Olympus BH-2 BHT - User Manual

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RevisionHistory
Revision Description Date
1 Initialrelease June17,2014
2
Correctederrorincircuittheory.Addedvendorinfo,lamp house
repairprocedure,andlightpresetcontrol/switchinformation.
March17,2016
 
 
Copyright©2014,2016CarlHunsinger
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part, for any commercial purpose without the express written consent of the author.
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includingthecopyrightnoticescontainedherein.Thisdocumentmaybefreelydistributed
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Olympus BH-2 BHT Specifications

General

Type	Biological Microscope
Focusing	Coaxial coarse and fine focusing knobs
Microscope Type	Upright
Observation Method	Brightfield, Phase contrast, Darkfield
Optical System	Infinity-corrected
Eyepieces	WHK 10x/20
Objectives	Achromatic, Plan Achromatic
Nosepiece	Quadruple or Quintuple revolving nosepiece
Stage	Mechanical stage with coaxial controls
Illumination	6V 30W halogen lamp
Condenser	Abbe condenser, phase contrast condenser
Diopter Adjustment	Yes (on at least one eyepiece)

Summary

Introduction

Safety Warnings and Disclaimers

Overview of Electrical Circuitry

Lamp Dimmer Circuitry

LED Bar-Graph Display Circuitry

Filtered DC Power Supply

Describes the filtered DC power supply for the comparator and LED circuits.

Comparator Thresholds and Control Signal

Explains comparator thresholds and control signal clamping for LED illumination.

Voltage Comparators

Details the operation of the quad operational amplifier as voltage comparators.

Power LED Indicator

Errors in Olympus Documentation

Bar-Graph LED Wiring Discrepancy

Details discrepancies in LED wiring from the original Olympus manual.

Control-Signal Clamp Wiring Discrepancy

Details discrepancies in the control-signal clamping network wiring.

Removing the Electrical Base from the Stand

Setting Up for Troubleshooting the Base

Safety Ground Connection for AC Inlet Jack

Common Problems with BHT;BHTU Electronics

Lamp House Contact Issues

Discusses issues with lamp house contacts and potential repairs.

Intensity Control Problems

Addresses erratic lamp intensity due to dust or oxidation in the control.

Obtaining Replacement Components

Power Transformer

Notes on power transformer failure and replacement challenges.

Bridge Rectifier

Lamp Intensity Control

Light Preset Board

Removing and Bypassing the Light Preset Board

Procedure for removing and electrically bypassing the light preset board.

AC Power Switch

Voltage Selector Switch

Main Board Replacement

Power Transistor Replacement

AC Inlet Jack Replacement

Lamp House Styles and Upgrades

Lamp House Repair Kit

Lamp House Repair Procedure

Halogen Lamp Specifications

Lamp Dimmer Waveforms

LED Bar-Graph Display Waveforms

Sources for Replacement Parts