Olympus BH-2 BHTU Посібник - Сторінка 2

Переглянути онлайн або завантажити pdf Посібник для Мікроскоп Olympus BH-2 BHTU. Olympus BH-2 BHTU 24 сторінки. Sliding focus block
Також для Olympus BH-2 BHTU: Повний демонтаж, очищення та повторний монтаж (23 сторінок)

Introduction

This document provides a detailed description of the electrical circuitry of the 100/115V version of the Olympus BHT and

BHTU microscopes, which are part of the BH‐2 family. The information contain herein is intended to supplement the

information published in the Olympus Research Microscope Series BH2 (BHS) Repair Manual, by providing additional

circuit details and a complete theory of operation, as well as correcting errors that were found in the circuit diagram

published by Olympus. This information was obtained by performing tear‐down inspections of functional BHTU

microscopes configured for 100/115V operation.

Safety Warnings and Disclaimers

The content of this document is provided for informational purposes only, with no expressed or implied warranties

whatsoever, including, but not limited to, function, suitability, safety, accuracy, and completeness of information.

Repairing your own microscope may seem like a hip and cool thing to do that will make you the envy of all of your

friends, but being dead will not. Potentially lethal voltages are present inside these microscopes. Do not attempt

repairs or troubleshooting if you lack the necessary skills, training, and confidence to safely perform repairs on line‐

powered electrical equipment. If you choose to attempt repairs or troubleshooting, do so at your own risk.

Overview of Electrical Circuitry

The electrical circuitry of the Olympus BHT/BHTU microscopes resides completely within the base of the microscope

stand. AC power is provided by an AC inlet jack on the back, where the line cord connects. There is a power switch on

the front to turn the illumination on and off, as well as an intensity control on the right‐hand side to vary the lamp

voltage. There is a voltage selector switch on the bottom of the base to allow operation under normal or low‐line

conditions, and enclosed within the base are a power transformer, a bridge rectifier, a main printed circuit board, and a

power transistor. A 6V/20W halogen lamp resides in the lamp house on the rear of the stand. Later stands have a light

preset switch and a screwdriver‐adjustable light preset control, located just above the intensity slider, to provide preset

lighting intensity for photographic applications.

The BHT/BHTU electronics performs two independent, yet related functions, in response to a variable control signal

from the intensity potentiometer. The first function is intensity control of the halogen lamp. To provide this, the

dimmer circuitry varies the voltage applied to the lamp in response to this control signal. The second function is display

of the lamp voltage via a four‐segment LED bar‐graph display, which also operates off of the intensity control signal.

Details of both of these circuit functions are described in the sections below.

Lamp Dimmer Circuitry

Figure 1 is a simplified schematic diagram of the lamp dimmer circuitry. This diagram contains the details necessary for

an understanding of the basic operation of the lamp dimmer. Unnecessary details such as such as switching, fusing,

electrical interconnects, and current limiting have been omitted for clarity. Refer to Appendix 2 and Appendix 3 of this

document for complete and detailed schematic diagrams of the BHT/BHTU electronics.

Figure 1 – BHT/BHTU Lamp Dimmer Circuitry (without Current Limiting)

Olympus BH‐2 (BHT/BHTU) Electronics

Revision 2

Page 2 of 24