internal battery ?

Clarifications

I believe it is just some super capacitor that provides power to the clock when the system is off. On a desktop system there IS a battery that usually needs to be replaced every 7-10 years.

If either device were to "go dead" then the worst that happens is your CMOS gets erased and your clock and date become wrong. They reset to January 1st, 1980.

Yes, I have a Toshiba that I have cleaned up for a family member that does have an internal rechargeable battery for the CMOS and real time clock.

Before you start hunting for the battery though, it sounds more like a power supply circuit problem to me.

The question to answer, is if you remove the regular battery and unplug the computer does it loose the real time clock after a few hours?

If the real time clock looses a lot of time, or even resets without any other power to the laptop, then yes, the internal battery needs to be replaced.

However, if it keeps time, then you have an internal power problem inside the laptop. Most likely is that one or more battery contacts are not making proper contact between the battery and the laptop.

As the charging circuits and power circuits are separate, it is possible to charge a battery but not be able to run off of a fully charged battery.

You will need to inspect both the battery and the contacts inside the battery compartment to make sure that none are bent, broken, corroded or missing.

Chas

Firstly yes the Satellite pro DOES have a battery on the motherboard, I know this because I have one in bits in my cupboard.
I can also tell you that you have to dismantle the entire machine to get to it.
However the problem you describe does not seem to be a battery issue and I would think it will be a sspecialist job to fix the charging circuit on the motherboard