Arrowhead – 2H Signal
Customer reported that they could not lock (using 2H) or gradient shim. Looked at 2H RF path and good signal coming out of console to probe. Problem must be on receive side. Swapped the following parts for troubleshooting:
- 2H Diplexer
- Lock Preamp
- 2H RF Relay (verified operation)
- 2H Filter (bypassed)
Believe issue is the Mixer Module (PN 0191422700)
Swapped mixer module and problem still persisted. Looked at LO coming into mixer module and found it was the correct frequency and amplitude but when below 80 MHz, it was not stable. When looking at it with a frequency counter, the frequency shifted about 1 KHz. When looking at frequencies about 80 Mhz, the signal was steady. Traced the instability back to the RF coming out of the Synth Board output.
Synth Board is not available in OTI or NMRA stock. Customer will need to order directly from Agilent.