Olympus BH-NRE Посібник - Сторінка 4

Переглянути онлайн або завантажити pdf Посібник для Лабораторне обладнання Olympus BH-NRE. Olympus BH-NRE 17 сторінок. Modular revolving nosepiece

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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

one these microscopes is that the grease in the BH-NRE

modular revolving nosepiece assembly may be dried

and gummy, resulting in a stiff or gritty feel of the

revolving nosepiece.

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 (see

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 BH-NRE

(4-position) modular revolving nosepiece assembly as

may be found on a BH or BH-2 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

BH-NRE

4-position

revolving

assembly (with 25mm objective mounts to accept

Olympus short barrel NEO objectives) as used for

reflected darkfield illumination on Olympus BH and

occasionally BH-2 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 and BH-2

stands, as these were easily replaceable (i.e., modular)

assemblies that were considered unserviceable by

Olympus.

Complete Teardown, Cleaning, and Reassembly of the Olympus BH-NRE Modular Revolving Nosepiece

Another issue that may be

Appendix

modular

nosepiece

Tools Needed

The following tools will be needed to complete the

teardown, cleaning, lubrication, and reassembly of the

BH-NRE modular revolving nosepiece assembly.

•

Center punch or nailset tool

•

Electric heat gun (item T1 of

•

Screwdriver set, JIS (item T2 of

•

Lens spanner tool (item T3 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

1). At

Supplies Needed

The following supplies will be needed to complete the

teardown, cleaning, lubrication, and reassembly of the

BH-NRE modular revolving nosepiece assembly.

•

Cleaning solvent (see recommendations below)

•

Lubricant (see recommendations below)

Recommended Lubricant Type

Plastilube® Brake Grease or Mobilgrease28® grease

(item S1 of

the BH-NRE 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.

Appendix

Figure

Figure 1 – A typical JIS screw

Appendix

2) are recommended for use in

1).

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