Optima MR450w BASE 1.5T System Service Methods
5690012-2EN Revision 3
Object ID: 00000018WHA30B49BGYZ
Topic ID: id_2002056 Version: 7.0
Date: Feb 21, 2021 9:03:29 PM

Calibrating RF Amplifier and UPM

Prerequisites


Personnel requirements
Required persons	Preliminary requirements	Procedure	Finalization
1	-	45 minutes	5 minutes


Tools and test equipment
Item	Quantity	Part number	Manufacturer
RF Power Measurement Kit	1	Either 5307511-2 or 5307511-3 (Bird wattmeter)	-
Digital Voltmeter (DVM)	1	46-194427P284	-


Required conditions
Before beginning this procedure, make sure that the exciter has been on for at least 20 minutes.

Safety

Before working in any GE Healthcare MR suite or performing any GE Healthcare service procedure, you must:

Have read and understood all hazard conditions and safety requirements in the latest revision of the GE Healthcare MR Service Safety Manual (5452735).
Have successfully completed all relevant GE Healthcare Environmental Health and Safety (EHS) courses (or for non-GE employees, equivalent workplace training courses).
Comply with all site-specific training and workplace safety requirements.

If you have any safety concerns at any time, do not begin work or immediately stop work and move to a safe location. Immediately contact your supervisor or site safety officer for instructions on how to proceed.

Notice

Possible equipment damage

Operating the RF amplifier with an improper load can cause permanent damage to the amplifier.

Do not operate the RF amplifier with an improper load connected to its output.

Notice

Possible component damage

Hardware and phantoms left in the magnet bore can cause component damage.

Prevent coil and associated switch damage by removing all phantoms and hardware (such as head coil or surface coil) from the magnet bore.

Notice

Possible component damage

If you connect or disconnect the wattmeter sensor while the meter is ON, component damage can occur.

Do not connect or disconnect the wattmeter sensor while the meter is ON. Always turn the meter OFF before plugging in or unplugging the sensor.

About this task

This procedure provides instructions to calibrate the maximum power for the RF amplifier and also calibrate and do a check of the power monitor calibration for each channel using the UPM Tool.

Use the UPM Tool to process each channel. For example, when you select head mode, the tool executes the RF amplifier calibration and, if the amplifier passes, it proceeds to the UPM calibration and then to the functional check. The process is order-dependent.

For RF amplifier calibration, process the following in order:

Body channel .
Head channel.

Buttons change color to keep track of task status:

Grey: Not started.
Blue: In progress.
Red: Error encountered or failed specs.
Green: Successfully completed and passed.

Click File for the following menu options:

View Results: Open previous results file.
View Config: View RF and power monitor configuration file details.
Backup Cal Files: Backup upm*Cal.cfg files.
Restore Cal Files: Restore upm*Cal.cfg files.

Click Tools for the following menu options:

Reset Average Power: Run utility to reset power monitor power.
Check Cal Status: Display status of current power monitor calibrations.

For each channel, adjust the RF amplifier output power first, then calibrate UPM forward and reflected power, and finally run a UPM functional check.