natus OLYMPIC SMART SCALE 50, Instruction Manual

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6-8 OLYMPIC SMART SCALE Model 50/51 Instruction Manual
Repair Procedures
Testing the Membrane Switch Panel
Test the membrane switch panel if the
AVERAGE
/
UNLOCK
,
KG
/
LB
, or
ZERO
do not function.
Required Items:
„
Allen wrench
„
ESD protection
„
Jumper wires (x2)
„
Voltmeter
To test the membrane switch panel:
1
If the scale is on, press
ON/OFF
to turn off the scale, then unplug the
power cord.
2
Disassemble the scale (see page 6-2).
3
Disconnect the ribbon cable connector from the display PCB (see Figure 6.6).
Figure 6.6 Disconnecting the ribbon cable connector
4
Verify that the membrane switch panel is properly connected.
5
Using two small jumper wires, check the resistance of the malfunctioning
switch at the corresponding pin on J2 of the display PCB (see Table 6.1).
6
Using the ground reference point of either pin 5 or 6, check the resistance.
The resistance should be less than 50
Ω
(circuit closed) when pressed —
„
If not, replace the membrane switch panel.
Display PCB Mounting screws (x4)
Ribbon cable connector
NOTE
#
If the
KG/LB
disabling switch has been activated (see page 2-1),
KG/LB
will be disabled
and the scale will only display kilograms.
Table 6.1 Control panel button pin out
Switch J2 pin on display PCB
Common (ground)
5, 6
Zero
2
Average/Unlock
4
Kg/Lb
3
On/Off
1
Recall
7