Method 3. Testing L3 Cache Modules For A Short Circuit - IBM pSeries 670 Service Manual

Method 3. Testing L3 Cache Modules for a Short Circuit

You must test the LGA-ST unit before you can begin testing the MCM and pass through modules for a
short circuit with the following steps:
1. Plug the LGA-ST test head on the test box into the 9-pin female self-test D-shell, located on the
LGA-ST control box, which looks similar to the following:
1 Test head
2 Test box
3 Jack screw
4 Control box
2. Perform the following steps to ensure that the LGA-ST battery is charged and that the LGA-ST is
functioning properly to detect shorts:
a. Place the toggle switch into the MCM/L3 PWR/GND position and observe the lit LEDs. Refer to the
following table for valid LED states:
MCM
Toggle Switch Green
Position LED
Forward (to the Off
MCM/L3
PWR/GND
position)
b. Place the toggle switch into the L3 PWR/PWR position and observe the lit LEDs. Refer to the
following table for the valid LED states:
Toggle Switch MCM
Position Green LED
Backward (to Off
the L3
PWR/PWR
position)
MCM
Amber L3 Green
LED LED
On Off
MCM
Amber L3 Green
LED LED
Off Off
5 Toggle switch
6 Self-test D-shell
7 Battery access
L3 Amber Battery Low
LED Amber LED
On Off
L3 Amber Battery Low
LED Amber LED
On Off
Chapter 9. Removal and Replacement Procedures
Action
1) If Low Battery LED is
on, or if no LEDs are
lit, replace the battery
before proceeding.
2) If the battery appears
to be functioning and
the LEDs are not lit as
shown in this table, the
LGA-ST is defective.
Replace the unit
before proceeding.
Action
1) If Low Battery LED is
on, or if no LEDs are
lit, replace the battery
before proceeding.
2) If the battery appears
to be functioning and
the LEDs are not lit
as shown in this
table, the LGA-ST is
defective. Replace
the unit before
proceeding.
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