OlympusBH‐2(BHT/BHTU)Electronics Revision2 Page9of24
CommonProblemswiththeBHT/BHTUElectronics
The electronics in the BHT/BHTU microscopes have proven to be remarkably reliable over the years, but with heavy
usage,failure s do occur.The mostlikely problems in the electronics will be bad orintermittentcontacts in the lamp
houseanderraticlampintensityduetodust,dirt,andoxidationwithinthe
intensitycontrol.
Wornoroxidizedcontactsinthesocketinthelamphousewillcausethehalogenbulbtonotilluminate,toflicker,orto
illuminate only intermittently.If a replacement lamp house is not available, the troublesome lamp socket may be
replacedwithanewone,asdescribedlater
inthisdocument.Itmayalsobepossibletoeffectatemporaryrepairby
disassemblingtheexistinglampsocketandcleaningtheoxidizedcontactswithemerypaper,butthisshouldbeviewed
asatemporaryfixonly.
Dust, dirt, and oxidation within the intensity control can cause erratic lamp intensity as
the control slider is moved
throughout its adjustment range.This can usually be corrected by spraying a short blast of volume control/contact
cleaner(afterunpluggingtheAClinecord)intotheintensitycontrolandmovingthesliderthroughoutitsfullrangeof
motionafewtimestodistributethecleaner
(seeAppendix1ofthisdocumentforasuggestedcleaner).Exercisecaution
whensprayingthe cleaner into the control so as tominimize overspray and blow‐backonto nearby components.Be
sure to allow the contact cleaner sufficient time to evaporate out of the control before re‐applying power to the
electricalbase.
ObtainingReplacementComponents
TheBHT/BHTUmicroscopesarenolongersupportedbyOlympus,andwithfewexceptions,factoryreplacementparts
arenotavailable.Someelectri calparts(orsuitablesubstitutes)areavailablefromthirdpartysources,andtheseparts
arelistedinAppendix1ofthisdocument,alongwithsourcesandpricing.
TheBHT/BHTUmicroscopeswere
verypopularintheirday,andusedstandsandtheirvariousbitsandpiecesfrequently
showupforsaleonebay.Ifnecessary,replacementelectricalcomponentscanbesalvagedfromaspareelectricalbase.
Ifexactreplacementscannotbefound,makesurethatanysubstitu tepartschosenforrepairshave
suitableelectrical
andmechanicalspecificationsandthattheyareinstalledinsuchawaythatitisnotpossiblefortheoperatortocontact
anylivevoltagepointswhileusingthemicroscope.
PowerTransformer
Thegoodnewshereisthatthepowertransformer(showninFigure7)rarelyfails.Thebadnewsisitmaybedifficultto
locateasuitablesubstituteforitifiteverdoesfail,duetotheuniqueformfactorwhichallowsittofitintothebaseof
theBHT/BHTUstand.Ifasuitablesubstitutecannotbefoundforthetransformer,this maybeagoodtimetostarton
thatLEDconversionproject,whilelookingforanotherelectricalbase.
Figure7–PowerTransformerMountedtoBHT/BHTUElectricalBase(100/115VVersion)
To Next Page
Loading...
