|A dead or too weak Cmos battery, alone, will NOT cause the computer to not boot. |
However, a shorted one may cause problems.
Laptop no video (or video problems), and battery, AC adapter, power jack T shooting.
See response 1:
DO NOT plug in or unplug a monitor's video cable into / from a video port while the computer is running. Doing so can damage the monitor's circuits and/or the video adapter's circuits.
Some laptops will display on an external monitor without you having to do anything.
If you get no video on an external monitor, some laptops have a key combo that you must press to toggle the display to external video only / sometimes both / built in display video only - see the Owner's or User's manual for the model.
If there is nothing wrong with your AC adapter or it's connection and the jack in the laptop.......
Laptop main batteries usually work as they should for a year or so, then they begin to rapidly deteriorate. From what I've seen, by two years they cannot be charged to anywhere near their full capacity, and it gets worse after that.
They often develop internal shorts when they are older. If the battery gets HOT rather than just warm after you have attempted to charge it for at least a half hour, or after you have been using the laptop for a while with the AC adapter plugged in, it's definitely internally shorted and you must replace it. Internally shorted batteries getting too hot have been known to cause the laptop to catch on fire.
In the case of this circa 1999 600E model, your laptop should start up with only the AC adapter connected to it, if there's nothing wrong with the AC adapter, it's cord, it's DC plug, the DC jack on the laptop, or the power circuits inside the laptop.
ThinkPad 600/600E Hardware Maintenance Manual:
Lots of info in that, including what the leds are for and what they show, and how to check the battery and the AC adapter output.
See response 2 in this - try cleaning the contacts on the ram modules, and making sure the modules are properly seated:
For a laptop, or netbook, you must remove both its main battery and AC adapter before you do that.
If someone has installed ram that isn't 100% compatible with using it in the mboard, the mboard may not boot all the way and there may be no mboard beep(s).
It is easy to test for incompatible ram that has caused your mboard to fail to boot.
Remove the AC adapter's connection, and the main battery.
Remove all the ram.
Connect at least the AC adapter's connection, or that and install the main battery .
(If you're not certain the main battery is okay, try not installing it.)
Try to boot.
If nothing else is wrong, you will get no video but you will hear a pattern of beeps that indicate no ram is installed, or a ram problem.
E.g. for an Award bios or a bios based on one, that's often a beep of about a half second, silence for a half second, a beep of about a half second, silence for a half second, continuously.