Olympic 50 - Page 10

The cap screws attaching the main platform to the chassis
(Fig. 4-5) require 4-6 in-lb torque.
' Note: When reinstalling the weighing platform, ensure the
channel connected to the right load cell is square and the
swing arms move freely.
CAUTION: The Smart Scale must be recalibrated when-
ever is has been disassembled and reassembled. See
page 4-1
Symptoms and Suggested Tests
For Test Point voltage values, refer to the Test Point Chart
in Fig.4-10.
Scale will not come on and Zero:
1. If walking dashes are displayed, there are two possible
causes: .
a. The signal is beyond the zero capture range. This
could be caused by a bad load cell or a power problem.
Remove the main platform assembly (in disassembly pro-
cedure) so the aluminum platform is exposed. This will
also expose the front edge of the Main Board with its test
points (Fig. 4-10).
Spacer
- Check power voltages at test points TP3, TP5 and TP11
{with respect to ground, TP10).
- Check that the zero offset voltage is correct at TP1.
Typical value with the main platform assembly removed
will be around -1.2 volts.
- Check that the signal atTP2 is correct. Typical value with
the main platform assembly removed will be about -1.1
volts but the A/D should be able to capture anything
between -2.00 volts and +2.00 volts.
- Check that the A/D reference voltage at TP6 is correct—
around 1.00 volts.
b. The signal is too unstable to acquire zero. This could
also be caused by a power problem.
Check the +5Va and the -5Va at test points with a scope
and verify that there is no excessive noise on these lines.
If voltages are correct, check noise on the signal at TP2.
Test Point Description
TP1 Zero offset. -1.2 volts with platform ass'y. off
TP2 Analog signal input from amps to filter & A/D
TP3 +5 Va Analog +5 volts for load cells, amps, A/D
TP4 Chopper clock
TPS -5 Va Analog -5 volts for amps & A/D
TP6 A/D ref voltage. 1.00 volts normal
TP7 Vin (Battery voltage) or +11.25 Vdc if on AC.
TP8 Not very low battery signal
TP9 Not low battery signal
TP10 Ground
TP11 +5 Vd Digital +5 volts for pC, displays, etc.
TP12 =| Not On/Off switch signal input
TP13 Not Recall switch signal input
Fig. 4-9 Weighing Platform Spacer
SS50-N1-220V(B09)
Fig. 4-10 Test Point Voltages
Page4-4