background image

 

Olympus

 

BH

2

 

(BHT/BHTU)

 

Electronics

 

 

 

   

Revision

 

2

 

   

 

 

        

Page

 

20

 

of

 

24

 

LED

 

Bar

Graph

 

Display

 

Waveforms

 

 

 

Figure

 

25

 

 

Filtered

 

DC

 

Power

 

Supply

 

Line

 

at

 

Maximum

 

Lamp

 

Intensity

 

(100%

 

Setting

 

of

 

Intensity

 

Control)

 

 
 

 

Figure

 

26

 

 

Bar

Graph

 

Comparator

 

Threshold

 

Voltages

 

Summary of Contents for BH-2 BHT

Page 1: ...14 2016 Carl Hunsinger All rights reserved This document may not be reproduced or distributed in whole or in part for any commercial purpose without the express written consent of the author Permissio...

Page 2: ...t 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...

Page 3: ...ward biasing its base emitter junction and allowing it to increasingly conduct collector current Since the collector current of transistor Q201 is the base current of transistor Q101 Q101 in turn begi...

Page 4: ...setting of the intensity control and with an abnormally low lamp resistance of 0 2 LED Bar Graph Display Circuitry Figure 3 is a simplified schematic diagram of the LED bar graph display circuitry Thi...

Page 5: ...comparators were allowed to simultaneously drop to zero the comparators would be in an indeterminate state and depending on the input offset voltage parameters of the specific op amp devices their out...

Page 6: ...Olympus repair manual would not guarantee that the LEDs remain off around the zero crossings of the AC line Removing the Electrical Base from the Stand To gain access to the electronics in the base o...

Page 7: ...may be damaged if the stand is not placed on a suitable clutter free surface Store the stand someplace out of harm s way and where dust and debris will not accumulate on the exposed lighting component...

Page 8: ...exposed points within the electrical base Plug the AC line cord into a properly grounded AC receptacle The electronics may now be operated as necessary for troubleshooting purposes Never operate the m...

Page 9: ...r into the control so as to minimize overspray and blow back onto nearby components Be sure to allow the contact cleaner sufficient time to evaporate out of the control before re applying power to the...

Page 10: ...chassis to facilitate heat flow The NTE5322 is available from Allied Electronics and from Amazon Figure 8 Bridge Rectifier Mounted to BHT BHTU Electrical Base 100 115V Version Lamp Intensity Control T...

Page 11: ...trical base into an earlier stand that does not have the chassis notches to accommodate this board Removing and Bypassing the Light Preset Board Remove the light preset board from the electrical base...

Page 12: ...PDT slide switch rated for 4A 125VAC and 2A 250VAC The slide protrudes 3 8 from the mounting surface and the mounting holes are spaced 1 1 8 on center There are openings on both ends of this switch th...

Page 13: ...normal operation and because of this the solder joints can sometimes go bad Resoldering the leads of R201 may be enough to fix an inoperative lamp dimmer Resistor R201 can be replaced with a Vishay CP...

Page 14: ...parts listed above can be found look for an NPN part with a collector current rating of at least 15A a collector to emitter voltage rating of at least 100V and a current gain of at least 40 in a suit...

Page 15: ...by Olympus as part number 5 LB402 did not have a metal reflector behind the bulb Later in the life of the BHT BHTU Olympus upgraded the lamp house to the LS20H M2 part number 5 S119 which incorporated...

Page 16: ...a replacement for the back cover and a new G4 lamp socket may be used to overhaul either the LS20H or the LS20H M2 lamp houses The replacement back is provided since the original can be damaged durin...

Page 17: ...n the new socket to match those of the original socket and solder the new socket in place Reinstall the two screws to secure the new socket in its proper position Reinstall the back cover securing wit...

Page 18: ...wn relative to the negative output of the bridge rectifier which is the zero reference point These waveforms were produced using version 4 19e of the LTSpice IV circuit simulator Figure 21 Lamp Wavefo...

Page 19: ...Revision 2 Page 19 of 24 Lamp Dimmer Waveforms continued Figure 23 Lamp Waveforms at Low Intensity 20 Setting of Intensity Control Figure 24 Lamp Waveforms during Current Limiting 80 Setting of Inten...

Page 20: ...U Electronics Revision 2 Page 20 of 24 LED Bar Graph Display Waveforms Figure 25 Filtered DC Power Supply Line at Maximum Lamp Intensity 100 Setting of Intensity Control Figure 26 Bar Graph Comparator...

Page 21: ...e 21 of 24 LED Bar Graph Display Waveforms continued Figure 27 Clamped Control Signal to Comparators at Medium Lamp Intensity 50 Setting of Intensity Control Figure 28 Comparator IC1 B Inputs with 6V...

Page 22: ...lamp socket Item BW 990 Price 16 75 Philips 7388 halogen lamp Item BW ESB Price 6 51 Caig Laboratories Inc URL www caig com Telephone 858 436 8388 DeoxIT D5 Spray Contact Cleaner Item D5S 6 Price 18 9...

Page 23: ...BH2 BHS REPAIR MANUAL DIFFERS FROM THE SCHEMATIC PRESENTED HERE IN THE WIRING OF THE CONTROL VOLTAGE CLAMP SEE DETAIL 2 NOTES AC IN BROWN INTENSITY SLIDER COPYRIGHT C 2014 CARL HUNSINGER HALOGEN LAMP...

Page 24: ...IC ON PAGE 98 OF THE OLYMPUS BH2 BHS REPAIR MANUAL DIFFERS FROM THE SCHEMATIC PRESENTED HERE IN THE WIRING OF THE CONTROL VOLTAGE CLAMP SEE DETAIL 2 NOTES AC IN BROWN 1 3 10 16 HALOGEN LAMP 6V 20W G4...

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