Olympus BHTU Полная разборка, очистка и сборка - Страница 5

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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 BHSU or BHTU version of these microscopes

is that the grease in the reverse 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

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 reverse

nosepiece assembly on a BHTU 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 apply to the

reverse nosepiece assembly used on the Olympus BHSU

and BHTU microscope stands.

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

BHSU/BHTU reverse nosepiece assembly.

• Center punch or nailset tool

Complete Teardown, Cleaning, and Reassembly of the Olympus BHSU/BHTU Reverse Nosepiece Assembly

been

periodically

lubricated

• Electric heat gun (item 1 of

• Lens-spanner tool (item 6 of

• Screwdriver set, JIS (item 2 of

• Soft-jaw pliers (item 5 of

A Few Words About JIS Screws

Screws with JIS heads are frequently found in much of

the 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

BHSU/BHTU reverse nosepiece assembly.

• Cleaning solvent (see recommendations below)

• Lubricant (see recommendations below)

• Silicone RTV adhesive, black (item 7 of

Recommended Lubricant Types

Plastilube® Brake Grease or Mobilgrease 28 (item 8 of

Appendix

1) are recommended for use in the reverse

nosepiece assembly. Both Plastilube® Brake Grease and

Mobilgrease 28 are medium-consistency greases which

will remain stable and serviceable for many years to

come.

Recommended Solvents

Some type of cleaning solvent will be needed to remove

the old grease from the various components of the

BHSU/BHTU reverse nosepiece assembly. Solvents that

can be used are acetone (commonly sold as fingernail

Appendix

Figure

1).

Appendix

Revision 3

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