NHM-7
Troubleshooting and Tuning Instructions
PAMS Technical Documentation
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Keypad fault 3
Is volume DOWN key
working ?
Measure ROW0
line from S302.
Is it ~1.8 V ?
No
Check S301,
S302, lines.
If OK change
Z301.
If still FAIL
change UPP
No
Measure COL4
from S302 when
S302 is pressed
Is there
50us pulse ?
Check S302
and COL4 line.
If OK change
Z301.
If still FAIL
change UPP
Yes
Change UPP
No
Yes
END
Keypad
faults 3
Yes
Is volume UP key working ?
Measure ROW0
line from S301.
Is it ~1.8 V ?
Check S301,
S302, lines.
If OK change
Z301.
If still FAIL
change UPP
No
No
Measure COL1
from S301 when
S301 is pressed
Is there
50us pulse ?
Yes
Check S301
and COL1 line.
If OK change
Z301.
If still FAIL
change UPP
No
Change UPP
Yes
Yes