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. The following procedure must be ¦
¦ performed during this period. If the system is already in suspend ¦
¦ 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.
PICTURE 10
+------------------------------------------------------------------------+
¦ ¦ ¦ ¦ V dc Min. ¦ V dc Max. ¦
¦ Connector ¦ Pin ¦ Signal ¦ ¦ ¦
+-------------+--------------+--------------+--------------+-------------¦
¦ CN5 ¦ ¦ ¦ ¦ ¦
¦ ¦ 1 ¦ VCCA ¦ +4.7 ¦ +5.3 ¦
¦ ¦ 3 ¦ VCCB ¦ +4.7 ¦ +5.3 ¦
¦ ¦ 7, 8 ¦ GND ¦ - ¦ - ¦
¦ ¦ 9, 10 ¦ GND ¦ - ¦ - ¦
¦ ¦ 13 ¦ +20 V dc ¦ +19.0 ¦ +21.0 ¦
¦ ¦ 21 ¦ POWER_GD ¦ +4.0 ¦ +5.3 ¦
¦ ¦ 32 ¦ POWER_ON# ¦ 0 ¦ +0.5 ¦
¦ ¦ ¦ ¦ ¦ ¦
+-------------+--------------+--------------+--------------+-------------¦
¦ CN7 ¦ 2 ¦ VCCG ¦ +4.7 ¦ +5.3 ¦
¦ ¦ 23, 24 ¦ GND ¦ - ¦ - ¦
+------------------------------------------------------------------------+
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). If the voltage is
correct, replace the voltage converter.
If any of the measured voltages 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
¦ Copyright IBM Corp. 1991
5.7 - 1
Summary of Contents for PS/2 N51 SX HMR
Page 34: ......
