Complete Teardown, Cleaning, and Reassembly of the Olympus BH2-5RE Modular Revolving Nosepiece
Page 5 of 18
Revision 3
Introduction
The microscopes in the Olympus BH-2 line have largely
been replaced in the professional and clinical world,
due to their advancing age and the lack of repair parts
from Olympus. A great many of these microscopes
were produced in their day, and because of this they
are readily available on the used market for very
reasonable prices. Thanks to their excellent build
quality and solid optical performance, these scopes are
now very popular with hobbyists, providing an
affordable, high-quality alternative to the Chinese-made
scopes prevalent today.
One issue that might be encountered when purchasing
either the BHS or BHT version of these microscopes is
that the grease in the BH2-5RE modular revolving
nosepiece assembly may be dried and gummy, resulting
in a stiff or gritty feel of the revolving nosepiece.
Another issue that may be encountered is with the
mechanical detents in the revolving nosepiece. After
many years of hard service, especially if the nosepiece
assembly has not been periodically lubricated
throughout its life, one or more of the detent stops may
be worn to the point where the detents are sloppy, and
the affected objectives do not maintain proper radial
indexing. At best, this is annoying to the operator, and
at worst can render the revolving nosepiece unusable.
This document describes the complete teardown,
cleaning, lubrication, and reassembly of the BH2-5RE
(five-position) modular revolving nosepiece assembly as
used on a BHS or BHT microscope stand. Completion of
this maintenance procedure should restore the proper
feel to the nosepiece turret. Additionally, this
maintenance should reduce further wear of the
mechanical detent stops. Note that if the detents stops
are already excessively worn, there is no repair for this
other than the replacement of the revolving turret.
Scope of this Document
The procedures detailed in this document directly apply
to the BH2-5RE (five-position) revolving modular
nosepiece assembly used on the Olympus BHS, BHSP,
BHT, and BHTP microscope stands. This procedure is
also applicable the BH2-6RE (six-position) modular
revolving nosepiece assembly, due to its similarity with
the five-position nosepiece, although a separate
document exists in this series detailing the BH2-6RE.
Note that the original Olympus service literature did not
address the teardown and repair of the various
revolving nosepiece assemblies used on BH-2 stands, as
these were field-replaceable assemblies that were
considered unserviceable by Olympus.
Tools Needed
The following tools will be needed to complete the
teardown, cleaning, lubrication, and reassembly of the
BH2-5RE modular revolving nosepiece assembly.
•
Center punch or nailset tool
•
•
Lens-spanner tool (item T3 of
•
Screwdriver set, JIS (item T2 of
A Few Words about JIS Screws
Screws with JIS heads are frequently found in much of
the older equipment designed and manufactured in
Japan. JIS screws look very much like standard Phillips
screws, but they differ in that JIS screws were designed
to not cam-out under torque, whereas Phillips screws
were designed to intentionally cam-out, as a means to
limit the torque applied to the fasteners. Because of
this crucial difference in the geometry of the two driver
types, JIS screws will be damaged by standard Phillips
drivers if too much torque is applied. JIS screws can
usually be identified by the presence of a single dot, or
by an “X”, stamped into one of the four quadrants of
the cross-point depression (see
Figure 1
–
A typical JIS Screw
Supplies Needed
The following supplies will be needed to complete the
teardown, cleaning, lubrication, and reassembly of the
BH2-5RE modular revolving nosepiece assembly.
•
Cleaning solvent (see recommendations below)
•
Lubricant (see recommendations below)
•
Recommended Lubricant Types
Plastilube® Brake Grease or Mobilgrease28® grease
(item S2 of
) are recommended for use in
the BH2-5RE modular revolving nosepiece assembly.
Both Plastilube® Brake Grease and Mobilgrease28® are
medium-consistency greases which will remain stable
and serviceable for many years to come.
