Instruction manual

7 MAINTENANCE AND CALIBRATION
7.1 GENERAL
A regularly scheduled preventive maintenance schedule is recommended for the
BOS/S series of power supplies. This should consist of wiping the wrapper to prevent
dust build up in the air vents and the cabinet which the BOS/S is installed.
7.2 CALIBRATION
The BOS/S power supplies are fully calibrated at the factory and do not normally
require recalibration.
The following are the only calibrations that may be performed in the field. If other
calibration is required, please contact Electronic Measurements’ Customer Service
Department.
Equipment needed for calibration: Digital Voltmeter, at least 4-½ digits. Shorting bar
for the output terminals.
7.2.1 THE INTERNAL ±10VDC REFERENCE
Set the DVM on the volt scale. Connect the ground lead to TP1, connect the
plus lead to TP2 on the A100 Control Board. Adjust R38 until the DVM is
+10.000VDC. Allow up to 5mV for error. Connect the positive lead to TP3 and
adjust R39 until DVM reading is -10.000. Again, allow up to 5mV for error.
7.2.2 DIGITAL AND ANALOG METER CALIBRATION
The analog meters should be exactly zero centered when the power supply is
off. If the meters are not zero centered, an adjustment on the meters’ front
face should be made. Simply rotate the adjustment screw direction until the
meter shows zero volts or zero amps. Digital meters require no zero
adjustment.
7.2.2.1 Voltmeter
Once the METER ZERO CALIBRATION and the internal ±10VDC
reference has been calibrated, the meters on the front panel can be
calibrated.
With the BOS/S in an open circuit, VOLTAGE MODE and INTERNAL
control, turn the VOLTAGE CONTROL POTENTIOMETER on the
fornt panel fully clockwise. Measure voltage at the output to verify full
scale voltage is obtained. Adjust R44 on the A100 PCB until correct
reading on voltmeter is obtained.
7.2.2.2 Ammeter
With BOS/S in a short circuit, CURRENT MODE and INTERNAL
control, turn the CURRENT CONTROL potentiometer on the front
panel fully clockwise. Adjust R80 until correct full-scale reading on
ammeter is obtained.
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83-469-001 Rev. B