Quantum ODYSSEY HF Series, Service Manual

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Appendix B Calibration (DiRex System)
HF Series X-ray Generators - Service Manual Revision W
Quantum Medical Imaging, LLC
B-37
MA Calibration
This procedure calibrates the generator to verify accurate system measure-
ment of tube current (mA). Current measurement accuracy is verified using a
pre-calibrated mAs meter (Dynalyzer or equivalent) as a benchmark. Ensure
precision of the measurement instrument is sufficient enough to assure gen-
erator accuracy requirements can be met.
An oscilloscope may be used for mA measurement, however, it likely will not
be precise enough to assure generator mA accuracy. To use an oscilloscope
for mA measurement, connect scope leads between test point TP7 on KVP
Control Board A2 (AY40-003S1) and ground. Set scope for 1.0 volt/division,
and 50 ms/division time base. This will give a 100 mA/volt equivalent for mA
measurement (see Figure B-23a for sample mA measurements using scope).
Figure B-23a. MA Measurement Using an Oscilloscope
Proceed as follows:
WARNING! To avoid injury to personnel, ensure
that system power is removed prior to making
and removing any electrical connections.
1. If not already done so, a kVp bleeder tank should be connected in series
between tube and High-Voltage (H.V.) Transformer A17. If using a mAs
meter, connect the mAs meter between pins A17P1-9 and A17P1-10 on
H.V. Transformer A17. This connection is made by removing the two
green/yellow wires connecting A17P1-9 and A17P1-10 to the ground stud
on top of the H.V. Transformer (see Figure B-22) and connecting the
removed wires to the mAs meter. (Note: The MAS meter should remain
connected throughout calibration.
These wires must be re-connected
when finished calibration
.)