Service Manual
Service Instructions
Siemens Ltd. Med India
Version 6.0
Copyright
SIEMENS LTD. All rights reserved. For internal use only
7-4
Signal
Measuring Point
Range
Adjustment
IH
D915.TP. IH
During Standby
2 V
±
0.1 V
D915.P5
During Preparation
3.8 V
±
0.3 V (For critically
damped mA)
Fmax
D915.TP.REG point
during exposure
9.2 kHz
±
0.3 kHz
D915.P4
7.4
HT Check
7.5
Calibration
It is advisable to re-calibrate the unit in case of undershoot or overshoot observed in
the mA waveshape.
Recalibration is required when the single tank is replaced.
7.5.1 kVp Measurement
The kVp measurement can be carried out either by kVp-meter or by electrical
measurement.
7.5.1.1
kVp-meter
Switch the unit ON.
Insert the kV sensor into collimator channel and connect the cable to the meter.
Open collimator flaps such that the sensor is well covered by the field.
Set the kVp meter at 12pulse and 55-85kV range.
Set exposure parameters as 60kV 20mAs.
Release an exposure. The radiation LED will light up during exposure.
The meter will read 57-63kV.
Repeat with meter setting 77-150kV and exposure parameter setting as 90kV 20mAs.
The meter will read 85.5-94.5 kV.
7.5.1.2
Electrical
Connect oscilloscope at D915.TP.KV.
Set the exposure parameters as 60KV 2.5mAs.
Release an exposure.
The recorded waveform will read 2.85 - 3.15V.
Repeat with 90kV 1.6mAs.
The recorded waveform will read 4.27 - 4.75V.
Lower kV indicates error in kVsoll / kVsensing / kV-regulator OR high mA.
WARNING
Use Radiation Protection.
Presence of High Tension.