Agilent Technologies 85110L User's And Service Manual page 63

Test Set Troubleshooting
Replacement Procedures
Center conductor pin and bead assembly removal
1. Use the collet extractor (supplied in the 7-mm cal kit box) to remove the collet.
2. Removing the outer nut assembly.
a. Rotate the outer nut counter-clockwise so the threaded sleeve retracts as far as
possible.
b. Use the 1/2 inch torque wrench (narrow width) on the gold wrench flats to carefully
remove the outer nut assembly. The pin and bead assembly may come out when the
nut assembly comes off.
3. Carefully remove the pin and bead assembly by pulling it straight out.
The pin and bead assembly should be inspected for any nicks, bent assembly, or other
defects that might degrade performance. Replace the whole pin and bead assembly if you
find any performance degrading defects.
Center conductor shimming procedure
Before using this procedure, you should measure and record the center conductor depth
with the collet removed, then use the center pin and bead assembly removal procedure
described earlier.
Determining the number of shims required. Each added shim reduces the center
conductor recession by approximately 0.001 inch (0.025 mm). If the center conductor (with
collet removed) is protruding, shims must be removed. If there are no shims in the
assembly, the whole center pin and bead assembly may need to be replaced. Reversing the
bead can sometimes bring a slightly out-of-tolerance assembly within tolerance.
Inserting or removing shims.
the pin assembly (the end that holds the collet).
1. Disassembling the pin and bead assembly. The assembly must be unscrewed to
install a shim(s). Special pliers, specified in
the pin that is held with a thread locking adhesive.
a. Grasp the pin and bead assembly as shown in
scratching the surface of the assembly. Some minor scratches may be unavoidable
and should cause no noticeable affect.
b. Note which side of the bead is facing the collet pin because the bead is not perfectly
symmetrical and should be replaced exactly as it was before disassembly.
c. Hold the short end stationary and unscrew the long end counterclockwise (these are
right-handed threads).
d. Loosen until you can unscrew it by hand. As you unscrew, note any shims that were
previously installed. They will be between the bead and the shorter pin.
2. Install or remove the shim(s) on/from the threaded end of the shorter pin.
3. Replace the bead on the threaded end and apply a small amount of a thread locking
adhesive (less than one drop) on the threads and remove any excess with a lint-free
cloth.
5-20
Shims are located between the bead and the short end of
Table 5-3 on page 5-12, are used to unscrew
Figure 5-7 on page 5-18. Try to avoid
Agilent 85110L Test Set