X24 can't boot unless connected to AC

[AlanHK]

Recently my X24 won't boot up if it's not connected to AC power.
If I boot up when plugged in, and then disconnect, it will run on the battery.

The battery isn't new but has about an hour of life in it.

Could the CMOS battery be dead or too low?
Or what?

[RealBlackStuff]

In older TPs the CMOS battery seems to be more important apparently than in today's models.
Replace it, they are quite cheap.
Or reuse the wire harness and get a matching (thin)CR2016, (medium)CR2025 or (thick/standard)CR2032 battery (all 3V).

[AlanHK]

In older TPs the CMOS battery seems to be more important apparently than in today's models.
Replace it, they are quite cheap.

It's not a problem to replace, if that's the most likely cause.
I'll get one next time I'm in the computer mall (other side of the city, so I don't get there often).

Is there any way to tell?
I have a multimeter, could check the voltage as it seems quite accessible.

[RealBlackStuff]

It's no guarantee that that is your problem, but I've come across similar situations a few times with older TPs.
You could also try another 16V IBM adapter (56W or 72W), before taking the thing apart to check fuses.

[AlanHK]

It's no guarantee that that is your problem, but I've come across similar situations a few times with older TPs.
You could also try another 16V IBM adapter (56W or 72W), before taking the thing apart to check fuses.

Nothing wrong with the adapter, or the TP when it's plugged in.

But it will not boot -- completely dead -- when unplugged, despite the main battery being fully charged.