Gendex ORTHORALIX 9200 Service Manual page 67

Service Manual
R12 6.
Check the exposure time.
The exposure time can be measured with the oscil-
loscope using the solar cell or monitoring the mA
be calculated when the signal reaches 25 % of the
maximum value (raising and falling edges); toler-
ance: 20 ms or ± 1% (whichever the larger).
R12 7.
Check reproducibility.
Dismount the collimator.
Place the dosimeter at 20 cm. from the focus.
Inhibit the movements during the exposures.
Select 70 kV 10 mA 0.80 s.
and enter the value of the radiation dose after each
R12 8.
Check the radiation leakage.
any direction, and check that the dose rate values for
the combination tubehead and collimator are lower
than 250 µGy/h (28mR/h) as specified.
The prescribed duty cycle factor (1/20) shall be
taken into account in the calculations, in order to
obtain the correct dose rate figure.
S12 9.
Check the earth resistance.
Orthoralix requires a fixed installation, therefore the
resistance between any exposed conductive part
and the earth terminal of the mains input contactor
has to be lower than 0.1 . Disconnect the unit from
the mains and measure with the Bonding tester.
S/R12 10.
Check the earth leakage.
using the circuit arrangement shown in the fig. be-
low:
Printed on: 20 Apr 2012, 04:59:40 pm; Printed by: UWE.ZELLER
R = 1K ±1%
C = 0.15 F ±5%
N = neutral terminal
PE = protective earth terminal
T = K1 insulation transformer
Check that the results conform to the table below:
S1 S2 S3
OFF OFF ON
OFF ON ON
ON OFF ON
ON ON ON
OFF OFF OFF
OFF ON OFF
ON OFF OFF
ON ON OFF
during exposure
12 1.
Check the reset position.
R12 2.
Check the centering of the X-ray beam on the sec-
ondary slit.
R12 3.
Check during the exposure, on the system and on
the remote control, that the X-ray lights are on and
that the buzzers sound.
R12 4.
Check the centering of the system making a pan-
oramic exposure with the image quality phantom.
12 5.
Check the adjustment of the centering lights.
R12 6.
Check the ceph centering (X-ray field and ear
plugs).
MAX. LEAKAGE CURRENT
(mA)
< 5
< 5
< 5
< 5
< 10
< 10
< 10
< 10
< 10