Backlight Board Hom Case Kho Kev Ntsuam Xyuas
Feb 23, 2023
Tam sim no, LCD TV backlight board qauv muaj ntau ntau, cov chaw tsim khoom sib txawv, ntau qhov sib txawv ntawm LCD, lub backlight board txawv, txawm tias tib lub chaw tsim khoom ntawm tib lub qauv ntawm LCD siv lub backlight board yog qee zaum txawv. Thiab lub backlight board yog qhov loj tshaj plaws ntawm LCD TV lub zog noj, tab sis kuj yog qhov loj tshaj plaws tam sim no, qhov siab tshaj plaws voltage, yog li tus nqi tsis ua hauj lwm yog siab, vim hais tias cov backlight boards tsis tshua muaj schematic daim duab, los soj ntsuam qhov tsis ua hauj lwm ntawm lub hauv paus ntsiab lus, kev daws teeb meem nyuaj heev, tab sis kuj yog qhov muag tsis pom. Cov kws ua haujlwm tau ntsib nrog lub teeb pom kev ua haujlwm tsis zoo feem ntau siv cov txheej txheem hloov lub teeb pom kev zoo los daws, tab sis qee cov qauv ntawm lub teeb pom kev zoo yog qhov nyuaj rau nrhiav, yog li peb yuav tsum nyob rau hauv qhov tseeb txij nkawm sai li sai tau los ua tus tswv txoj kev kho dua tshiab.
Lub functional muaj pes tsawg leeg ntawm lub backlight board
Backlight board Cheebtsam yog tsim los ntawm plaub qhov chaw: oscillator, lub zog amplification, high voltage tso zis, tiv thaiv kom paub. Lub luag haujlwm ntawm txhua ntu yog raws li hauv qab no.
Backlight vaj huam sib luag ua haujlwm qhia
Oscillator: tsim 60-100KHZ oscillating square wave signal.
Fais fab amplification: Amplify lub teeb liab tsim los ntawm oscillator kom txaus lub hwj chim rau lub teeb.
High voltage tso zis: Boost lub teeb liab tom qab fais fab amplification thiab hloov nws mus rau sine yoj tso zis rau lub teeb CCFL teeb.
Kev tiv thaiv kev tiv thaiv: kuaj xyuas qhov hluav taws xob tawm ntawm lub teeb pom kev zoo ntawm lub teeb pom kev zoo thiab qhov ua haujlwm tam sim no thiab kev ua haujlwm ntawm CCFL teeb, yog tias muaj qhov txawv txav, tswj lub oscillator kom nres cov zis thiab nkag mus rau hauv lub xeev tiv thaiv.
Backlight board ua hauj lwm tej yam kev mob
CPU muab cov teeb liab hloov pauv tswj teeb liab (BL-ON) thiab teeb pom kev ci ntsa iab ntawm lub teeb ci DIM rau lub teeb pom kev zoo.
Lub tshuab hluav taws xob ntawm lub teeb pom kev teeb pom kev zoo suav nrog lub hwj chim ntawm lub hwj chim amplification, qhov oscillation tswj qhov, thiab qhov kev tiv thaiv kev tiv thaiv ib feem. Rau lub hwj chim amplification, tam sim no fais fab mov ntawm lub backlight board ntawm 32-inch thiab saum toj no screen yog 24V, 6-10A, thiab lub backlight board ntawm 26-inch thiab hauv qab no screen loj feem ntau adopts 12V fais fab mov, thiab lub hwj chim mov ntawm lub oscillation tswj thiab tiv thaiv nrhiav tau ib feem yog feem ntau 5V los yog 6V, uas yog tau los ntawm 12V los yog 24V tom qab step-down thiab voltage kev cai.
Peb lub ntsiab ntawm cov chip ua haujlwm, uas yog.
1. nti fais fab mov
2. nti pib zog tus pin (siab)
3. tus pin dimming (siab)
Backlight kev ua tsis tiav
1. Backlight tsis teeb
2. Backlight flashing tiv thaiv
3. Lub teeb ci ntsa iab rau lub sijhawm tiv thaiv
Backlight board kho txoj kev
Thaum kho lub backlight board kom paub cov yam ntxwv ntawm lub backlight raj, lub teeb pom kev zoo lub hauv paus ntsiab lus thiab cov muaj pes tsawg leeg ntawm lub backlight board, ua hauj lwm hauv paus ntsiab lus. Txawm hais tias cov duab ntawm lub backlight board, cov qauv qauv muaj pes tsawg leeg sib txawv, tab sis lub hauv paus ntsiab lus tseem ceeb yog tib yam, ntev li ntev raws li lub hauv paus ntsiab lus, koj tuaj yeem txheeb xyuas qhov txhaum, qhov teeb meem ntawm backlight board yog tsis tshua muaj 3-4 hom, lub backlight. board lub high-voltage tso zis thiab lub hwj chim amplifier Circuit Court txoj cai yog yooj yim, ntau tshaj li kev siv tag nrho-bridge / ib nrab-bridge tsav, feem ntau yog siv MOS hlab los yog fais fab modules.
Backlight pawg thawj coj saib xyuas ua ntej kom ntseeg tau tias lub hwj chim muab ib feem ntawm kev ua haujlwm ib txwm muaj. Ntawd yog, cov khoom siv hluav taws xob standby 3.3V lossis 5V, 12V, 24V, PFC Circuit Court ua haujlwm zoo, ua ntej lub teeb rov qab tuaj yeem hloov kho.
Kev tshuaj xyuas tuaj yeem raug tshem tawm ntawm lub rooj tsavxwm fais fab mus rau lub rooj tsavxwm tseem ceeb ntawm txoj kab, qhov standby voltage 5V feem nrog STB (standby tswj) BRI (dimming) thiab BL-ON (backlight tswj) 3 ko taw txuas ua ke, lub teeb pom kev zoo yuav tsum muaj peev xwm ua kom pom kev, cov kauj ruam no tuaj yeem txiav txim siab seb qhov teeb meem ntawm lub rooj tsav xwm tseem ceeb lossis cov teeb meem ntawm lub hwj chim mov.
Yog hais tias lub backlight raj tsis teeb tag nrho, nws txhais tau hais tias tsis muaj mem tes teeb liab ntxiv rau lub backlight inverter. Peb tuaj yeem hloov kho lub teeb ci rov qab thaum lub teeb pom kev zoo tuaj yeem pom raws li kab cheb Circuit Court kom kho dua.
Backlight tswj nti muaj tus yam ntxwv, nyob rau hauv lub nti tsuas yog lub hwj chim ntawm 2 vib nas this tsis muaj kev tiv thaiv los ntawm kev tawm tswv yim pins tswj, yog ib tug mem tes tso zis, tom qab pib tau txais nws ib txwm tawm tswv yim teeb liab los ntawm lub nrhiav kom tau pins ua ntej nkag mus rau hauv ib txwm ua hauj lwm lub xeev. Yog tias tsis muaj cov teeb liab tawm tswv yim lossis cov teeb meem tawm tswv yim txawv txav tom qab pib, lub nti yuav nkag mus rau hauv lub xeev kev tiv thaiv thiab tsis txhob tso tawm cov teeb liab excitation. Peb tsuas yog siv qhov tshwj xeeb no txhawm rau kuaj pom tus mem tes tso zis tus pin ntawm lub backlight tswj IC thaum lub hwj chim qhib, saib seb nws puas muaj qhov hluav taws xob tso tawm thaum lub hwj chim qhib, koj tuaj yeem siv oscilloscope los ntsuas lub teeb liab waveform ntawm cov zis. tus pin, koj tuaj yeem siv cov ntaub ntawv multimeter AC voltage los ntsuas seb puas muaj cov khoom siv mem tes.
Peb txiav txim siab qhov txhaum raws li tus nqi voltage ntawm no yog nyob rau hauv lub backlight tswj nti raws li lub hauv paus ntawm lub Circuit Court, los yog nyob rau hauv lub back-end circuit. (Nws yuav tsum tau muab sau tseg tias lub nti tiv thaiv tom qab xav tau lub hwj chim tawm thiab ces pib tom qab li 2 vib nas this ntawm cov zis) Yog hais tias muaj ib tug teeb liab tso zis, koj muaj peev xwm txiav txim qhov txhaum nyob rau hauv lub rear tsav ib feem. Txwv tsis pub, qhov txhaum nyob rau hauv lub backlight nti tswj ib feem. Peb tuaj yeem ntsuas seb puas muaj AC excitation teeb liab tso tawm ntawm qhov tso tawm ntawm nws qhov backstage excitation transformer (vim tias qhov kev khiav hauj lwm zaus ntawm lub backlight Circuit Court yog li 56KHZ tshaj qhov zaus teb ntawm peb cov multimeter zoo tib yam, yog li tsis muaj qhov tseeb voltage tus nqi, cov digital. 'meter' feem ntau yog ~ 30 volts los yog li ntawd, lub tshuab ntsuas hauv ~ 10 volts los yog li ntawd. )
Daim ntawv Excitation tsis zoo ib yam, tab sis nws txoj kev saib xyuas yog tib yam li hauv qab no yog nws ob peb daim duab txiav txiav.
Thaum cov zis pulse ntawm nws excitation transformer yog ib txwm, peb yuav txuas ntxiv ntsuas cov kauj ruam mus rau theem tom ntej kom txog rau thaum peb pom qhov luv luv Circuit Court point ntawm mem tes.
Cov txheej txheem overhaul saum toj no yog txhawm rau txhim kho lub backlight Circuit Court tsis teeb txhua lub sijhawm tom qab lub hwj chim ntawm txoj kev hloov kho sai thiab zoo.
Ceev faj.
Thaum ntsuas lub teeb liab mem tes, thov ua ntej muab lub ntsuas ntsuas ntsuas ntsuas ntsuas qhov ntsuas qhov chaw thiab tom qab ntawd qhib lub hwj chim, txhawm rau tiv thaiv kev tiv thaiv sab hauv ntawm multimeter kom cuam tshuam rau lub xeev ua haujlwm ntawm lub sijhawm tom qab ua rau tsis tsim nyog, lossis ncaj qha disconnect. lub hwj huam mov ntawm theem kawg los thawb lub raj ua ntej.
Backlight board kho rooj plaub
Fault one: lub teeb rov qab puas lawm (los yog tawg)
Qhov tshwm sim tsis ua haujlwm: lub sijhawm ntawm lub zog ntawm lub vijtsam tuaj yeem pom los pib lub teeb-emitting, qee zaum koj tuaj yeem pom ib qho tsaus nti, tab sis tom qab ntawd tua, tom qab tua, lub LCD npo rau lub teeb pom kev tsaus ntuj, lub suab. yog li qub.
Kev tsom xam tsis ua haujlwm: Thaum lub teeb lub teeb rov qab tawg, nws cov teeb pom kev sib raug zoo yuav ua piv txwv lub teeb liab mus rau lub teeb pom kev ntawm lub teeb pom kev tawm tswv yim ntawm oscillation tswj IC, kev tiv thaiv kev tiv thaiv hauv Circuit Court tom qab kev tiv thaiv qeeb los txiav tawm cov teeb liab tawm. Qhov no yog vim li cas vim li cas lub vijtsam tuaj yeem pom kom muaj lub teeb-emitting ua haujlwm ntawm lub sijhawm ntawm lub zog, tab sis tom qab ntawd tua. Pib lub teeb vim tias lwm lub teeb pom kev zoo ib txwm teeb; ces extinguished yog vim muaj kev tiv thaiv Circuit Court ntawm lub tawg backlight tube kev tiv thaiv, lub backlight board raug kaw tso zis tshwm sim.
Kev kho mob: Rau qhov tshwm sim ntawm lub hwj chim ntawm flashing ib zaug thiab tawm, kom thaum kawg paub meej qhov txhaum, lub oscillation tswj IC backlight tube tawg nrhiav kom tau cov tswv yim (feem ntau OLP) voltage rau 2V los yog ntau tshaj, lub hom phiaj yog nqa lub backlight raj tawg tiv thaiv kev tswj. , kuj tseem muaj IC los txo qhov hluav taws xob ntawm ko taw no kom tshem tawm qhov kev tiv thaiv, lwm lub teeb ci tag nrho, ob qho tib si ntawm lub teeb pom kev puas ntsoog hauv cheeb tsam yog tsaus me ntsis.
Qhov no yog txoj kev kho thaum muaj xwm txheej ceev, vim tias qhov xwm txheej no yuav tsum tau hloov lub vijtsam LCD los daws, yog tias tsis hloov lub vijtsam LCD yuav tau hloov lub teeb rov qab, thiab hloov lub teeb txij nkawm yog qhov nyuaj thiab pheej hmoo. Lub sijhawm no, nws tau pom zoo tias qhov ci ntsa iab ntawm tag nrho LCD npo kom hloov mus rau qhov loj dua, vim lub LCD npo sab hauv lub teeb qhia, kev puas tsuaj rau lub teeb tsis yog qhov zoo rau kev siv cov nyhuv. Kev muaj peev xwm ntawm tes, yog tias qhov chaw ntawm lub teeb tawg nyob hauv nruab nrab ntawm lub vijtsam, thov hloov lub teeb no mus rau sab saum toj ntawm lub vijtsam, kom qhov kev pom ib txwm pom tsis pom. Ua li no yuav tsis cuam tshuam rau kev nyab xeeb ntawm Circuit Court thiab tuaj yeem siv nrog kev ntseeg siab.
Thaum lub teeb puas lawm, vim tias lub teeb tsis ua haujlwm, tsis muaj qhov hluav taws xob poob thoob plaws nws cov terminals, sib xws rau cov khoom siv hluav taws xob ntau ntawm cov hluav taws xob tiv thaiv overvoltage rov qab los ua haujlwm, tom qab ntawd cov kauj ruam-up transformer input Circuit Court yuav tsum raug txiav. los tiv thaiv overvoltage tiv thaiv kev ua.
Qee lub sij hawm lub teeb kev laus, nws qhov kev pib ua haujlwm tsis zoo, raws li qhia los ntawm: pib qeeb, pib lub sijhawm ntau dua 2S, lossis ntev dua, ntau dua li kev tswj hwm lub teeb rov qab IC teem sijhawm tiv thaiv ncua sijhawm, tseem tsis tuaj yeem pib ib txwm, kev tiv thaiv kev tiv thaiv Circuit Court. los txiav txim lub backlight raj disconnection txhaum, kuj kaw lub excitation teeb liab tso zis. Qhov xwm txheej no yog ua tib yam li saum toj no.
Qhov teeb meem thib ob: lub teeb rov qab tsis flash, lub fuse ntawm lub teeb ci ntsa iab
Kev soj ntsuam tsis ua haujlwm: fuse tshuab txhais tau hais tias lub teeb pom kev rov qab muaj qhov cuam tshuam loj heev, luv luv Circuit Court (mos overcurrent feem ntau yuav tsis tshuab lub fuse) tau ua rau lub voj voog luv luv rau cov khoom, lub sijhawm no tsis txhob maj hloov lub fuse fais fab, txwv tsis pub qhov txhaum yuav nthuav dav ntxiv, thiab tseem cuam tshuam rau kev nyab xeeb ntawm lwm cov circuits ntawm lub tshuab.
Qhov tsis ua hauj lwm no yog lub hwj chim amplifier Circuit Court Cheebtsam, MOS raj los yog complementary MOS module tawg, luv luv Circuit Court, uas yog ib qho tseem ceeb tshaj plaws ua rau qhov tsis ua hauj lwm no.
Kev tshuaj xyuas thiab kho cov kev ua tsis tiav, koj yuav tsum ua tib zoo saib xyuas lub rooj tsav xwm hauv Circuit Court, tshwj xeeb tshaj yog MOS raj, MOS raj tsav module tsis muaj xim daj, tawg txawv txav, lub teeb pom kev zoo dav dav muaj ntau pawg ntawm tib lub voj voog tsav, koj tuaj yeem sib piv cov zoo li qhov txhaum uas pom nyob rau hauv cheeb tsam dav dav. Qhov xwm txheej no tuaj yeem hloov tau nrog tib hom tsav MOS raj lossis tsav MOS module, yog tias tsis yog tib tus qauv, koj tuaj yeem xaiv qhov tsis sib xws, tshwj xeeb tshaj yog nyob rau hauv-kuj kuj zoo ib yam li kev hloov, txhawm rau tswj cov kev sib tw. sib npaug ntawm tus choj rov qab caj npab.
Qee lub sij hawm, lub backlight board fuse tshuab, lub hwj chim module tawg luv luv Circuit Court, tab sis cov tsos ntawm lub hwj chim module xim tsis muaj kev hloov, uas yog siv cov multimeter kuj cov ntaub ntawv rau kev tshawb nrhiav, nyob rau hauv cov ntaub ntawv ntawm lub backlight board tsis energized. , feem, piv nrog rau kev tshawb pom ntawm txhua lub zog module taw mus rau hauv av kuj tus nqi, yog tias muaj qhov tsis zoo ntawm cov module, tuaj yeem pom tias muaj qhov txhaum.
Lwm yam khoom puas tsuaj, feem ntau yuav tsis ua rau lub fuse tshuab.
Kev kho mob: Rau lub teeb ci ntsa iab tsis ci, fuse lub teeb ci ntsa iab, kos rau lub hwj chim module puas thiab hloov, koj tuaj yeem siv lub zog ntawm lub vijtsam LCD saib qhov ci, thiab ua tib zoo saib xyuas seb lub backlight board muaj overheating, pa taws tshwm sim; txwv tsis pub, kuj yuav tsum xyuas seb lub kauj ruam-up transformer nws tus kheej luv luv-circuit, vim hais tias cov kauj ruam-up transformer luv luv-circuit los yog hauv zos luv-circuit nws thiaj li yuav ua rau lub hwj chim module tawg, luv-circuit.
Yog hais tias lub kauj ruam-up transformer puas lawm, vim hais tias muaj ob hom backlight boards, ib tug siv ib tug step-up transformer backlight board, siv EEFL teeb; los yog siv txoj kev sib npaug inductance los xyuas kom meej tias CCFL teeb tau tsav nyob rau hauv tib lub sijhawm. Qhov no transformer vim qhov loj ntawm cov txheej txheem ntau lawm, rwb thaiv tsev kev ua tau zoo tuaj yeem lav, feem ntau tsis yooj yim rau kev puas tsuaj.
Lwm qhov yog siv ntau lub kauj ruam-up transformers los txhawb ntau lub CCFL teeb backlight board, transformer yog lub luag hauj lwm rau lub teeb, 16 teeb yuav xav tau 16 transformers, tam sim no pom tias qhov transformer no puas feem pua. Yog tias muaj kev puas tsuaj, yuav tsum tau hloov nrog tib hom kev hloov pauv hloov pauv, yog tias tsis yog, txoj kev kho mob xwm txheej ceev mus rau qhov tsis ua haujlwm ntawm cov kauj ruam-up transformer, thawj disconnect, nws coj backlight raj tsis ua hauj lwm, tab sis kuj nqa lub backlight board backlight tube disconnect kev tiv thaiv, kom ntseeg tau tias kev ua haujlwm ntawm lwm lub teeb tsis tau txais kev cuam tshuam. Txhawm rau kom muaj daim tom qab yog, thiab tom qab ntawd rov qab kho qhov qub qub.
Fault peb: lub backlight tsis teeb, lub fuse tsis zoo
Kev tsom xam tsis ua haujlwm: hom kev ua tsis tiav no suav nrog ntau yam loj, yuav tsum xub xyuas lub teeb pom kev zoo ntawm lub teeb pom kev, tswj kev sib txuas DC fais fab mov, teeb liab rov qab hloov, thiab tswj qhov ci ci yog qhov qub, kom paub meej tias tsis muaj teeb meem ua ntej txiav txim siab lub teeb pom kev zoo. board overhaul, lub dav backlight board nws lub hwj chim mov, tswj interface thiab lwm yam sockets yog kom meej meej cim nyob rau hauv lub luag hauj lwm ntawm tus pins, ko taw los ntawm ko taw nrhiav kom tau qhov chaw txhaum.
Qhov thib ob, kom paub meej tias lub oscillation tswj IC VCC fais fab mov thiab ua kom lub davhlau ya nyob twg (ENA) pib voltage, lub hwj chim amplifier Circuit Court fais fab mov (12V lossis 24V) yog qhov qub, yog tias ib txwm xav txog seb lub xeev tam sim no ntawm kev tiv thaiv, kev saib xyuas tiag tiag, pom tias backlight tswj IC kev puas tsuaj yog tsis tshua muaj heev, feem ntau yog rau kev tiv thaiv ntawm cov teeb meem ntawm Circuit Court.
Kev kho mob: hauv kev saib xyuas lub teeb pom kev tsis pom kev, lub fuse yog qhov tsis raug, txoj hauv kev zoo tshaj plaws los txiav txim siab yog nqa cov kev tiv thaiv kev ua haujlwm, qhov no yog vim tias qhov tsis ua haujlwm feem ntau yog ib feem ntawm lub backlight board muaj qhov txhaum, uas. pib qhov kev tiv thaiv kev tiv thaiv Circuit Court, thiab tom qab ntawd txiav tawm qhov tso tawm ntawm lub teeb liab excitation, uas ua rau qhov tshwm sim tsis muaj teeb pom kev zoo.
Cov qauv sib txawv ntawm oscillation tswj IC, nws qhov kev tiv thaiv dhau-voltage (OVP \ CLAMP) theem pib kuj txawv me ntsis, feem ntau 2-3V, feem ntau, qhov hluav taws xob tiv thaiv hluav taws xob tshaj tawm rau qib qis ntawm kev ua haujlwm ib txwm muaj, ntau dua tshaj li theem pib mus rau hauv lub xeev tiv thaiv dhau-voltage, yog tias koj xav nqa cov kev tiv thaiv tshaj-voltage, ncaj qha mus rau over-voltage tiv thaiv chaw nres nkoj hauv av tuaj yeem ua tau.
Backlight tube tawg tiv thaiv chaw nres nkoj OLP, feem ntau tsis tshua muaj kev tiv thaiv, qib siab 1.5V thaum ua haujlwm ib txwm muaj, yog tias koj xav nqa lub teeb rov qab lub raj tawg tiv thaiv, tsuas yog ntxiv qib siab dua rau tus pin no tshaj li qhov pib tswj tau.
Nyob rau hauv lifting lub backlight tube tawg tiv thaiv tib lub sij hawm, kuj yuav tsum tau over-voltage tiv thaiv Circuit Court, tso zis tam sim no nrhiav tau tawm tswv yim Circuit Court yog lifted tib lub sij hawm, tag nrho cov kev tiv thaiv yog lifted, lub hwj chim rau saib lub backlight board tsis muaj pa luam yeeb. , hluav taws kub tshwm sim, thiab npaj kaw lub hwj huam mov, kaw lub hwj huam mov, kov lub backlight board tsav cov khoom tso tawm los ntawm tes, tsis muaj qhov pom tseeb qhov kub thiab txias, qhov teeb meem kub, yog tias qhov kub siab dhau, qhov txhaum yog nyob rau hauv cov ceg no. , qhov kev kho txhaum cai, overvoltage, overcurrent nrhiav pom kev tawm tswv yim Circuit Court yuav tsum tau rov qab los rau hauv lub xeev qub, lub teeb tawg tiv thaiv tsis tas yuav rov qab los, tsis muaj kev cuam tshuam rau hauv Circuit Court.
Nyob rau hauv kev saib xyuas ntawm lub backlight board, ntau qhov chaw ntawm qhov txhaum yog lub hwj chim amplifier module (MOS tube) thiab high-voltage transformer, ob qhov no kuj yog cov feem ntau rov qab Circuit Court ntawm lub backlight board.
Lus Cim: Tom qab lub teeb ci ntsa iab tau ua kom muaj zog ua haujlwm, tsis txhob siv lub tshuab multimeter lossis oscilloscope los ntsuas nws cov zis hluav taws xob siab, uas yuav ua rau "rub arc"
Thaum ntsuas nrog oscilloscope, nyob rau hauv cov ntaub ntawv uas lub high-voltage tso zis tsis txuas nrog lub backlight raj, series resonant tso zis Circuit Court nyob rau hauv ib tug qhib lub xeev, thiab lub ntsuas waveform yuav tsum tsis txhob sine yoj.
Cov saum toj no piav qhia txog ib feem ntawm kev saib xyuas lub teeb pom kev zoo rau kev siv.
