GE Brivo OEC 715, Service Manual

Page: 232 / 551

Calibration
4-21
4.4. mAs Measurement and Calibration
4.4.1. mAs Measurment and Accuracy Check
Remove J46 jumper on extend board. Connect the probes of ampere meter to TP222 (+) and TP210 (-) on
extend board. Connect the mAs meter to ampere meter in serial.
Take exposure by the parameters below. The error of mAs should be within
±
10%.
kV, mAs Minimum (mAs) Maximum (mAs)
40KV, 40mAs 36 44
60KV, 20mAs 18 22
80KV, 10mAs 9 11
110kV, 1mAs 0.9 1.1
4.4.2. mAs Calibration
1. Take exposure at 80kVp, 20mAs. Adjust POT2 on MCB board until the measured mAs value is
20.0mAs
±
1mAs.
2. Check mAs accuracy according to section 4.4.1.
After the calibration, connect the jumper to J46 on extend board.
3. After the calibration process completion, remove the extend board and recover the system.
4.5. X-Ray Generator Warm-up
This procedure is used to improve the life of the X-Ray generator. It is only required if the Generator is not
powered for more than 3 months.
1. Power on the system
2. Close the collimator IRIS and place a lead shield in the X-Ray beam to protect the Image
Intensifier and CCD camera.
3. Select the Manual Fluoroscopy mode. Set the kVp value to 60 kVp@1mA. Take an exposure for 3
minutes.
4. Wait for 5 minutes after exposure.
5. Set the kVp value to 80kVp@1mA and take an exposure for 3 minutes.
6. Wait for 5 minutes.
7. Power off the system.