These models have actually three internal batteries to take care of. First off the main battery pack for mobile usage, assumingly the one you said in the beginning was dead. Then we have two additional ones inside. Both are NiMH or NiCd rechargeables. One is the 3,6V BIOS battery, the other bigger one is the 7.2V Resume battery, that fires at the RAM while the machine is in hibernation.

Now, two of these are optional, as you have probably already guessed. The main battery pack of course is not needed when using mains power. The resume battery (7.2V) is optional as well. I have remove all of these two batteries in all of my Satellite models.

The third one, the BIOS battery, is not optional, I say that though of course it is possible to use the computer without one, having to enter the BIOS data again after each time you unplug it from the mains. But there are also some Satellite models that refuse to boot if no CMOS battery is present.

That being said the symptom you are describing are - if I understood that correctly - that it starts up, shows video BIOS version, give off a beep and proceeds to show a blank screen with blinking cursor? In that case it might be hanging probing/initialising either the IDE device it wants to boot from or cannot initialise the keyboard controller. What is interesting is that it should throw out an error of sorts, actually more than one, as in KEYBOARD CONTROLLER FAILURE / CMOS BATTERY ERROR / IDE DEVICE ERROR.

The fact that it does not and just stalls, could mean that it hangs half ways through trying to initialise something. For example, this is a symptom you would also get when the keyboard ribbon cable is only half way in, as opposed to completely detached which would throw out an error. Due to this, this behaviour could mean a lot of things. I would try replacing the CMOS battery pack with a 3.6V barrel drum (even if you cant find a "flat pack" you can use a barrel drum shaped version and just use longer cables and since you have no main battery anymore you can easily fit it somewhere in that now empty battery compartment for example), disconnecting and reconnecting the keyboard cable, etc.

Sorry it took me so long to reply. But it finally booted after sitting for a few minutes! Now I am trying to source a replacement CMOS battery 😀 Thanks for all of your help!

Sorry to bump this old thread, but I'm trying to source a replacement RTC battery as well, with no luck so far. Has anyone found one?

Flatpacks of V40H cells were originally used for these. The Flatpack variants are hard to find these days, but you would be able to use a barrelpack instead. Considering the fact that you probably are not using a main battery anymore and even if - these Satellites all have enough places/niches in them to fit a barrel shape with longer cables instead. Try hunting down a V40H 3.6V of these , they are much smaller than depicted and I used a lot of them in various Satellites and usually always found a place for them inside the machine.

Here is an example of me using one of these instead of flatpacks....

If you are planning on not using it for a prolongue time / plan on putting it in storage, disconnect the rechargeable batteries first.