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5.7 Checking the Voltage Converter
Use the following procedure to isolate the voltage converter from the
problem.
Note:
If the problem occurs only when using the system with a good
battery pack, replace the voltage converter.
1.
Turn off the system power switch.
2.
Turn off all attached devices and disconnect them from the system.
3.
Unplug the AC adapter from the system.
4.
Remove the battery pack and the bottom cover.
5.
Disconnect the standby-battery connector and the flexible cable from
connector CN6 on the voltage converter.
6.
Turn on the system power switch.
7.
Plug the AC adapter into the system.
+--- Attention ------------------------------------------------------+
¦
¦ The system goes into suspend mode in about 20 seconds after
¦ plugging in the AC adapter.
¦ performed during this period.
¦ mode, unplug the AC adapter and plug it in again to reactivate it. ¦
¦
+--------------------------------------------------------------------+
8.
Check the voltages of the voltage converter using the following table.
+------------------------------------------------------------------------+
¦
¦
¦ Connector
¦ Pin
+-------------+--------------+--------------+--------------+-------------¦
¦ CN5
¦
¦
¦ 1
¦
¦ 3
¦
¦ 7, 8
¦
¦ 9, 10
¦
¦ 13
¦
¦ 21
¦
¦ 32
¦
¦
+-------------+--------------+--------------+--------------+-------------¦
¦ CN7
¦ 2
¦
¦ 23, 24
+------------------------------------------------------------------------+
If all the voltages are correct, the voltage converter is good.
If +20 V dc is not correct, check the output voltage of the AC adapter
(see "Checking the AC Adapter" in topic 5.1).
correct, replace the voltage converter.
If any of the measured voltages except +20 V dc is not correct,
replace the following FRUs one at a time to correct the problem.
1.
Voltage converter
2.
System board
3.
I/O panel assembly.
Note:
Reconnect the standby-battery connector and the flexible cable that
were removed in Step 5 before leaving this procedure.
IBM PS/2 Model N51 SX HMS
Checking the Voltage Converter
The following procedure must be
If the system is already in suspend ¦
PICTURE 10
¦
¦ V dc Min.
¦ Signal
¦
¦
¦
¦ VCCA
¦ +4.7
¦ VCCB
¦ +4.7
¦ GND
¦
-
¦ GND
¦
-
¦ +20 V dc
¦ +19.0
¦ POWER_GD
¦ +4.0
¦ POWER_ON#
¦ 0
¦
¦
¦ VCCG
¦ +4.7
¦ GND
¦
-
If the voltage is
¦ Copyright IBM Corp. 1991
5.7 - 1
¦
¦
¦
¦
¦ V dc Max.
¦
¦
¦
¦
¦
¦ +5.3
¦
¦ +5.3
¦
¦
-
¦
¦
-
¦
¦ +21.0
¦
¦ +5.3
¦
¦ +0.5
¦
¦
¦
¦ +5.3
¦
¦
-
¦
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