Sample Insert (down) Problems
NMR Case
Trouble Shooting Guide
BRUKER
Page 5 of 15
1.8
Interface tube inside the adapter collar
Inside the adapter collar is a tube, which interfaces the adapter collar with the BST shim upper stack (see Figure 2 and 3 at
the end of this manual and Figure 3 at the end of the installation manual). The correct seating of the adapter collar and the
interface tube is critical for the reliability of the sample changer.
To check the seating, first remove the 3 screws and then remove the NMR Case base plate, leaving only the collar in place.
Check that the bottom of the collar is flush with the BST. Check that the interface tube is flush with the top of the collar.
Check that the five fingers of the interface tube are not bent inwards and block the inside diameter of the BST.
See figure 4 at the end of the installation manual for the correct seating. See figure 5 at the end of the installation manual for
the incorrect seating.
If the collar cannot be seated correctly, then check the BST top head for parts sticking out (labels or covers).
If the O-ring does not engage onto the BST (it feels too tight), then apply some silicone grease onto the O-ring inside the
collar.
If the interface tube is not flush with the top of the collar, then it may be an old version (made from brown plastic). Replace it
with a new version made from black metal (Part number B3695).
If the inner diameter of the interface tube seems to be too small, then it may be an old version (made from brown plastic).
Replace it with a new version made from black aluminum metal (Part number B3695).
2. Sample Insert (down) Problems
2.1
NMR Case or magnet not level
The shim stack must be vertical and the NMR Case horizontal aligned. Check it with the circular level (supplied with the tool
kit). The bubble must be inside the innermost ring. Adjust the magnet stand and the telescopic front feet as necessary.
2.2
BST shim stack with sharp edges
On top of the BST, where the samples are inserted, there are some cutouts located on the inside diameter. Some cutouts have
sharp edges. If this is the case (check it with a finger), either replace the BST or remove the sharp edges with a file.
2.3
Sample lift air bypass
After changing a sample, the new sample should stays on top of the sample holder tray for a short moment, before it is
rapidly inserted into the BST (within 2 seconds).
There is a small pneumatic cylinder located inside aluminum housing underneath the NMR Case base plate (see Figure 2 and
Figure 3). This cylinder opens and closes a sample lift air bypass exit hole, located in the adapter collar. Check for the correct
opening and closing of this bypass exit hole.
If the bypass exit hole is not open completely, the sample does not get inserted fast enough into the BST and may get stuck
on top of the BST.
If the bypass exit hole is not closed completely, the sample will not eject to the top of the sample tray, but will sit on top of
the BST instead.
