Discovery MR750w and SIGNA™ Architect T 3.0T System Service Methods
5690002-2EN Revision 4
Object ID: 00000018WIA307EBE20GYZ
Topic ID: id_13106530 Version: 3.9
Date: Feb 4, 2021 7:51:05 PM

Body Coil Tuning (Network Analyzer Kit 5336593-3 or Later)

Prerequisites

Table 1. Personnel requirements
Required persons	Preliminary requirements	Procedure	Finalization
	Not Applicable	Not Applicable	Not Applicable

Table 2. Tools and test equipment
Item	Quantity	Effectivity	Part number	Manufacturer
Network Analyzer Service Tool Kit	1	-	5336593-3 or 5336593-4	-
Body Loader with Sphere Phantom	1	-	2371511	-

Table 3. Safety

DANGER

Strong Magnetic Field!

Ferrous materials can become dangerous projectiles in the presence of the magnetic field Produced by the Magnet.

Do not Bring any ferromagnetic tools or equipment into the magnet room.

Notice

System must be in scanning condition with system air and water cooling in proper operation for a minimum of 15 minutes.

Notice

RF body coil temperature must be stable.

Table 4. Required conditions
Condition	Reference	Effectivity
Body Coil Centering must be done.	-	-
Cradle is not located in the magnet bore.	-	-
Bridge is installed in magnet bore.	-	-
Phantom is set-up correctly (System Pre-setup for Tuning).	-	-
Cables are connected correctly (Tuning Cable Connection (Equipment Setup)).	-	-
Driver module DD Bias is in Body Mode (-13.6 VDC unloaded, ~2.6 VDC loaded; exact voltages are not critical).	-	-
Body Coil Temperature matches magnet room temperature (HEC air flow — ON) for a minimum of 15 minutes.	-	-

About this task

This procedure is for network analyzer kit 5336593-3 or later.

Body coil tuning is performed by adjusting variable capacitors (VC1, VC2, VC3) to tune f1, f2, f3, and MagS21 according to the network analyzer screen. If it is difficult to adjust parameters by variable capacitors, replacement of dielectric material might be required (also according to the network analyzer screen).

Table 5. Body Coil Tuning Steps
STEP	PROCEDURE	SECTION
1	Start
2	System Pre-setup for Tuning	System Pre-setup for Tuning
3	Calibration of Network Analyzer	Calibration of Network Analyzer
4	Tuning Cable Connection (Equipment Setup)	Tuning Cable Connection (Equipment Setup)
5	Perform Body Coil Tuning per Network Analyzer Navigation	Body Coil Tuning using Network Analyzer Navigation, Further Adjustment, Troubleshooting
6	Finalization	Step 1

Topic ID: id_SL15524841-1158723

System Pre-setup for Tuning

Procedure

Note: The following process must be used to tune the coil to specification. However, if the current tuning values of a particular coil are wanted, the original macro can be utilized. The original macro is found in Body Coil Tuning (Network Analyzer Kit 5336593-2).
Perform the following sub-steps to prepare a body coil scan on the scan window to set up driver module body bias mode.
1. On the exciter/ref clock module located in the PEN cabinet, set the RF Enb switch to down (Disable).
  
  Figure 1. Exciter/Ref Clock Module
2. Dock the patient table.
3. At the magnet control panel, press the In button to advance the cradle into the bore until the enclosure display indicates 800 mm.
4. At the magnet control panel, press Alignment Light. Then, press Landmark and Advance to Scan to advance the empty cradle to the magnet isocenter.
5. At the operator console, set up any body coil scan on the scan window to set up the driver module bias mode. The following steps are an example of body coil scan setup:
  1. Click New Patient.
  2. Enter geservice for Patient ID and 111 for Weight. Then, click Start Exam.
  3. In the Protocol Selector, select Service from Protocol Library. Select snr_check and SNR Body Axial, FuncChk:Sys. Then, click > (right arrow). The protocol is transferred to the right field (Multi Protocol Basket).
  4. Click Accept for Protocol Selector.
  5. Click Save Rx to download body coil scan parameters.
  6. Click Scan and select Manual Prescan from the menu.
  7. Allow the scanner to pulse once, then select Done in the Manual Prescan window.
    
    The driver module should now be supplying correct DC bias for tuning the body coil (-13.6VDC).
  8. From the pull down menu on the scan window (End/End Exam), select End Exam.
6. Use the emergency release latch on the cradle to unlatch the cradle from the LPCA, and then pull the cradle back onto the patient table to the Home position.
7. At the magnet control panel, press the In button to drive the LPCA out of the magnet bore to the end of the rear bridge.
8. Undock the patient table and place it to the side.
Remove the bridge cover, right center cover, and right rear cover.

Figure 2. Remove Covers
Place body loader with phantom on the bridge and push it to the magnet center so that the front edge of body loader is 835 mm (33 inches) away from the front edge of the bridge. The loader and phantom assembly will sit on the belt path notch and are centered left-to-right on the bridge.

Figure 3. Body Loader Setup

Topic ID: id_SL3911426-1158723

Calibration of Network Analyzer

Procedure

CAUTION

Electric Hazard!

Make sure that the DC cable is not connected to the bias T, as damage to the bias T can result .

Connect the bias T at Port 1 and Port 2. Do not connect the bias cable at this time.

Notice

Use an AC wall outlet. Do not use the AC outlet at the PGR cabinet. The PGR cabinet may be shut down during the procedure, but the network analyzer power must remain ON throughout body coil tuning to keep activating calculated data in the macro.

Note:

It is recommended that you connect a mouse to one of the USB ports on the network analyzer.

If not using the mouse, use the hard keys. For example, select the Menu hardkey and then use the arrow <> hardkeys to navigate and highlight, and the ENTER hardkey to select from menu.

Power ON the network analyzer. If no power is seen, confirm that the AC power switch on the rear of the unit is in the 'I' position.

If the network analyzer is not ready, start either the ZVL Analyzer (5336593-3) from the Windows screen, or the Vector Network Analyzer (5336593-4). (This step might not be needed.)

Figure 6. Start ZVL Analyzer (5336593-3)

Figure 7. Start Vector Network Analyzer (5336593-4)
For Vector Network Analyzer (5336593-4), do the following to change the Preset mode to Network Analyzer:
1. Press Setup.
2. Click System Config.
3. Click VNA.
4. Close the window.

Select 750w body coil tuning, based on network analyzer:

Option	Description
For ZVL Analyzer (5336593-3)	Select Nwa-Setup > External Tools > 750w Body Coil Tuning.lnk. Figure 8. 750w Body Coil Tuning.lnk
For Vector Network Analyzer (5336593-4)	Select the Start menu, and then select 750w Body Coil Service Tuning. Figure 9. 750w Body Coil Service Tuning

The following screen displays. For button selection, proceed to Step 7.

Figure 10. Calibration Start Menu
Select the correct button as follows:
1. If calibration of network analyzer has not been done yet, click OK to start calibration. Then, go to Step 8.
2. If calibration of network analyzer has been done using the same macro, click Skip to skip the calibration and go to equipment setup.
  1. If Skip is clicked, the confirmation screen shown in Figure 11 displays. Confirm the condition again and click OK. Then, go to Tuning Cable Connection (Equipment Setup).
    
    Figure 11. Confirmation Screen
  2. If any condition is not satisfied, click Quit, then press blue Pre-Set hardkey button on the front left of unit, and start the tool again.
When OK is selected at Step 7, the following message displays. Confirm that the DC cable is not connected to bias T and click OK.

Figure 12. Message
Connect N(m) to N(m) coaxial cable to bias T of Port 1.

Figure 13. Cable Connection 1

Note:
Do not touch cable ends, and minimize human interaction during network analyzer calibration, because this can change the impedance of the calibration setup.

Also it is best to not cross the cables, and route them so that they are parallel and separated from each other as much as possible.

Note: It is recommended that the 50 ohm load (Match Standard) be measured with a DVM to confirm that it is operational (50 ohms +/- 5 ohms). Connecting it to the end of BNC-f to BNC-f adapter or BNC-f to N-m adapter and measuring through opposite end of adapter sometimes provides the most reliable electrical connection for measurement.
Connect N female barrel and “BNC female to N male” to the end port 1 of the channel 1 cable. Do not attach any BNC standard connectors. Click OK when the following message is displayed. Do not make any changes until prompted.

Figure 14. N Female Barrel and Male N to BNC Female

Figure 15. Message for Open

Note: It will take about 15 seconds to display next message after clicking OK.
Connect Short standard to “BNC female to N male” and click OK when the following message is displayed.

Figure 16. Message for Short
Remove Short, connect 50 Ohm load standard and click OK when the following message is displayed.

Figure 17. Message for Match Standard (50 Ohm Load)
Using a second set of unused hardware, repeat Step 9 through Step 12 for port 2.
Connect port 1 and port 2 cables through female barrel.

Figure 18. Cable Connection 2
Click OK when the following message is displayed. Calibration is complete.

Figure 19. Message for Through Standard
After calibration is complete, the following screen displays. Proceed to Tuning Cable Connection (Equipment Setup). Keep the network analyzer screen as it is.

Figure 20. Message for Equipment Setup

Topic ID: id_SL5108032-1158723

Tuning Cable Connection (Equipment Setup)

Procedure

Warning

Strong Magnetic Field!

network analyzer must remain outside magnet room at all times.

Never TAKE network analyzer in magnet room.

Remove cables from the DTRS switch for J2, J7, J8, and J3.

Connect the removed cables through the extension cables to the network analyzer as described in the table below.


Cable removed from TR switch	Extension Cable	Connector	Body Coil/Bias Cable
J2	N(M)	N(M)	Body coil 1 cable
J7	MHV(F)	BNC(M)	Bias cable from driver module
J8	MHV(F)	BNC(M)	Bias cable from driver module
J3	N(M)	N(M)	Body coil 2 cable

At the network analyzer, complete the following connections:
1. Prior to connecting bias cables from J7 and J8 to the bias T ports, check for proper voltage going to the bias T ports. Voltage should be approximately –13.6 VDC.
2. Connect body coil 1 cable to port 1 Bias T.
3. Connect body coil 2 cable to port 2 Bias T.

Topic ID: id_SL3911454-1158723

Body Coil Tuning using Network Analyzer Navigation

Procedure

Note: Before performing this procedure, all Required Conditions must be met.
After the tuning cable connection (equipment setup) is completed, click OK.

Figure 22. Message for Equipment Setup

Ch1 measurement will start. Click OK to record f1.

Note:

If the following screen displays, it means S11 magnitude is unusual.

Figure 24. Message for Unusual S11 Magnitude

In this case, check the following conditions:

Cradle is not located in magnet bore.
Bridge is installed in magnet.
Phantom is set up correctly as described in System Pre-setup for Tuning.
Cables are connected correctly as described in Tuning Cable Connection (Equipment Setup).

Driver module DD bias in body mode (-13.6 VDC unloaded, ~2.6 VDC loaded; exact voltages are not critical).

Notice

If DD bias is in head mode, the voltage is ~145 VDC (unloaded). If you need to measure DD bias voltage, be careful not to create an electrical short between center conductor (-) and outer collar (+) of the connector so you do not damage any equipment.

After the problem is corrected, click Retry.

Ch2 measurement will start. Click OK to record f2.

Note:

If the following screen displays, it means the S22 magnitude is unusual.

Figure 26. Message for Unusual S22 Magnitude

In this case, check the following conditions:

Cradle is not located in magnet bore.
Bridge is installed in magnet.
Phantom is set up correctly as described in System Pre-setup for Tuning.
Cables are connected correctly as described in Tuning Cable Connection (Equipment Setup).

Driver module DD bias in body mode (-13.6 VDC unloaded, ~2.6 VDC loaded; exact voltages are not critical).

Notice

After the problem is corrected, click Retry.

From this point on, the display of the network analyzer will guide the operation. Follow the instructions shown.

Note:

If the body coil is within specification, a pop-up (shown in Figure 34) displays, which means you are done tuning.

If VC1 CW or VC1 CCW is shown, turn VC1 using stick to tune f1 until VC1 TUNED! is displayed. After VC1 TUNED! is displayed, click OK to go to the next step.

ITEM	DESCRIPTION
1	VC1 location
2	VC2 Location
3	VC3 location
4	Body coil front view
5	Variable capacitor location

Note: The macro will dictate which capacitor should be tuned first, second, then third.

Note:

If VC1 reached the CW or CCW limit, click the appropriate button to go to the next step.

If VC2 CW or VC2 CCW is shown, turn VC2 using stick to tune f2 until VC2 TUNED! is displayed. After VC2 TUNED! is displayed, click OK to go to the next step.

Figure 29. VC2 Display

Note:
If VC2 reached the CW or CCW limit, click the appropriate button to go to the next step.

If VC3 CW or VC3 CCW is shown, turn VC3 using stick to tune f3 until VC3 TUNED! is displayed. After VC3 TUNED! is displayed, click OK to go to the next step.

Note:

If VC3 reached the CW or CCW limit, click the appropriate button to go to the next step.

Note:

If the following screen displays, it means S11, S22, or S21 magnitude is unusual.

Figure 31. Message for Unusual S11, S22, or S21 Magnitude

In this case, check the following conditions:

Cradle is not located in magnet bore.
Bridge is installed in magnet.
Phantom is set up correctly as described in System Pre-setup for Tuning.
Cables are connected correctly as described in Tuning Cable Connection (Equipment Setup).

Driver module DD bias in body mode (-13.6 VDC unloaded, ~2.6 VDC loaded; exact voltages are not critical).

Notice

After the problem is corrected, click Retry.

If the following screen is displayed, do not edit or continue procedure until the coil is removed. It will be necessary to remove the coil, determine the dielectric material configuration, and change the dielectric material before proceding. Go to Further Adjustment.

Notice

The System HART ID for the body coil does contain the Dielectric Material Configuration. This information is used during the manufacturing process only. Therefore, since it is possible that Dielectric Material Configuration will need to be changed during the tuning process during installation or during FRU replacement, it is recommended to ignore this value.

Figure 32. Message for Dielectric Material Adjustment

When the following screen displays, click OK to start the calculation.

Figure 33. Record Data Screen

Measured data is calculated and the result is shown on the display. Proceed as described below.

Note:

The measured data is archived in the following directory of network analyzer:

C:\Program\750w Body Coil Tuning Macro
File name example: September 19, 2012 @ 5_35 PM Data.txt

Select Firmware Exit, My Computer to save to USB memory stick.

Notice

It is recommended that you save measured data after all data are in PASS condition. If you want to save measured data to USB memory stick under FAIL condition, you must exit firmware and the network analyzer navigation will stop. In this case, you need to restart ZVL analyzer and you need to perform extra steps for tuning.

When the screen below is displayed, body coil tuning is completed. Go to Step 1.

If any of the results fail, the screen below displays. Click OK and follow the navigation screen to perform more tuning.

Figure 35. Measured Data (Failed)

Topic ID: id_SL4908613-1158723

Further Adjustment

About this task

This procedure is required if the following screen displays.

Procedure

Notice

Do NOT turn off network analyzer throughout body coil tuning, to keep activating calculated data in macro.

Notice

Lockout/tagout (LOTO) for PGR PDU/gradient subsystem must be performed before body coil removal, as described in RF Body Coil Replacement.

Remove body loader with phantom from bridge.

Remove body coil. See RF Body Coil Replacement .
Check the site’s body coil condition.

Figure 37. Dielectric Material Configuration Check

ITEM DESCRIPTION
1 Body coil removed
2 Dielectric material
3 Rear or service end
4 Front or patient end

Note: If there is no body coil FRU case available, place the body coil on two pads, making sure to protect the drive cables of the body coil from damage. Make sure the body coil does not roll over.
Inspect location of each piece of dielectric material on the coil and confirm that the location of all material exactly matches 1 of 4 configurations shown in Figure 37 before continuing. Any errors must be corrected and measurements in Body Coil Tuning using Network Analyzer Navigation performed again.
From the menu, select the option corresponding to the site configuration and click OK.

Figure 38. Select from Menu
Change dielectric material according to the message.

Figure 39. Change Dielectric Material

Note: The body coil FRU includes dielectric materials for adjustment, so no kit needs to be ordered. If dielectric material is required after XRMw replacement, order Dielectric Material FRU Kit (5423650).

Note:
When replacing dielectric material to Standard x 8 pieces or Standard x 8 pieces + Lower Shift x8 pieces, the order is important. Follow the illustration below.

Figure 40. Dielectric Material Order

ITEM	DESCRIPTION
1	Body coil removed
2	Dielectric material
3	Rear or service end
4	Front or patient end

Notice

Before each body coil installation, inspect airflow gaskets (5404530 and 5404530-2). Gaskets should be bonded along entire length.

After changing the dielectric material, install the body coil by reversing the removal. See RF Body Coil Replacement.

Make sure LOTO is removed and TPS reset is performed.

Notice

Because body bias mode was removed due to LOTO of PGR cabinet, it is necessary to set driver module to body bias mode.

Perform the following steps to set driver module to body bias mode:

Perform System Pre-setup for Tuning.
Confirm that the cable is connected as described in Tuning Cable Connection (Equipment Setup).

When the body coil temperature is stable (usually 15 minutes after successful TPS Reset and HEC chilled air blowing over coil) click OK on the dialog box of the network analyzer. It will navigate to the next step.

Topic ID: id_SL4908620-1158723

Troubleshooting

Procedure

If the following screen is shown, perform body coil troubleshooting.

Perform Body Coil Centering.
Confirm bridge alignment and height are correct as described in the installation manual.
Check phantom position.
Replace the body coil.

Topic ID: id_14939173

Finalization

Procedure

Record final values.

Table 6. Final Value
Parameter	Final Value	Specification
f1	MHz	127.75 to 128.05 MHz
f2	MHz	127.75 to 128.05 MHz
\|f1 - f2\|	MHz	50 KHz
\|f3–(f1 + f2)/2\|	MHz	50 KHz
S21	dB	-20dB

Restore cables, phantom, and enclosure.
On the exciter/ref clock module in the PEN cabinet, set the RF Enb switch to up (Enable).

Figure 42. Exciter/Ref Clock Module
Run TR Dynamic Disable Calibration.
Run System gain calibration.
Run DD Quadrature Calibration .
Run Doing the Echo Planar Test.
Perform a quick head and body scan to ensure the system is functioning properly.