OEC 9800C-Arm, Руководство по обслуживанию

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kV Generation
Adjustments
For details of these adjustments, refer to the Calibration chapter in this manual.
1. Stability Adjustment, HV Supply Regulator PCB, TP48, Pot R83.
2. Dead Time Adjustments, HV Supply Regulator PCB, TP70-71, 41-46, Pots R137, R84. If the condition of the dead time
adjustment is not known, turn pots 10 turns clockwise to the safe position.
3. Sync Adjust, HV Supply Regulator PCB, Pot R139.
4. Ramp Adjust, HV Supply Regulator PCB, Pot R109, TP57.
kVp Accuracy
1. Set the generator to produce a 100kVp nominal technique setting. This should result in a voltage at the X-Ray Controller’s
DAC of 6.5934V. This will be reduced to 6.4423V between KVP_CNTL and KVP_CNTL_REF at the HV Supply Regulator
PCB. The mA setting should be 0.2mA.
2. Verify the output voltage at TP25, KVP_CNTL_TP to be 6.5596V
±
2%.
3. The KVP_PULSE* voltage at TP19 should be -6.5577V
±
2%.
4. The KVP_SEN_TP voltage at TP21 should be 6.5906V
±
2%.
5. The kVp value measured should be 100kVp
±
3%.
Note: Non-invasive kVp meters will generally give inaccurate readings because of the level of filtering in the 9800 system and
various other factors. Measurement is generally better at higher mA values, e.g. above 3mA. Although we do not
typically use Dynalyzers in the field, we have confirmed that the actual kVp developed is typically within 1kV of the
selected value, while non-invasive meters range from –15% to +10% of the correct kVp especially at low mA techniques.
They also tend to give inconsistent results when placed at different locations in the X-ray beam.
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