• Discovery MR750 3.0T System Service Methods
  • 5690009-2EN Revision 4
  • Object ID: 00000018WIA30B20450GYZ
  • Topic ID: id_2021402 Version: 3.1
  • Date: Nov 13, 2020 3:21:29 PM

Setting up hardware for UPM - MNS amplifier calibration or functional check

Sets up hardware for functional checks or calibration of forward power for the Universal Power Monitor (UPM) and Multi-Nuclear Spectroscopy (MNS) amplifier.

Procedure

  1. For functional checks, if measurement hardware is already connected from executing the procedure in Setting up and calibrating UPM - MNS, proceed directly to Doing UPM - MNS functional checks. Otherwise, proceed to the next step.
  2. Inhibit TR faults. Disable the driver module TR fault detection in the PEN cabinet. Make sure that switch SW2 is in the TR DISABLE position.
    Figure 1. Driver module front switches
  3. Set RF Enable S2 on the MNS exciter to Disable (down).
    Figure 2. MNS exciter RF enable S2 switch location in disable (down)
  4. Plug the power supply on the dummy load into a 110 VAC service outlet in the PGR cabinet.
  5. For hardware setup to calibrate amplifier forward power, use a digital multimeter to measure resistance between dummy load RF connector center pin and shield. Confirm a reading of 50Ω +/- 5Ω.

    Replace the dummy load if the resistance is out of range.

  6. Remove the transmission cable from RF OUT.
    • (For AMT amplifier) Remove cable from J4.
    • (For the GEN 1 CPC amplifier) (5411744) Remove cable from J3.
    • (For the GEN 2 CPC amplifier) (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 110 VAC service outlet in the cabinet.

    Figure 3. Setup for MNS output measurement
    Figure 4. Coupler attached to J3 on combiner
    Figure 5. Coupler attached to J2 on power amplifier
  7. Move the RF Enable S2 switch on the MNS exciter to the ENABLE (up) position.