IBM eserver pSeries 690, Service Manual

Page: 932 / 1134

4. Press the toggle switch on the LGA-ST forward to the MCM/L3 PWR/GND position. This action will test
the L3 modules for power-to-ground shorts. Observe the lit LEDs on the LGA-ST and take the
corresponding following actions:
Green L3 LED is lit
This is a pass state. No further action is required.
Amber L3 LED is lit
This is a fail state. There might be a short between one of the two L3 voltages and ground,
which is a failing condition, or the combination of memory books, I/O books, and L3 cache
modules in parallel might be creating a low resistance.
Complete the following steps to correct this condition:
a. Disengage memory books followed by I/O books one at a time.
b. Repeat step 2a on page 914 through step 2h on page 915 until either the L3 test results in
a pass state, or all memory and I/O are disengaged and the L3 test remains in a fail state.
c. If the L3 module test remains in a fail state after all memory and I/O are disengaged,
remove the L3 module and inspect the interposer for shorts.
d. Reinstall the L3 module once and repeat the test. If the fail persists, replace the L3
module.
Green MCM LED is lit
This is a pass state. No further action is required.
Amber MCM LED is lit
This is a fail state. There might be a short across the MCM voltage and ground. Perform the
“Method 3. Testing MCMs and Pass Through Modules for a Short Circuit” on page 895 and
correct any short conditions before powering on.
5. Place the toggle switch into the L3 PWR/PWR position.
Green and Amber MEM LEDs are not lit
Power is removed from these circuits when the switch is in the L3 PWR/PWR position.
Green L3 LED is lit
This is a pass state. No further action is required.
Amber L3 LED is lit
This is a fail state. There is a short between the two L3 power domains. Complete the
following steps to correct this condition:
a. Remove the L3 module and inspect the interposer for shorts.
b. Reinstall the L3 module once and repeat the test. If the fail condition persists, replace the
L3 module.
6. Install another L3 module and repeat step 3 on page 915 through step 5 until all required L3 modules
are installed.
Shorts Test Qualified Service Meters and Fail Criteria
Manufacturer Model Range Accuracy @ 1.0
ohms or less
Fail Criteria
Fluke 8060A 200 Ohms +/-0.04 +0.40
Fluke 8060A/AA 200 Ohms +/-0.04 +0.40
Fluke 8062A 200 Ohms +/-0.04 +0.40
Fluke 187 500 Ohms +/-0.10 +0.40
Fluke 189 500 Ohms +/-0.10 +0.40
Fluke 83 (original models) 400 Ohms +/-0.10 +0.40
Fluke 85 (original models) 400 Ohms +/-0.10 +0.40
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Eserver
pSeries 690 Service Guide