Huawei TP48200A-D17B3 Troubleshooting Manual page 40

TP48200A-D17B3
Troubleshooting Guide
Step 1 Remove the cover plate of the power subrack and the protection board of the AC detection
board using a screwdriver.
Step 2 Set the multimeter to the AC mode and measure the A-phase AC input at port J1 (pin 1 and
pin 4) of the board.
Step 3 Remove the cable connected to port J2 and wrap the connector with ESD tape, and then
measure the small AC signal sent to the signal transfer board at port J2 (pin 1 and pin 5 from
the right).
Step 4 Calculate the AAC small signal.
The calculation formula is AAC small signal = AAC input x 510/400 K. For example, if the
measured AAC input at port J1 is 220 V, then the measured AAC small signal should be about
280 mV. If the AC signal is incorrect, the AC detection board is damaged.
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Issue 03 (2013-05-06) Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd
5 Common Faults
34