TTI EX752M, Service Manual

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Voltage Regulation
Connect the DMM (set to Volts) across the output, no load, output ON.
Adjust voltage controls for a reading of 18.xxxx on the DMM; note exact reading.
Connect load and adjust it to give an output current of 2.00A on the Amps display. Adjust VR9/109
(differential voltage gain) until the external DMM matches the previous reading.
Mode B (75V/4A)
With both outputs OFF select Mode B (75V/4A). Set the voltage and current controls to maximum
and check that the current display (preset maximum current) reads
≥
4.05 Amps. Connect the
rheostat, switch the output ON and adjust the load until the CC LED is just ON; check that the
current display (measured output current) matches the preset current ± 0.05 Amps.
Mode C (150V/2A)
With no loads connected and both outputs OFF select Mode C (150V/2A). Switch the output ON
and check that the reading on the Volts display (measured output volts) is
≥
150.1V. Switch the
output OFF and adjust VR111 to give the same reading on the Volts display (preset output volts).
Noise Measurements
Differential and common-mode noise checks can be made using the arrangement below. Keep all
unscreened connections as short as possible.
Make measurements with the output fully loaded. Measure differential and common-mode noise
one at a time on a 20MHz TRMS voltmeter or use a 20MHz bandwidth-limited scope for peak-to-
peak measurements.
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