Huntron_HTR-1005B1S-Maintenance 电路图.pdf

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1、OAt DcQdJNLr(Q)N Lr22ccgD MAINTENANCEMANUAL FOR MODELS HTR 1005815 HTR 100581E5 HTR 100581J5 HUNTRON INSTRUMENTS, INC.15123 Hwy.99North.Lynnwood, WA98037.(800)426-9265 (206)743-3171 Telex152951 RadioFans.CN 收音机爱 好者资料库 TABLE OF CONTENTS SPECIFICATIONS. 2 GENERAL DESCRIPTION.3 THEORY OFOPERATION.5 The

2、 Test Signal. 5 Testing Reactive Components. 8 CIRCUIT DESCRIPTION Signal Section. 10 Oscillator. 12 PowerSupply. 12 Cathode Ray Tube Circuit. 12 INTERNAL SETUP AND ADJUSTMENTS .17 TROUBLE SHOOTING General Information. 19 Power Supply . 19 Signal Section. 22 CRT Section. 24 OscillatorSection.24 LIST

3、 OFREPLACEMENT PARTS. 25 SETUP, ADJUSTMENT bipolarand MOSintegratedcircuits,including bothanaloganddigital;certaintypesofcapacitorsandinductors. Includedasstandardequipmentwitheach TRACKERis asetofHUNTRONMICRO PROBES.The MICROPROBEleadsplugintothefrontpaneltestjacks.MICROPROBES have specialtipssotha

4、ttheycan be usedtocontactverysmallcomponentterminalsandsmall PCBetchingswithoutthedangerofshortingadjacentterminalsand leads.Alsoincludedas standardequipmentis acommontestleadwhichis usedwiththe TRACKERin theCompar- a-trace mode (see Figure2). FRONT PANEL CONTROLSANDINDICATORS (RefertoFigure1) DISPL

5、AY CONTROLS: BRIGHTControlstheintensityofCRTdisplay VERTControlstheverticalpositionofCRTdisplay HORIZControlsthehorizontalpositionofCRTdisplay RANGE SELECTOR SWITCH: Threeinterlockingpushbuttonswitchesselectoneofthree ranges characterized below. HIGHSelects120 VP-Psinewavetestsignal MEDSelects40VP-P

6、sinewavetestsignal LOWSelects20 VP-Psine wavetestsignal CHANNELSELECT SWITCH: Threepositionswitchthatselectsthechanneldisplayed. ToppositionselectsCHANNELA. CenterpositionselectsALTERNATE MODE. BottompositionselectsCHANNELB. (ALTERNATE MODEalternatesdisplaybetweentwoinputsat 0.8 HzforGood/Bad compar

7、ison.) ON/OFF SWITCH2-positionpushbottonthatturnstheTRACKERONor OFF CHANNELA LEDIndicatesCHANNELAinputis beingdisplayed CHANNELBLEDIndicatesCHANNELBinputis beingdisplayed ON/OFF INDICATOR LEDIndicatesPOWER is ONorOFF RED TERMINALCHANNELA INPUT YELLOWTERMINALCHANNELB INPUT BLACKTERMINALINSTRUMENTCOMM

8、ON 3 CO.ON -:i=!;:=;!l.r.Ju.-tF-TT11LCHANNElBlED CHANNEL BINPUT+ CRTINTENSITYVERTICALPOSITION CRTDISPLAYHORIZONTALPOSITION rrnr;IFiHANNELSELECTSWITCH lOWRANGESELECT MEDIUM RANGE SELECT HIGH RANGESELECT POWERON/OFFSWITCH LOCATIONS OF FRONT PANEL CONTROLS FIG.I The HUNTRON TRACKERcanalternateautomatic

9、allybetween thedisplaysofCHANNELA and CHANNEL B inputs. This allows the usertodirectly compare the displayofthe suspectcircuit tothatofa known goodcircuitfor QA ortroubleshooting.Figure 2showshow a TRACKER can be usedtocompare a known good boardwitha board under test. EBIIIIOiiiiif-/= DO IJDH aD CHA

10、NNEL SELECTION SWITCH CHANNEL A LE.D. RED TEST TERMINAL BLACK TEST TERMINAL YELLOW TEST TERMINAL CHANNEL B L.E.D. COMPARING A KNOWNGOODBOARDWITH ABOARDUNDERTEST FIG.2 4 THEORYOFOPERATION TheHUNTRONTRACKERapplies a test signal acrosstwoterminalsofthe device being tested. This test signal causes a cur

11、rent to flow through the device and a voltage drop across its terminals. Thecurrentflowis processed insucha way astocause a verticaldeflectionofthescopetrace, whilethevoltageacrossthetestcomponentcausesahorizontaldeflectionofthescopetrace. THETESTSIGNAL Thissignal is an80Hz sine wavethatalternatelya

12、ppliespositiveand negativevoltagesacross thecomponentbeing tested. In an opencircuitconditionthepositivehalfcyclegenerates theleftsidetrace on the CRT, and therightside tracecomesfrom negativehalfcycle. The 80 Hztestsignalis generated on the OscillatorBoard and presented at thefrontpaneltestterminal

13、sthroughasignaltransformer. Thetransformerhas the dual purposeofadjustingthetestvoltagelevelforthevariousranges andselectingtheimpedancelevelofthevariousranges. The test signal, as presented at the front panel, electrically appears as though it is being originated by avoltagegeneratorwitha seriesout

14、putimpedance. The opencircuitvoltageandgenerator impedancearebothdifferentforall three ranges. Figure 3showstheelectricalequivalentofthegeneratorsectionandhowthevoltageacross the terminalsaffectsthe horizontal and vertical deflection platesoftheCRT.Shown is the symbolic representationofa voltage gen

15、erator (GEN)witha series internal impedance(Zgen)and a current sensingpoint(I).AcrossthesenetworkelementsaretwotestpointsA and COM. ZGEN GEN +20 tV+- SIGNAL-20V SOURCE A COM RANGE=MEDIUM TEST= OPEN CIRCUIT flG3 An opencircuit(such asthatshowninFigure3)has zerocurrentflowingthroughthetestleads and ha

16、smaximumvoltageacrossthetestleads. In the HIGH and MEDIUM rangesthisis represented by astraighthorizontaltracefrom themaximumlefttothemaximumrightofthe CRT. In the LOW range, an opencircuitconditionisshownas adiagonaltracefromtheupper righttothelowerleftcornerofthe CRT.Figure4ashowsscopetracesin HIG

17、H, MEDIUM and LOW ranges. When thetestleads are shorted,maximumcurrentflowsin the leads and there is zerovoltage acrossthe lead. This isindicatedby a verticaltracefrom thetopto thebottomofthe CRT on all ranges (seeFigure4b). 5 + HIGH + MED TEST:OPENCIRCUIT FIG.4. LOW + HIGHMEDLOW TEST:SHORT CIRCUIT

18、FIG.4b A pure resistance across the test leads would create both currentflowin and voltage drop across theresistancewhichwouldappear on the CRT as adeflectedstraighttrace. The HIGH and MEDIUM rangeswouldhave the tracedeflectedclockwisearound thecenterofthe CRT from the horizontalposition(open circui

19、t),whiletheLOW rangewouldhave thetracedeflectedclock- wisefrom the opencircuitdiagonalposition.Onall ranges the lengthofthetrace is reduced becauseoftheinternal voltagedropacross Zgencaused by theresistorload and the trace is rotatedtowarda more verticalpositionbecauseofthe increased currentthrought

20、heload. The amountoftracereductionandrotationdepends upon thetestresistance value and the range chosenforthetest. Since a pure resistance is a linear electrical element, the resulting trace will alwaysbeastraight line. Non-linearelectricalelementsthatare not reactivedonot give astraightline over the

21、 entire trace length.Figure 5shows the trace with a33kohm resistor across the test leads in the MEDIUM range. The resistor causes the horizontaldeflectionvoltagetobereduced becauseofthe current flowthroughthe resistor. The verticaldeflectionvoltage isproportionaltothecurrentflowand theresultingpatte

22、rn is aclockwiserotated tracethatisshorterthan the opencircuittrace. The peakcurrentthroughtheresistoris 320microamps.The actualshortcircuitpeakcurrentis 730 microamps.Thegeneratorimpedance intheHIGH range is75kohms, in the MEDIUM range is 27 kohms, and in the LOW range is56ohms. 32010 PEAKV ZClEN G

23、EN .2 rv_ SIGN20- SOlRCE RANGE:MEDIUM TEST33KRESISTOR A 33K COM FIG.5 6 + c:r CLOCKWiSEROTATION A non-linearcomponentsuchas asilicondiodewouldallowa largecurrenttoflowduringthe halfcyclewhenitis forward biased and verylittlecurrenttoflowduringthe reverse biasedhalf cycle. Thevoltagedropacrossthe for

24、ward biasedjunctionwouldbe small (i.e. 0.7V.),andthis wouldappear as a nearshortcausinga verticaltracetoappearduringthatportionofthe cycle. The reverse biasedconditionwouldcause verylittlecurrenttoflowandwouldlooklike an open circuittraceon the CRT. Figure6ashowsasilicondiodejunctionbeing observedwi

25、ththe TRACKERin the LOW range, whileFigure 6bshowstracesin HIGH and MEDIUM ranges. 170Qf PEA ZGEN tIOV( -0V A IN914 IOY( PEA -.7V COM RANGE;LOW TEST;DIODE + RANGE;HIGH TEST;DIODE FIG.60 FIG6b RANGE-MED TEST;DIODE Figure7showsa33kohmresistorbeingshuntedby asilicondiode. During thefirstha.lfofthe test

26、signalthejunctionisforwardbiased and appears as a nearshortcircuitto thetestsignal resultingin theverticaltraceshowninthesecondquadrantofFigure7.Then thetestsignal reversespolarityduring the secondhalfcycleand thediodebecomes reverse biased. The reverse biasedresistanceofthediodeismuchgreaterthan th

27、e33kohm resistance, soessentiallyall ofthecurrentflowsthroughthe33 kohmresistorcreatingthe CRTpatternshownin thefourth quadrantofFigure7. 70010( 20ro. ZGENA 33K COM IN914 .7V=t/ V-20V -=:+-+-t-III cr RANGE-MEDIUM TEST-33KRESISTOR ANDDIODEINPARALLEL FIG.7 7 Figure 8shows a silicon diode shunted by a1

28、0ohm resistor with the LOW range selected. During thefirsthalfofthe cycle thejunctionis forward biased and in parallelwiththe10ohm resistor. The combined currentsofthetwodevices in parallel is very high and causes a near vertical trace on the CRT. A vertical line represents a shortcircuit(zero volta

29、ge drop)condition,and, since thejunction does not have appreciableconductionuntila forward voltageofapproximately0.7Voltsis generated, the vertical trace is displacedtotheleftbythisamount. This is shown as thestraight vertical portionofthe trace in the second quadrantofFigure8. In the reversedirecti

30、onthediodeisessentiallyoutofthecircuitand allofthe currentflows through the resistor. This causes the trace in the fourth quadrant and partofthe second quadrant ofFigure8. 170mQ PEAl V +6V 04-07 :N-400 39 8, -1350V iEST POINT 1-+-.-_-6liREG +tBOv CI3 C 14 CI.CI6 08-011et7Cl8 1-4001 JACI +I2VrJI +- R

31、40C 3 4.7MEGluf 4OIl =7 L R6 -5 MEGHIGHVOLTAGEREStSTOR,I/2W -= R7 IMEGFOCus , 4-:lI R38 500K NTENSITY 12 7R3S -t-4-.-i_t-3K 1,6K$Dr 1IN914 1-6V MAST. HORIZ GAIN MODEL TRANSfORMERIDENTIF,CATION CHART FIG14 R25 1,6K f-I-:.!_,0c:.f_6_OH_Z_+-O-6-60-_i _Ov,50/60HZ06-6032 IOCv,SO/60HZ C4,e5f2 IfvAMPsw4 rr

32、a T-.E_R_S_W_T_C.H LINE.02vl1000 V: GNOi21 NEUTUR41-=-: Tillo-_O-.SW5 f3.!-4AMP sw, HI sw2 WO RANGESWITCHES swI LO R1068!k/% RI1l,96MEG1% t:l I- I R12 VERTICAL I 5K . T *CI OOluf IOOV J MAST.R23 RI3 R14 VERT 180K 6,22 Kh,Rp0 -c:J-;u, 1115 P rB:EJQ l.w,;8Br.- -=.Ii:)0J 0-c:J-Ri3WRIBI6 .,(-,1Q(01- R3R

33、4 I_ I FIG.15 Parts Location TOPVIEW WrJW BCEBCE CONNECTOR 11121314111PLI I , II +6V R6 2.2K R7 R5D3D4 680 120 R8 120 OUTPUT COfrlTIlIOlCClNTItOf.,-;r:-rCt(b) FIG.21 18 TESTTERMINALS.WITH DIODE RANGE. LOW (e) TROUBLESHOOTING GENERAL INFORMATION AdefectiveTRACKERshouldalwaysreceive a verycarefulvisua

34、linspectionpriorto any expensivesymptomatictroubleshooting. Burned components, fusesordarkened areas on the printedcircuitboards indicate that excessive heat has been generated, andthisisusuallyaprettygoodcluethatacomponentintheaffected area is defective. If a visual inspection on both sides of the

35、printedcircuitboard fails to indicateanobvious problem, then proceed bypowerontestingforthefollowingvoltages. RefertoFigure 14forthemain TRACKERschematic. (A)CheckpowertransformersecondarywindingAC Voltages. WINDINGN3VOLTAGES(Vrms)6.1 N411.1 N511.1 N6138 N7570 The abovereadingscorrespondtonominalAC

36、Input. (B)CheckDCVoltages (1)-1350 VAccelerationVoltage (2)6VSignalVoltage (3)+180 VDeflectionVoltage Anyoneofthe abovevoltageslistedin(A)and (B)shouldbewithin5%tolerance. Thesource ofadefectivevoltageshouldbelocatedand corrected. Ifthevoltagesasoutlinedabove are allcorrect,then proceedwithacomplete

37、checkofthe remainingvoltagesasshownon themainschematicandoscillatorschematic. A final check canbemade withanoscilloscopeto check the waveforms as shown by the triangular numberson the mainschematic.Figure 22 andFigure23listvariouswaveformsappearing on themainPCB. Afteracircuitcorrection has been mad

38、e, refertothesectionon INTERNAL SET-UP AND ADJUST- MENTSforproper CRTtracepresentation. Thefollowingsymptomaticanalysiswillhelpisolatedefectivecircuitryandlocatespecific defectivecomponents. POWER SUPPLY SYMPTOM:DEAD UNIT:Frontpanelpowerindicatorlightnoton whenfrontpanel powerswitchpushed in andpowe

39、rapplied. No CRT trace. CONDITIONS:Testterminalsopenorshorted.Allranges. PROBABLE CAUSES:(a)FusesF1andF2open. (b)PowertransformerTR2 defective. (c)PowerswitchSW4 defective. (d)RectifiersD9,D10,D11orD12 defective. (e)CapacitorsC15, C16, C17, C18, C19orC20 shorted. (f)Regulators IC3, IC4 defective. 19

40、 TEST POINTS FIG22 LOW WAVEFORMATVARIOUSTESTPOINTSONMAIPCSOARD TIME BASE:5MS/DIV RANGES MEDIUMHIGH IV/DIV 5V1DIV 5V/DIV IV/DIV 5V/DIV 2VIV IOV/DIV 5V/DIV 5V/DIV lOVIDIV 20 2V/DIV 20V/DIV 20V/DIV 20V/DIV IOV/DIV FIG.23 WA.VEFORMA.TVARIOUSTESTPOINTSONMAINPC80RD TIME BASE:5S/OIV TEST POINTS LOW 20V/DIV

41、 .IV/DIV .2V/DIV 20VlDIV 50V/DIV RANGES MEDIUM 20V/DIV .IV/DIV .2V/DIV 20V/DIV 50V/DIV 21 HIGH 20V/DIV .IV/DIV .2V/DIV 20V/OIVf 50V/DIV SYMPTOM:DEAD UNIT: Front panelpowerindicatorlighton. No trace. CONDITIONS:Testterminalsopenorshorted. All ranges. PROBABLE CAUSES:(a)No highvoltage-1350 volt. (b)Di

42、ode03,04,C9,C10, C11, C12 defective. (c)TransformersecondarywindingN7 open. SYMPTOM:Powerindicatorlighton.Onlyadotappears on CRT. CONDITIONS:Testterminalsopenorshorted. All ranges. PROBABLE CAUSES:(a)Noplatedeflectionvoltage. (b)05, 06, 07,08defective. (c)C14 shorted. (d)TransformersecondarywindingN

43、6 open. SYMPTOM:Accelerationvoltage reads -1650 Volt, andadjustingtrimpotR51does notchangevoltage. CONDITIONS:Testterminalsopenorshorted. All ranges. PROBABLE CAUSES:(a)BadtrimpotR51. (b)Defective IC2. (c)DefectivetransistorQ7. SIGNAL SECTION SYMPTOM:Dot incenterofscreen. No horizontal and vertical

44、sweep. CONDITIONS:Testterminalsopenorshorted.Allranges. PROBABLE CAUSES:(a)Nooscillatoroutput(Seeoscillatorsection). (b)SignaltransformerTR1defective. (c)6VoltatOscillatorModulemissing. (d)6Voltplatedeflectionvoltagemissing. SYMPTOM:Dot incenterofscreen. No horizontal sweep. CONDITIONS:Testterminalopen. HIGH and MED ranges. PROBABLE CAUSES:(a)IC1