> suspect that there is a dead CMOS battery.
>
> My questions are:
>
> 1) Does my guess of the CMOS battery being dead sound correct?
> 2) Is this something someone handy with a soldering iron could do
> themselves?
> 3) Where can I get a CMOS battery for this model?
>
> Thanks!

1. That's not the classic CMOS failure I'm familiar with, but IF the
systems were highly customized, then I guess it certainly could be a CMOS
battery problem. Pretty unusual for two to go bad at the same time though.
2. The CMOS batteries are not charged, ever, by anything in the computer/s.
It's the same as the ones in your watch; they work for awhile, then they
quit.
3. CMOS batteries are changeable without a soldering iron and usually there
is a small compartment you access with a screwdriver in order to change the
batteries.
4. To get a battery, pull out the old one and take the numbers with you to
the store. Or check the documentation that came with the computers for the
numbers. And how to access them.

It sounds more like the computer's batteries are dead: Are you plugging
them into ac to check them out? The computer's batteries very likely need
to be rechaged.

Pop

The CMOS battery is a possible culprit, but nothing more. Almost all
laptops will work with a completely dead CMOS battery. But some models
won't. Don't know about your model.

Leave the laptops plugged in for 24 hours. Most laptops have
rechargeable CMOS batteries. On some models, the battery only charges
while the laptop is turned on (not simply plugged in, but actually
turned on). Of course, this would be a bad design in a machine that
won't turn on with a dead CMOS battery.


wrote:

> I have two Dell Inspiron 3800 notebooks and am having the same problem
> on both of them. When I press the "on" button, the LED's for the
> on/off, caps lock and scroll lock all light up for about 4 seconds,
> then goes off. The machines never even show the BIOS info screen.
> These machines have been sitting around for a while unplugged, so I
> suspect that there is a dead CMOS battery.
>
> My questions are:
>
> 1) Does my guess of the CMOS battery being dead sound correct?
> 2) Is this something someone handy with a soldering iron could do
> themselves?
> 3) Where can I get a CMOS battery for this model?
>
> Thanks!
>

Re: "The CMOS batteries are not charged, ever, by anything in the
computer/s. It's the same as the ones in your watch; they work for
awhile, then they quit."

That is categorically wrong. Some laptops do use one-time CMOS
batteries (as you describe above), but many (most, in my experience, but
my experience is mostly with Toshiba and some Dell) use rechargeable
CMOS batteries that are not considered to be user replaceable (although
they are not really that hard to replace). All Toshiba models that I
have worked on use rechargeable CMOS batteries.

"Pop`" <> wrote in message
news:uOq%g.4490$rx.2784@trnddc04
>
> 1. That's not the classic CMOS failure I'm familiar with, but IF the
> systems were highly customized, then I guess it certainly could be a
> CMOS battery problem. Pretty unusual for two to go bad at the same
> time though. 2. The CMOS batteries are not charged, ever, by anything
> in the
> computer/s. It's the same as the ones in your watch; they work for
> awhile, then they quit...

Most laptops use rechargeable Ni-Cad or Ni-MH batteries. Those that use
Lithium button cells are popular in desktops, but rare in laptops. And
how they charge is different. Like my Toshiba 2595XDVD laptops tickle
charge the CMOS battery, only when the backlight is on. If you have the
laptop on 24/7, but has the backlight always off, you will run down the
CMOS battery in about 5 to 6 months. The same thing whould happen if you
didn't plug it in all of that time.

--
Bill

"Barry Watzman" <> wrote in message
news:
> Leave the laptops plugged in for 24 hours. Most laptops have
> rechargeable CMOS batteries. On some models, the battery only charges
> while the laptop is turned on (not simply plugged in, but actually
> turned on). Of course, this would be a bad design in a machine that
> won't turn on with a dead CMOS battery.

My Toshiba 2595XDVD laptops only charge the CMOS battery whenever the
backlight is on, according to the manual. This model also sports a
backup RAM battery (yes a third battery). In both of mine, they are
dead. But what they do is to allow you to swap the main batteries in
standby mode (up to 30 minutes of RAM power). Which is a very good idea.
<grin>

--
Bill

wrote:
> I have two Dell Inspiron 3800 notebooks and am having the same problem
> on both of them. When I press the "on" button, the LED's for the
> on/off, caps lock and scroll lock all light up for about 4 seconds,
> then goes off. The machines never even show the BIOS info screen.
> These machines have been sitting around for a while unplugged, so I
> suspect that there is a dead CMOS battery.

I assume you tried turning it on without the main battery in.

> My questions are:
>
> 1) Does my guess of the CMOS battery being dead sound correct?

Unlikely. Remember, when the system is plugged in, or operating from the
regular battery, the RTC and CMOS are not being powered by the small
Lithium coin cell battery. Many systems use rechargeable "bridge"
batteries, and dispense with the non-rechargeable lithium coin cell. The
bridge batteries allow you to swap main batteries without turning the
system off.

> 2) Is this something someone handy with a soldering iron could do
> themselves?

It depends where the battery is located. I couldn't find any information
on this. On some notebooks, it's accessible via a panel on the bottom,
maybe even behind a disk drive or battery. On some it's under the
keyboard, because keyboard removal is usually very simple (keyboards are
added at final assembly because they vary by country, so they generally
are easy to remove without full disassembly.

> 3) Where can I get a CMOS battery for this model?

I don't think you can.

Look at
"http://www.mdsbattery.co.uk/departments/department002.asp?Brand=Dell&DepartmentName=Comput er+Clock%2Fcmos+batteries&DepartmentID=141"
where they don't list the 3800, but do sell the batteries for older and
newer Dell models.

> Thanks!
>

On other Toshiba models, the requirement is that the computer is on
(it's ok if the timeout has shut off the LCD screen as long as the
computer itself is still on). This varies by model and manufacturer,
some will charge with the computer off (but plugged into a live
charger). All that can be said is to consult the manual.


BillW50 wrote:

> "Barry Watzman" <> wrote in message
> news:
>
>> Leave the laptops plugged in for 24 hours. Most laptops have
>> rechargeable CMOS batteries. On some models, the battery only charges
>> while the laptop is turned on (not simply plugged in, but actually
>> turned on). Of course, this would be a bad design in a machine that
>> won't turn on with a dead CMOS battery.
>
>
> My Toshiba 2595XDVD laptops only charge the CMOS battery whenever the
> backlight is on, according to the manual. This model also sports a
> backup RAM battery (yes a third battery). In both of mine, they are
> dead. But what they do is to allow you to swap the main batteries in
> standby mode (up to 30 minutes of RAM power). Which is a very good idea.
> <grin>
>

Re: "any systems use rechargeable "bridge" batteries, and dispense with
the non-rechargeable lithium coin cell. The bridge batteries allow you
to swap main batteries without turning the system off."

What you call a "bridge battery" is unrelated to the CMOS battery -- two
separate batteries (neither being the "main" battery). Some Toshiba
models that I service has as many as three small internal batteries, in
addition to the main battery, but in Toshiba models two batteries (CMOS
and your "bridge battery") are very common. In all of the Toshiba
models that I have seen (most from 1995 to 2006), Toshiba uses
rechargeable NiMH batteries for the internal batteries. They are not
soldered in place, but rather plug-in, but they are not considered
user-replaceable, either, as some disassembly is required to access
them. Most often, they are located under the keyboard.

SMS wrote:

> wrote:
>
>> I have two Dell Inspiron 3800 notebooks and am having the same problem
>> on both of them. When I press the "on" button, the LED's for the
>> on/off, caps lock and scroll lock all light up for about 4 seconds,
>> then goes off. The machines never even show the BIOS info screen.
>> These machines have been sitting around for a while unplugged, so I
>> suspect that there is a dead CMOS battery.
>
>
> I assume you tried turning it on without the main battery in.
>
>> My questions are:
>>
>> 1) Does my guess of the CMOS battery being dead sound correct?
>
>
> Unlikely. Remember, when the system is plugged in, or operating from the
> regular battery, the RTC and CMOS are not being powered by the small
> Lithium coin cell battery. M
>
>> 2) Is this something someone handy with a soldering iron could do
>> themselves?
>
>
> It depends where the battery is located. I couldn't find any information
> on this. On some notebooks, it's accessible via a panel on the bottom,
> maybe even behind a disk drive or battery. On some it's under the
> keyboard, because keyboard removal is usually very simple (keyboards are
> added at final assembly because they vary by country, so they generally
> are easy to remove without full disassembly.
>
>> 3) Where can I get a CMOS battery for this model?
>
>
> I don't think you can.
>
> Look at
> "http://www.mdsbattery.co.uk/departments/department002.asp?Brand=Dell&DepartmentName=Comput er+Clock%2Fcmos+batteries&DepartmentID=141"
> where they don't list the 3800, but do sell the batteries for older and
> newer Dell models.
>
>> Thanks!
>>
>