Ma / Mas Measurement; Troubleshooting; Checking The Line Voltage - Siemens MULTIMOBIL 2.5 Troubleshooting Manual

Higher kV indicates error in kVsoll / kV sensing / kV regulator.

7.5.2 mA / mAs Measurement

mAs measurement could be carried out either by mAs-meter or by electrical
measurement.
7.5.2.1 mAs-meter
Remove mAs link on D920.
Insert mAs-meter leads in the banana sockets mA+ and mA- on D920.
Set meter in the mAs mode at 200mAs.
Set exposure parameters as 60kV 20mAs.
Release an exposure.
The meter will read 19 - 21mAs.
Repeat for exposure parameters 90kV 16mAs.
The meter will read 14.4 to 17.6mAs.
The actual tube current can be measured by setting the meter in mA mode.
Set the exposure parameters as 60kV 50mAs.
Release an exposure.
During the exposure, the meter will read 23 - 27mA.
7.5.2.2 Electrical
Connect oscilloscope at D915.TP.JR.
Set exposure parameters as 60kV 2.5mAs.
Release an exposure.
The recorded waveform will read 1.58 - 1.62V.
The exposure time will be 76 - 84mS.
Lower mA indicates error in mAsoll / mAsensing / mA regulator circuit.
Higher mA indicates error in mAsoll / mA sensing / mA regulator OR Low kV.
Incorrect mAs indicates Error in timer.
7.6

Troubleshooting

In case of CODEs which Impair radiography, perform the following checks.

7.6.1 Checking the line voltage

Measure the supply voltage at site using the digital multimeter.
Ensure that the supply conditions
• Voltage
• Frequency
• Mains Resistance
are within limits as specified in the Technical Specifications for the Unit.
Switch the Unit ON
Siemens Ltd. Med India Version 6.0
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