User Guide

NHM-4
CCS Technical Documentation
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Keypad troubleshooting 1
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Keypad
faults
Is the power key OK ?
Measure voltage
from S302
Is it HIGH ?
No
Check R301,
C312, S302
and line.
If OK –>
Change UEM
No
Measure voltage
from S300 when
power key is pressed.
Is it HIGH ?
Yes
Yes
Change S302
Phone is
jammed
No
Keypad
faults 2
Yes