Red

Black

Wire

Voltage (V dc)

 

 

Red

+2.9 to+3.3

 

 

Black

Ground

 

 

Ÿ If the voltage is correct, replace the system board.

ŸIf the voltage is not correct, the backup battery ha

been discharged. Replace the backup battery.

ŸIf the backup battery discharges quickly after replacement, replace the system board.

Checking the

Standby

Battery:

Be careful not

to cause

a short

circuit

when measuring the voltage.

1.Power-off the computer and unplug the AC Adapter from the computer.

2.Remove the standby battery.

3.

Measure

the

voltage

of

the

standby

battery.

 

 

 

Ÿ

If

 

the

voltage

between red and black is 3.5 V dc

 

 

or

greater,

the

voltage

is

correct. Go

to

Step

9

 

 

on

page 33

to verify

standby battery

operation.

 

Ÿ

If

 

the

voltage

is less

than

3.5

V dc, go

to

the

 

 

next

step.

 

 

 

 

 

 

 

 

 

4.

Plug the AC Adapter

into

the

computer

and

power-on

 

 

the

computer.

 

 

 

 

 

 

 

 

 

5.Measure the output voltage at the connector on the system board.

32 IBM Mobile Systems HMM