Dear Lawrence,
Some possible possibilities are:
An RT shim has become disconnected. Check to see if they are connected. If so,
check the shim plug to see if a shim is open circuit or shorted.
There could be a fault in the shim power supply.
A cryoshim may have quenched. If so changing one low order RT shim should
improve the situation but to fix it, the chyoshim has to be reset.
The H0 (field) is disconnected. If so, adjusting the field will not move the
proton signal.
Godd luck fixing it.
Yours,
Roy Hoffman,
Hebrew University.
Received on Tue Jun 12 2001 - 09:18:24 MST