Discovery MR750w and SIGNA™ Architect T 3.0T System Service Methods
5690002-2EN Revision 4
Object ID: 00000018WIA3021AA50GYZ
Topic ID: id_2026839 Version: 1.1
Date: Jun 22, 2020 9:54:26 AM

Setting up and calibrating UPM - MNS

Prerequisites


Personnel requirements
Required persons	Preliminary requirements	Procedure	Finalization
1	-	30 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 Multimeter	1		-
3.0T 31P TR Switch (available on site with customer)	1	2354050 (non-RoHS) 5409918 (RoHS)	-

Table 1. Safety

DANGER

Electrocution hazard

Hazardous voltage levels exist throughout the UPM cabinet.

Make sure that the RF amplifier is disabled when configuring the calibration tools.

About this task

This document provides instructions for both amplifier calibration and UPM calibration. It also covers both the AMT and CPC amplifiers.

The AMT amplifier has cable connections at the rear of the cabinet. The CPC amplifier has cable connections at the top of the cabinet.

If you are replacing a UPM board only (rather than performing a full MNS setup), start with Setting up software tool to calibrate UPM - MNS forward power .

Topic ID: id_SL2671384-1046254

Disable VSWR fault detection in AMT amplifier

About this task

This procedure is for the AMT amplifier only. For the CPC amplifier, proceed to Amplifier forward power calibration .

Procedure

Perform LOTO on the RF amplifier and PEN cabinet to remove power to the MNS amplifier. See the MR Service Safety Manual , PN 5452735.
Remove the top panel from the MNS amplifier cabinet.

Figure 1. Top panel of AMT MNS amplifier cabinet
Remove the top cover of the controller module in the MNS amplifier cabinet.

Figure 2. Top cover of controller module
Locate the SMA cable connections to J7 and J8 on the controller module PCB. Remove the connections and move the cables away from the PCB. Restrain the cables with tape, if necessary.

Figure 3. J7 and J8 on controller module PCB
Replace the top panel of the MNS amplifier cabinet.
Remove LOTO (see the MR Service Safety Manual , PN 5452735) and reapply power to the MNS amplifier.

Topic ID: id_SL1761398-1046254

Amplifier forward power calibration

Procedure

Inhibit TR faults by moving SW2 on the driver module in PEN cabinet to the TR Disable position.

Figure 4. Driver module switches
Set RF Enable S2 on the MNS exciter to Disable (down).

Figure 5. MNS exciter RF enable S2 switch location in disable (down)
Plug the power supply on the dummy load into a 110 VAC service outlet in the PGR cabinet.
Use a digital multimeter to measure resistance between dummy load RF connector center pin and shield. Confirm a reading of 50 ohm +/- 5 ohm.

Replace the dummy load if the resistance is out of range.
Remove the transmission cable from RF OUT.
- (For AMT amplifier) Remove cable from J4 .
- (For For the original CPC amplifier, part number 5411744) Remove cable from J3 .
- (For For the new CPC amplifier, part number 5750811) Remove cable from J2 .
Connect directly to the 35 kW 3.0T RF dummy load. Plug the power supply into the dummy load and the power supply into the 100 VAC service outlet in the cabinet.

Figure 6. Setup for MNS output measurement

Figure 7. Coupler attached to original CPC amplifier (J3)

Figure 8. Coupler attached to J2 on power amplifier
Place the RF ENABLE S2 switch on the exciter in the enable (up) position.

Topic ID: id_SL1761403-1046254

Setting up software tool to calibrate UPM - MNS forward power

About this task

Note: (For PET/MR systems) Remove the CMA coil and replace it with the CMA proxy. MNS will not operate with the CMA coil.

This procedure applies to both the AMT and CPC amplifiers.

Procedure

Attach the MNS 31P TR switch cabling to the LPCA A connector.

Figure 9. MNS 31P TR switch connection to LPCA (MR750 system shown)
Move the cradle to the Home position and then drive it into the bore.
Press Landmark when the alignment light is approximately where the center of the head coil would be.
Start the UPM tool:
1. (For non-proprietary Service Tools) From the Common Service Desktop, select Calibration > UPM Tool > Click here to start this tool .
The UPM tool window appears.
Figure 10. UPM tool
Make the following selections for the settings:

Table 2. Settings for MNS RF chain
Setting Value
Nuclei 31P
Task Calibrate UPM
RF Chain MNS
Power Type Forward
Select Start , verify that the hardware setup is correct, and select Yes .
After approximately one minute, you are asked to confirm the peak power value output from the amplifier. The peak power should be within the limits specified in 8 kW 3.0T MNS Amplifier Calibration . If the power read from the power meter is within these limits, click Yes . Otherwise, click No and recheck calibration of the RF amplifier.
The window displays the current step in progress, and indicates Pass/Fail when complete.
1. If a failure occurs, see UPM failure .
2. If no power is output from the MNS amplifier during UPM forward power calibration:
  1. Close the UPM tool and start a new exam in geservice mode with a patient weight of 50 kg.
  2. Create a landmark with the 31P TR switch
  3. Select Service > MNS Setup , and then prescribe the 31P Func Check series.
  4. Save and download the sequence with any acceptable scan parameters.
  5. Open Spectro Prescan, select Start , and let the sequence run for about 10 seconds.
  6. Stop the sequence, end the exam, and continue with the UPM calibration.
Proceed to MNS reflected power calibration .

Table 2. Settings for MNS RF chain
Setting	Value
Nuclei	31P
Task	Calibrate UPM
RF Chain	MNS
Power Type	Forward

Topic ID: id_SL1761419-1046254

MNS reflected power calibration

Procedure

Move the RF Enable S2 switch to the disable (down) position.
(For AMT amplifier) Disconnect the cable from MNS output J4 at the rear of the amplifier and leave J4 open.
(For CPC amplifier) Disconnect the RF output cable:
- (For For the original CPC amplifier, part number 5411744) Open the rear door and disconnect the RF output cable from J3 of the combiner module in the CPC cabinet and leave open.
- (For For the new CPC amplifier, part number 5750811) Open the rear door and disconnect the RF output cable from J2 of the power output in the CPC cabinet and leave open.
Move the RF Enable S2 switch to enable (up) position.
Return to the UPM Tool window.
Make sure Nuclei is set to 3IP .
Set Power Monitor to Reflected .
Select Start .
In a few minutes, the tool displays Pass/Fail. If failure occurs, see UPM failure . If Pass is displayed, perform the functional check procedure for the applicable RF output, as follows:
1. Disable the RF Enable S2 switch by moving it to the DOWN position.
2. Reconnect the RF dummy load to RF output connector on the back of the MNS amplifier.
3. Enable the RF Enable S2 switch by moving it to the UP position.
4. Return to the UPM tool window.
5. Set Task to UPM Functional Check and click Start to complete the UPM functional check.

Topic ID: id_SL1761427-1046254

UPM failure

Procedure

Ensure proper setup of the calibration equipment.
Check the cabling between the UPM and the amplifier.
Check mgd_stage file: cd /w/config . Remove the “ p ” if necessary (p=UPM emulated).
(For AMT amplifier) Refer to Re-enable VSWR fault detection in AMT amplifier ONLY and perform steps to safely reconnect J7 and J8 cables to the controller module PCB.
Do the maximum RF power calibration procedure. Repeat the UPM calibration.
Check the UPM for power.
Check the error log for details of the UPM failure.
Do body UPM calibration. If it fails, check the error log.
If detector boards are replaced, do the UPM calibration to put the new boards into service.

Topic ID: id_SL2671477-1046254

Re-enable VSWR fault detection in AMT amplifier ONLY

Procedure

Apply LOTO on the RF amplifier and PEN cabinet to remove power to the MNS amplifier. See the MR Service Safety Manual , PN 5452735.
Remove the top panel of the MNS amplifier cabinet (see Figure 1 ).
Reconnect the SMA cable connections to J7 and J8 on the controller module PCB (see Figure 3 ).
Replace the top cover of the controller module in the MNS amplifier cabinet (see Figure 2 ).
Replace the top panel of the MNS amplifier cabinet.
Remove LOTO (see the MR Service Safety Manual , PN 5452735) and reapply power to the MNS amplifier.

Topic ID: id_15011850

Finalization

Procedure

If you have not run the UPM MNS functional check during this procedure, run UPM - MNS Functional Check .
In the UPM Tool, select Quit .
Set RF Enable S2 to disable (down) on the exciter Figure 5 .
Remove the cables and power measurement equipment from the MNS amplifier.
Reattach the RF OUT cable at the rear of the cabinet.
Set SW2 to TR Enable (up) on the driver module.
Set RF Enable S2 to Enable (up) on the exciter.