T Scale M503 Series - 10.4 Check the Load cell; 10.5 Check PCB Voltages

M503 Series Wheelchair Scales Technical Manual
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10.4. Check the Load cell
 Remove power from the system, and disconnect the PCB from the Load
cell
 Check the moisture, or foreign material inside.
 Make sure all leads are connected and correctly.
 Check load cell for proper input and output resistances
Load Cell Connections
Signal + Green
Supply + Red
Signal - Black
Supply - White
Shield
Measuring Points
Resistance
Red (+ Exc) to White ( –Exc)
420 ±20Ω
Green (+Sig) to Black ( –Sig)
350Ω ±5Ω
10.5. Check PCB Voltages
If the problem is in the PCB, use a multimeter to check the following voltages
10.5.1 AC Power
Check the AC power socket out put voltage.
 Voltage must be a -20% and +10% of the normal AC voltage.
10.5.2 Adaptor Voltage
Check the adaptor output cable connecter voltage
 Voltage must be minimum 9VDC and maximum 15VDC