Cơ bản về Monitor

8/8/2019 C bn v Monitor

1/96

Chng I - S tng qut

1. S kh tng qut ca Monitor

Bn a tr chut vo s xem ch thch

S khi ca Monitor

n hnh mu :n hnh mu l linh kin nhn tn hiu Video v tng hpthnh hnh nh theo nguyn l qut , c 3 bc nh n sc ctao ra trn n hnh mu nhnguyn l trn mu m hnh nhmu tng hp c hin th c y mu sc .

Khi ngun nui :Khi ngun nui ca Monitor hot ng theo nguyn l ngunxung hay ngun Switching, in p u vo l p c th bini kh rng t 150V AC n 250V AC, in p u ra thngcung cp 5 loi in p DC cnh cung cp cho cc khikhc trong my.

Khi qut dong :L khi c nhim v to ra cc mc in p cao cung cp chon hnh hot ng ng thi n cung cp xung dng iukhin cun li ngang li tia in t qut theo chiu ngangmn hnh .+ Tn s qut dng ca Monitor khng cnh m n phthuc vo phn gii do phn mm quyt nh .

Khi qut mnh :Nhim v ca khi qut mnh l cung cp xung mnh cho cun

li dc dn mn hnh theo chiu dc .

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2/96

Card Video :Card Video thuc phn Case c nhim v chuyn i tn hiuDigital ca my tnh thnh tn hiu Analog , tn hiu to ra l batn hiu Video R(), G(xanh l), v B(xanh l) v hai xungng b H.syn (xung ng b dng) , V.syn (xung ng bmnh)

Khi khuch i Video :Tn hiu t Card Video a sang theo 3 ng R, G , B c bin rt yu khong 0,2V c hai tng khuch i tn hiuVideo khuch i ln bin mnh khong 40V trc khia vo iu khin dng pht x t cc Katt .

Khi Vi xl ( CPU )L khi c nhim viu khin thay i tn s dng mnh,thay i kch thc mn hnh, thay i sng, tng phnng thi to ra hin th trn mn hnh .

Bn a tr chut vo hnh xem ch thch

Bn trong Monitor

Bn a tr chut vo hnh chp xem ch thch

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3/96

Vmch Monitor Samsung Synmaster

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4/96

Chng II - n hnh mu

1. Cu to v nguyn l hot ng ca n hnh mu Monitor .

n hnh mu Monitor

Cc Ant : c cung cp khong 15KV ly t dy HV cuncao p, mt in p ny => mn hnh mt nh sng .

Li G1c cung cp khong -30V, khi ta chnh sngin p ny thay i t -20V n -40V, in p G1 cng m thmn nh cng ti , khi tt my G1 c mch dp im snga vo in p -150V dp im sng trn mn hnh .

Li G2c cung cp in p khong 400V ly t trit pScreen trn thn cun cao p, chnh tha in p G2 th mnnh s qu sng v c tia qut ngc, chnh thiu G2 th mnnh ti hoc mt nh sng .

Li G3c cung cp khong 5KV ly t trit p Pocus trnthn cun cao p, chnh sai in p Pocus th hnh nh s bnho, khi hng n hnh s lm in p Pocus b d in dn

n nho hnh

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5/96

Trit p Pocus chnh in p cung cp cho li G3Trit p Screen chnh in p cung cp cho li G2

3 Katt : c phn cc bng in p DC khong 40 n50V , ban u in p 3 Katot bng nhau to ra pht xcn bng trn 3 tia, khi tn hiu R, G, B c a vo 3 Katot,dng pht x trn 3 tia c cng thay i theo bin tnhiu => to thnh cc im nh c mu sc khc nhau trn mnhnh .+ Nu mt Katot no mt kh nng pht x th mn hnh smt mt mu v cc mu khc s b sai .+ in p trn Katot tng th pht x gim, ngc li in ptrn Katot gim th pht x tng, nu mt in p phn cccho 3 Katot th pht x tng cc i => dn n mn nhsng trng v c tia qut ngc .

Si t : c cung cp 6,3V DC , si t c nhim v nungnng 3 Katot cho cc tia in t pht x khi b mt Katot ,mt in p si t hay si t bt th mn hnh s mt nhsng .

Nam chm Purity : C 3 cp nam chm purity nh hng cho3 tia in tp ng vo cc im mu tng ng, cc namchm ny do nh sn xut chnh ( Thkhng chnh) nu bnchnh sai nh s c vin mu .

Cun li tia : Bao gm mt cun li ngang v mt cun li

dc, nu ta rt rc cun li tia ra th mn hnh ch cn mt msng gia mn hnh , m sng ny c tht chy lpPhospho .

B mt n hnh : B mt n hnh c cu to bi cc imPhosspho c kh nng pht ra cc mu (Red), Xanh l cy(Green) v Xanh da tri (Blue), dng tia in t pht x t ccKatot sp vo cc im mu tng ng, pha sau mn hn( bn trong) cch mn hnh khong 1cm l mn chn c l, c3 im mu cho ta mt im nh v mi im nh c mt lnh trn mn chn , mc ch ca mn chn ngn cc tiain t khng bn vo cc im mu sai v tr .

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6/96

2. iu kin mn hnh pht sng

Cao p hot ng bnh thng+ C in p HV+ C in p G2+ C in p G3

C in p si t

Chnh lch gia Katt v G1 khng qu 100V

n hinh tt .

=> V vy khi Monitor khng c mn sng l do mt trong ccnguyn nhn trn .

3. Nguyn l trn mu .

Trong t nhin c ba mu sc c tnh cht .+ Bt k mu sc no cng c th phn tch thnh ba mu sc+ T ba mu sc c th tng hp thnh mt mu bt k=> Ba mu l (Red) , Xanh l (Green) , Xanh l(Blue)

Trong truyn hnh mu, my vi tnh v in thoi di ng ngita s dng 3 mu sc trn truyn i hoc lu tr cc hnhnh mu

n hnh mu thc cht l ba chic n hnh n sc c chungmn hnh v cc li G1, G2, G3, cc Ant, 3 hnh nh pht ra

t 3 Katt chng kht ln nhau v cho ta cm nhn c mt

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7/96

hnh nh vi hng triu mu sc . Nu nh mt i mt ngun tn hiu hay mt Katt no b

hng th hnh nh s mt i mt mu cbn v cc mu khc sb sai .=> Ti v tr c 3 mu => cho ta mu trng=> V tr thiu mu => mn hnh ng mu xanh=> V tr thiu mu xanh l => mn hnh ng mu tm=> V tr thiu mu xanh l=> mn hnh ng mu vng

4. n hnh bnh la trong cn hnh .

ui n hnh

Nu bn bt my ln m nhn thy tia la xanh trong cnhnh( v tr mi tn ) l n hnh bnh la , trng hp ny bnphi thay n hnh .

Nguyn nhn dn n hin tng trn l do li ngun hay limch Regu lm cho in p B+ cp cho cao p tng cao, khi p HV qu mnh gy nh la n hnh .

5. My c cao p nhng mn hnh khng sng .

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8/96

My chy nhng mn hnh khng sng

Khi thy mn hnh khng sng mc d c n bo ngun thbn cn kim tra cc chin p cung cp cho n hnh, bncn kim tra cc iu kin sau :=> Kim tra in p G2 ( o vui n hnh ) nu nhinp ny vn c khong 400V ( o ng h s ) hoc trn 200V( nu o ng h c) th cao p vn ang chy .=> Kim tra in p cung cp cho si t nu c khong 6VDC hoc nhn thy si t sng trong cn hnh l mchsi t bnh thng .=> o gia 3 Katt v G1 nu in p chnh lch khng qu100V DC ( que vo Katt que en vo G1 ) th c Katt vG1 bnh thng, nu chnh lch trn 100V th cn kim tra lip G1, in p G1 khong -30V l bnh thng ( khi o G1 ta que xung Mass, que en vo G1 o thang DCV )=>=> Sau khi kim tra ba yu t trn m vn bnh thng,bn hy tng G2 cao ln hoc chp chn G1 xung Mass nun hnh vn khng sng th do hng n hnh .

6. n hnh b lch tia, hng mt tia .

Biu hin ca n hnh lch tia l b mt mt mu v sai mu

n hnh mt mu xanh l (G )

Trng hp trn c 3 nguyn nhn+ Hng KG ca n hnh+ in p phn cc cho KG tng+ Mt tn hiu G i ti Katot

kim tra n hnh bn lm nh sau :

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9/96

=> Dng in trkhong 1K 1W u tt t KG xung massv quan st mn hnh .=>> Nu mn hnh sng rc v mu xanh l th KG n hnhvn tt, h hng thuc v 2 nguyn nhn cn li .=>> Nu mn hnh t thay i th n hnh b hng KG

Trng hp trn bn hy chnh li 3 trit p Bias trn vuin hnh, nu khng c kt qu th bn cn phi thay n hnh .

7 . n hnh b gi :

n hnh gi thng gp cc my c thi gian s dng lunm biu hin l hnh nh mv ti .

nh mv ti, biu hin ca n hnh gi.

Trng hp trn khng ch do n hnh m cn c th do mchkhuch i tn hiu Video , kim tra n hnh bn lm nhsau :

kim tra n hnh bn lm nh sau :=> Dng in trkhong 1K 1W u tt ln lt KR, KGv KB xung mass v quan st mn hnh .=>> Nu mn hnh sng rc v cc mu th n hnh vn tt, hhng thuc v nguyn nhn cn li .=>> Nu mn hnh t thay i th n hnh b km c 3 tia .

Khc phc tnh trng trn bng cch=> Tng in p si t ln khong 1 => 2V

=> Tng in p B+ cp cho cao p ( chnh nm HV.ADJ trongmy )=>> Cc bin php trn ch l gii php tnh th .

8. n hnh b x li - nhim t.

Mt s trng hp my b nhim t nng nh hnh cu vngan vo nhau .

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10/96

My b nhim thnh cu vng

Nguyn nhn ca hin tng trn l do n hnh b x li do

my b va chm qu mnh , mn chn c l ngay sau mnhnh b x i v gy hin tng trn . Vi hin tng trn th bn ch c thay hnh mi m thi .

9. Cc bnh do sai in p li .

9.1 Chnh tha in p li G2 hoc mt in p m trn G1

Mn nh sng trng c tia qut ngc

Hin tng trn l do tha in p li G2 hoc mt in pm trn G1 sinh ra nh m, mn qu sng v c tia qut ngc .

Khc phc : khc phc hin tng trn bn cn kim tra inp trn li G1, in p G1 phi c in p m t -20V n -40V nu mt ngun m trn G1 th thng km theo hin tngc m sng khi tt my .

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11/96

C m sng khi tt my do mt ngun m trn G1

Nu in p m trn G1 bnh thng th bn chnh li trit pG2 ( trit p Screen ) nu chnh khng c tc dng l do hngtrit p ny .

9 .2 Sai in p Pocus ( G3 )

Nu in p Pocus b sai , cao qu hay thp qu u dn nhin tng nh b nho nhn khng r cc chi tit .

nh b nho do sai in p Pocus

Hin tng trn thng do hai nguyn nhn+ Hng n hnh gy d in Pocus=> Vi trng hp ny th hnh nh ban u nho sau r dn

n hnh mu trng gn vo cn hnh

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12/96

+ Hng trit p Pocus trn thn cun cao p=> Vi trng hp ny th hnh nh ban u r sau nho dn

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13/96

Chng III - Khi ngun

1. S khi tng qut ca b ngun

Bn a tr chut vo sxem ch thch

S tng qut ca b ngun Monitor

2. Mch lc nhiu, chnh lu v kht:


Mch u vo ca ngun Monitor

Mch lc nhiu bao gm cc linh kin

C1, C2 v cun dy L1

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14/96

Cun dy lc nhiu

Mch kh t gm c in trThemsistor ( T.H ) v cun dy

kh t Degauss qun quanh n hnh . in trhn dng R1 l in trs khong 2 10W c nhim

v hn ch dng in np vo t, trong trng hp ngun bchp th R1 ng vai tr nh mt cu ch .

Cc it D1 - D4 chnh lu dng in xoay chiu thnh dngmt chiu, t lc C3 s lc cho in p mt chiu bng phngcung cp cho ngun xung hot ng .

Mch lc nhiu, chnh lu v kh t ca cc my Monitor l nhnhau

v c s mch nh trn

Khi mt ngun 300VDC trntreenlocj ngun chnh th ta cn kimtra cc linh kin trn

3. Ngun Switching ( Ngun ngt m)

Phn ngun Switching thng s dng mt trong hai kiu sau :

Ngun c hi tip t cao p Ngun c hi tip so quang

Sau y ta s xt cc trng hp c th

3. 1. Ngun c hi tip cao p


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15/96

Ngun c hi tip cao p

B ngun c cc thnh phn chnh nhsau :

Mch to dao ng :B ngun Monitor thng s dng cp linh kin l IC to

dao ng kt hp vi Mosfet ng mto thnh dng inxoay chiu tn s cao a vo bin p xung .

IC dao ng a s s dng IC - KA3842 y l IC rt thngdng v gi thnh r .

KA3842 - IC dao ng ngun trong MonitorCc chn ca IC ny nh sau :+ Chn 1 : l chn nhn hi tip iu khin p ra, in pchn 1 t l thun vi p ra , ngha l nu p chn 1 tng thin p ra tng+ Chn 2 : ngc vi chn 1 tc l in p chn 2 tng th inp ra gim .+ Chn 3 : l chn bo v , khi in p chn 3 > 0,6V th IC sct dao ng bo vn cng sut ngun khi b chp phti .+ Chn 4 : l chn dao ng , khi ngun ang hot ng bntrnh o vo chn 4 v php o s lm sai tn s dao ng gy

hng s cng sut, tn s dao ng ph thuc R, C bm vo

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16/96

chn 4+ Chn 5 : u mass+ Chn 6 : l chn dao ng ra, in p xung dao ng o cti chn ny khong 2VDC hoc 4VAC ( VAC l o bngthang AC)+ Chn 7 : l chn cp ngun cho IC , chn ny phi c 12VDCn 14VDC th IC mi dao ng , in p chn ny c cung

cp t ngung 300VDC gim p qua trmi 47K v c mchhi tip n nh ngun nui .+ Chn 8 : l chn i ra in p chun 5V cung cp cho mchdao ng .

Mch cng sut :Cng sut ngun i vi IC l n Mosfet , thng thng sdng n K... , 2SK...

Mosfet l linh kin c trkhng chn G l v cng v vychng rt nhy vi cc ngun tn hiu yu, trong mch nuMosfet b hchn th chng s b hng ngay lp tc .in p dao ng t chn 6 IC dao ng c a vo chn

G ca Mosfet iu khin cho Mosfet ng m, trong cctrng hp IC dao ng h lm cho p dao ng ra dng mtchiu cng ln hng Mosfet .

Mch hi tip n nh p ra :L ton b mch mu tm s trn, chng c nhim vhi tip gi cnh in p ra trong trng hp in p vothay i .

Mch hi tip cao p :Trong hai trng hp cao p hot ng v khng hot ng,

ngun c s thay i ln v dng tiu th, do s st p trncun hi tip t hn so vi cun th cp khi cao p chy, vvy vng hi tip trn khng gic in p ra cnh, vvy ngi ta khc phc bng cch a xung dng hi tip vchn 4 ca IC dao ng

Khi c xung dng hi tip v chn 4 th in p ra khng cnb st p khi cao p chy . ( cao p tiu th 70% cng sutngun)

Mch bo v :Khi cc ph ti tiu thu in ca ngun b chp => dn n ncng sut hot ng qu ti v hng , bo vn cng sutngi ta u t chn S n cng sut xung mass qua in tr0,22 v ly st p trn in trny a v chn bo v ca ICdao ng, khi n cng sut hot ng mnh, sut p trn intrny tng => in p a v chn bo v tng => ngt daong .

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17/96

S nguyn l ngun Monitor

Nguyn l hot ng :

Khi bt cng tc ngun, trn t C1 c 300V DC in p ny iqua R1(mi) vo cp ngun cho chn 7 IC dao ng, IC hotng v to ra dao ng chn 6 a sang chn G iu khinMosfet Q1 ng m=> to thnh dng in bin thin chyqua cun 1-2 bin p xung, dng in ny to thnh t trngbin thin cm ng ln cun hi tip 3 - 4 v cc cun th cp .

Cu phn p R8, VR1, R9 trch ly mt phn in p hi tiplm p ly mu a v chn 2 iu khin in p ra .+ Gi s khi U vo tng => U ra c xu hng tng => p hitip cng tng => in p a v chn 2 tng => IC siuchnh cho bin dao ng ra gim => kt qu l in p ragim v v tr c

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18/96

+ Nu ban u in p U vo gim th qu trnh ngc li .=> kt qu l in p ra lun c gia cnh .

Khi cao p chy , dng tiu th tng cao , in p ra c xuhng st p v mch hi tip trn khng b li 100% , vvy vng dy qun quanh cao p => i qua R10, D6, C2 vchn 4 ca IC s lm nhim v gi cho in p ra khng b stp .

Khi mt trong cc ng ph ti b chp, n cng sut Q1hot ng mnh, st p trn R6 tng ln, st p ny i qua R5

v chn 3 IC ngt dao ng => sau mch hi li v li bbo v => kt qu l in p b t kch, n bo ngun chpchp .

4 . Ngun c hi tip so quang


Ngun c hi tip so quang

B ngun c hi tip so quang tng t ngun hi tip cao p,

ch thay i mch hi tip v chn s 2 ca IC dao ng, in

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19/96

p hi tip bt ngun tin p B1 ( bn th cp - ngun cpcho cao p) hi tip v thng qua IC to p d sai KA431 v ICso quang .

Mch hi tip so quang

Nguyn l hot ng n p :Gi s khi in p vo gim hoc khi cao p chy dng tiu thtng=> in p ra c xu hng gim=> in p chn 1 IC : KA431 gim=> Dng in i t chn 3 qua n Q1 qua Dz v chn 2 trong

IC : KA431 gim=> Dng in qua Diode D2 trong IC so quang gim=> Dng in i qua n Q2 trong IC so quang gim=> in p v chn s 2 IC : KA3842 gim=> Bin dao ng ra t IC tng => n cng sut hot ng

mnh hn=> Kt qu lm in p ra tng v v tr c .

Mch hi tip so quang gi cho in p ra khng thay i

trong c hai trng hp :+ in p vo thay i v+ Dng tiu th thay iV vy mch hi tip ny khng cn ti vng hi tip t cao pna

5. Ngun sdng IC cng sut

Thc cht IC cng sut = ( IC dao ng + Mosfet )

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20/96

Ngun Monitor sdng IC cng sut

IC cng sut thc cht l c tch hp mch dao ng vi nMosfet trong mt linh kin duy nht, v vy IC cng sutthng c cc chn nh sau :+ Chn Vcc cho mch dao ng , s trn l chn s 2+ Chn i vo cun scp bin p ( chn 1) chn ny si vochn D n cng sut .+ Chn tip Mass ( chn 2 )+ Chn nhn hi tip giin p ra cnh ( chn 4 )+ Chn nhn hi tip cao p ( chn 5 )

Nguyn l hot ng :Khi bt cng tc ngun, in p 300VDC i qua trmi R1vo cp ngun cho mch dao ng chn 3, IC hot ng viu khin v dng in qua cun scp bin thin tn scao, dng in ny tao thnh t trng cm ng ln cc cunth cp v cun hi tip .+ in p hi tip c chnh lu thnh DC quay li n nhngun nui cho chn Vcc+ Mch hi tip ly mu tin p ra B1 thng qua cu phnp a vo chn 1 IC d sai KA431 , IC d sai khuch i inp ly mu to thnh dng in hi tip a qua IC so quangv chn s 4, in p chn 4 IC ny t l thun vi in p ra .

=>> Gi s khi in p ra tng => in p ly mu tng =>

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21/96

Cc bnh thng gp ca khi ngun

dng qua IC so quang tng => in p chn 4 gim => kt qul in p ra gim xung v v tr c .++ Nu mt l do no lm mt hi tip t mch so quang thin p ra s tng cao, IC cng sut hot ng qu ti v c thb hng .+ Mch hi tip t cao p v ngun thng qua bin p cch lyc hai tc dng

- Tng cng n nh in p ra khi cao p chy- Bo v ngt dao ng ngun nu cao p b chp .

- Trong trng hp cao p b chp th ngun hot ng trongvi giy ri ngt .


nh chp b ngun Monitor Samsung Synmastersdng IC cng sut

Bnh 1 : Khng c n bo ngun, khng c in p ra .

Bt cng tc khng c n bo ngun

Nguyn nhn : hin tng trn l do mt trong 2 nguyn nhnsau :

Chp n Mosfet hoc IC cng sut, n cu ch, mt ngun

300V

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22/96

Cn 300V trn t lc ngun chnh, mt dao ng, n cngsut khng hot ng .

Kim tra :

Quan st :Bn cu ch ? nu cu ch n chy en l biu hin cachp n cng sut ( hoc IC cng sut )Nu cu ch khng t l biu hin cng sut khng b chp,ngun b mt dao ng .

o kim tra trkhng :+ Ch trc khi o cn thot in trn t phng inp d lm hng ng h, bn dng m hn thot in, khngc chp trc tip .+ Chuyn ng h v thang x1 o vo hai u t lc ngun,o chiu que o hai ln v xem kt qu .

Php o cho thy trkhng bnh thng

Nu o thy trkhng bnh thng .+ o vo hai u t lc ngun, o que o hai chiu, nu ktqu mt chiu o kim khng ln, mt chiu o kim ln nhtrn l trkhng bnh thng .=> Trkhng bnh thng ( ngha l n cng sut s khnghng )

=> Nu n cng sut khng hng th do mt trong cc nguynnhn sau :- in trmi t- i t zener gim chn Vcc ( nu c ) b chp- Lng chn IC dao ng- Hng IC dao ng .

Nu o thy trkhng b chp .+ l trng hp bn o vo hai u t lc ngun thy c haichiu o kim ln = 0 .+> Trkhng chp l do chp Mosfet hoc IC cng sut=> Vi trng hp ny thng ko theo n cu ch v hng cu

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23/96

Diode chnh lu u vo, hng cc in trxung quanh nMosfet

Cc bc sa cha

a ) Ngun dng IC dao ng & Mosfet bn sa cha nhsau


Trng hp : n cng sut khng b chp, ngun b mt daong .

Tm thi tho n Mosfet ra ngoi Cp ngun v kim tra cc chin p sau :

o trn t lc xem c 300VDC cha ?=> Nu cha c th cn xem li cu ch, cu Diode v in trs hn dng

o chn Vcc cho IC dao ng xem c 12V khng ?=> Nu khng c th cn xem li in trmi hoc mch cpngun cho chn Vcc, nu mch tt th thay IC dao ng .

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24/96

Nu c Vcc12V chn 7 th o ti chn G xem c dao ngkhng ?=> Nu o thy khong 2VDC hoc 4VAC v kim dao ng

nh hnh di => l ngun c dao ng ra .

Nu khng thy dao ng ra nh trn th bn thay IC dao ng. Ch khi no c dao ng ra nh trn bn mi lp Mosfet vo

Ch : Khi hn Mosfet bn phi thot ht in trn t, nu cntch in trn t th c th lm hng Mosfet trong lc bn ang

hn chn => Nu c dao ng m lp Mosfet ngun vn khng chy

th cn kim tra cc ph ti xem c b chp khng ? o kim traph ti bng thang x1 trn cc t lc u ra .

Trng hp : Ngun b chp cng sut, n cu ch .

Nguyn nhn h hmg l do :- Do lng chn n cng sut- Do chp ph ti

=> Khi ngun chp cng sut thng ko theo > N cu ch,

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25/96

chpcc Diode chnh lu, hng IC dao ng, t cc in tr

xungquanh Mosfet , v vy bn cn thc hin theo cc bc sau :

Tho Mosfet ra khi ngun Thay cu ch, thay cc Diode, R s nu thy hng . Cp ngun v kim tra xem c 300VDC trn t lc ngun

chnh cha ? sau nhthot in tch trn t .

Kim tra v thay cc in trxung quanh Mosfet nh R4, R5,R6 nu hng .

Thay IC dao ng mi KA3842 o ti chn G xem c dao ng ra cha ?

Nu o chn G thy c khong 2VDC hoc 4VAC v kim daong nh trn l IC dao ng .

Nu khng c dao ng ra th bn cn kim tra li chn Vcc (7)xem c 12V khng ?

Ch khi no c dao ng ra nh trn bn mi lp Mosfet voCh : Khi hn Mosfet bn phi thot ht in trn t, nu cntch in trn t th c th lm hng Mosfet trong lc bn ang

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XUANVINH


26/96

hn chn => Nu c dao ng m lp Mosfet ngun vn khng chy

th cn kim tra cc ph ti xem c b chp khng ? o kim traph ti bng thang x1 trn cc t lc u ra .

b ) Cc bc sa cha vi ngun sdng IC cng sut


Trng hp : IC ngun khng chp nhng ngun khng daong,

khng c in p ra

Nguyn nhn h hng :

Trong cc trng hp cn in p 300VDC u vo nhngkhng c in p ra th thng thng IC cng sut khng hng,nguyn nhn thng do mt ngun Vcc vo chn cp ngun12V cho mch dao ng, chn ny cn c in p t 12V n15V .

Hng IC so quang lm mt in p chn s (4) => mt in pra Mt s t trng hp do hng IC .

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XUANVINH


27/96

Kim tra & sa cha :

Kim tra in p chn Vcc (3) ca IC cng sut, nu in pchn ny < 12V th bn cn kim tra R mi (R1) v c bit lu Diode Zeneru t chn (3) xung mass rt hay b d .

Nu chn Vcc c in p th bn hy thay th IC so quang . Vn khng c kt qu th bn cn thay IC cng sut mi .

Lu : Vi cc my s dng IC cng sut ngun nh SamsungVina,

LG , bn lu trng hp hng cao p cng lm cho ngun mtdao ng do cc my ny s dng chn hi tip (5) bo vngun , v vy khi khng tm thy h hng bn scp th bn

cnkim tra cao p.

Trng hp : Chp IC cng sut ngun, n cu ch .

Nguyn nhn h hng- Do mt hi tip so quang- Do chp ph ti- Do in p u vo qu cao

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XUANVINH


28/96

Cc bc sa cha :

Tho IC b chp ra ngoi Kim tra v thay th cu ch, cu Diode, in trs nu hng

sau cp in v kim tra in p 300VDC Kim tra k cc linh kin ca mch hi tip so quang ( nu c ) Kim tra k cc ph ti ra ca ngun xem c ph ti no b

chp khng ? Lp IC mi vo ngun . Cp in , bt cng tc sau 3 giy ri tt ngay, quan st n bo

ngun .=> Nu c n bo ngun l biu hin ngun hot ng=> Nu khng c n bo th cn kim tra li ton b xem cnlinh

kin no h hng m cha pht hin ra .=> Nu li hng IC v n cu ch th bn cn thay ton b cclinh

kin ca mch hi tip so quang .

Bnh 2 : in p ra thp v tkch, n bo ngun chp chp

Nguyn nhn :

Ngun b chp ph ti thng thng hay b chp ng B1 cpcho cao p ( do chp s cng sut dng ) .

Hng mch hi tip so quang

Phn tch :

Khi ngun c in p ra l chng t+ c ngun 300V DC vo+ IC dao ng hot ng+ n cng sut vn tt

in p ra thp l biu hin ca chp ph ti hoc hi tip soquang a v qu mnh hoc qu yu dn n in p ra b tkch ( c - mt - c - mt : gi l t kch )

Kim tra & sa cha :

Vi phn tch trn bn nn kim tra k cc ph ti :

- Kim tra ng B1 xem c chp khng ?

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XUANVINH


29/96

- Kim tra s cng sut dng xem c chp khng ?- Kim tra cc ng ti ra khc ca ngun( Kim tra ph ti bng thang x1 que vo mass my, queen vo cc dng t lc u ra => nu trkhng cao l bnhthng, trkhng thp ( vi chc trxung l b chp )Lu : c mt ng in p cp cho si t c trkhng rtthp, bn c th tm tho vui n ra khi kim tra .

Nu khng pht hin thy chp ph ti => th nguyn nhn ldo mch hi tip so quang c vn .

IC so quang 4 chn IC so quang 6 chn

Bn cn thay th IC so quang v IC to p d sai KA431 nunh sau khi kim tra cc ph ti khng thy b chp .

Nu kim tra thy chp s dng th bn cn kim tra cun caop :

Kim tra cao p : thang 1K hoc 10K o gia dy HV ( o t nm cao

p) vi Mass my th trkhng phi bng v cng ( kim khngln)- Nu kim ng h ln mt cht l cao p b d t ABL bntrong co p

- Nu kim ng h ln = 0 l chp t ABL trong cao p

>> C hai trng hp h hng trn u c th sa c cao p,bn phi tho cun cao p mang n hiu chuyn sa cao p thay t ABL .

Lu : Bin p xung ca b ngun khng bao gihng ( tr cctrng hp c bit nh nc vo )

Bin p xung trong b ngun

V vy trong cc trng hp tm cha ra bnh bn ng nghi ng

hng bin p xung, v iu ch lm cho bn mt thi gian .

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XUANVINH


30/96

Chng IV - Khi qut dng

1. Nhim v ca khi qut dng .

Khi qut dng c nhim v cung cp cc mc in p cho nhnh hot ng bao gm :- in p HV ( High Voll - Cao p ) khong 15KV cung cpcho cc Anot .- in p Pocus ( p hi t ) khong 5KV cung cp cho liG3- in p Screen khong 400V cung cp cho li gia tc- in p -150V cung cp cho mch Bright phn cc choG1

Cung cp xung dng cho cun li tia ( cun li dng ) dnmn hnh theo chiu ngang .

2. Cc thnh phn chnh ca khi qut dng :


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XUANVINH


31/96

S khi qut dng

Mch to dao ng H.OSC :- Mch to dao ng c nhim v to ra xung dng iukhin n cng sut dng ng m=> iu khin cao p hotng .

Tng kch dng H.Drive ( Q1 ):- Tng kch dng khuch i xung dng cho mnh trc khi

a n chn B n cng sut dng . Tng cng sut H.OUT ( Q2 )

- Tng cng sut hot ng nh mt cng tc ng mdi siu khin ca dao ng => to thnh dng in bin thin tn s cao chy qua cun scp cao p .

Cao p- L bin p hot ng tn s cao to ra cc mc in p caocung cp cho n hnh

Mch Regu ( n p ng B+ )- C nhim viu chnh in p cung cp cho cao p .

Mch cng tc :

- Mch c nhim viu khin in p cung cp cho mch daong dng thng qua lnh Stanby .

3. c im ca khi qut dng Monitor

Tn s dao ng :- Tn s dao ng dng ca Monitor thay i t 31,5KHz n70KHz tu theo phn gii m chng trnh phn mm ara .- Trong Windows XP bn c th thay i ti 10 phn giikhc nhau, khi ta thay i phn gii thng qua xung H.synsiu khin cho tn s dng thay i theo.

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XUANVINH


32/96

- Di y l bng th hin mi quan h gia phn gii vitn s qut dng .

in p cp cho cao p :- Khi tn s qut dng tng => trkhng cun scp tng ln=> dng in qua cun scp cao p gim => kt qu l inp HV gim xung => sinh ra hin tng mn nh ti v cohnh .

Nguyn tc hotng ca n cng sut dng

- khc phc tnh trng trn ngi ta rp thm mch Regu thay i p B+ sao cho khi tn s dng tng => mch Regu ara p B+ tng, ngc li khi tn s dng gim => mch Regucng a ra p B+ gim => Mc ch gi cho in p HVkhng i- C hai loi mch Regu l mch Regu tng p v Regu hp

- Vi mch Regu tng p th p B1 i vo khong 50V, p B+ra thay i t 70V n 120V- Vi mch Regu h p th p B1 i vo khong 180V, in pB+ ra khong 90V n 140V .

4. Nguyn l hot ng ca khi qut dng.


phn gii Tn s H.syn Tn s qut dng640 x 480 31,5KHz 31,5KHz

800 x 600 37,8KHz 37,8KHz

1024 x 768 48,4KHz 48,4KHz

... ... ...

1280 x 1024 63,9KHz 63,9KHz

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XUANVINH


33/96

S khi qut dng

Khi bt cng tc ngun => Ngun cho ra cc in p B1(50V)cung cp cho cao p, p B3(24V) cung cp cho tng kch dngv B4(12V) cung cp cho mch dao ng .- in p B1 qua mch Regu thay i thnh B+ sau avo cun scp cao p chti chn C s dng (Q2) .- in p 24V i ti cp ngun cho tng kch dng ( chtichn C n Q1).- in p 12V chti mch cng tc ( Q4 v Q5 )

Khi c tn hiu H.syn ( khi ta bt Case my tnh ) tn hiu H.syni qua cp tn hiu a vo IC vi x l (CPU) => Khi cH.syn , vi x l cho ra lnh Stanby (5V) => iu khin ngmch cng tc Q4 & Q5 => a 12V vo cp ngun cho mchdao ng dng H.OSC .

Khi H.OSC c cp ngun => to ra dao ng a nkhuch i qua tng kch dng Q1 => sau ghp qua bin pkch T1 sang iu khin cho n cng sut Q2 hot ng .

n cng sut Q2 hot ng ng mnh mt cng tc to

thnh dng in bin thin chy qua scp cao p => cm ngln cc cun th cp => cho ra cc mc in p cao a lnphn cc cho n hnh hot ng .

Khi ta thay i chng trnh ng dng c phn gii khcnhau => Card Video a ra tn s H.syn khc nhau => thngqua CPU iu khin cho tn s dng thay i- Khi tn s dng tng => p HV gim- Khi tn s dng gim => p HV tng gi cho in p HV khng i , ngi ta thit k mchRegu vi mc ch iu chnh li p B+ cp cho cao p => t gic in p HV cp cho n hnh lun lun n nh .- Khi tn s dng tng => Mch Regu iu khin cho p B+

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XUANVINH


34/96

tng- Khi tn s dng gim => Mch Regu iu khin cho p B+gim=> Kt qu l p HV khng i

5. Mch Regu ( Mch n p ng B+ )

Nhim v chnh ca mch Regu l iu chnh in p B+ cungcp cho cao p khi tn s dng thay i , c 2 loi mch Reguthng c s dng trn thc t, sau y ta s xt tng mchc th .

5.1 Mch Regu nng p ( Boost )


S mch Regu nng p ( Boost )

Ngun 50V ly ra t ngun sau khi chnh lu v lc thnh inp mt chiu (B1) c a qua cun dy L1 sau cho ngmxung Mass qua n cng sut Q1 to thnh in p

dng xung c bin > B1 , sau in p ny c chnh luv lc thng qua D2 v C2 to thnh in p mt chiu B+ avo cao p .

in p B+ thu c c gi tr cao hn in p B1, gi tr B+ph thuc vo mc hot ng ca n cng sut Q1, nu Q1khng hot ng th B+ = B1, khi Q1 hot ng cng mnh thp B+ cng tng, mc ti a B+ c th tng gp 5-6 ln p B1.

Ngi ta siu khin mc hot ng ca n Q1 bngcch iu khin bin xung dao ng ra t IC : OSC thngqua lnh t CPU, khi tn s H.syn tng => thng qua CPU iukhin cho bin xung dao ng tng => Q1 hot ng tng=> p B+ tng , in p B+ c khng ch trong phm vi t

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XUANVINH


35/96

70V n 120V v tng t l thun vi tn s qut dng . Mch OSC c nhim v to ra dao ng a n iu khinn cng sut Q1 ng m, dao ng to ra c khuch im qua hai n Q2 v Q3 trc khi a vo chn G nMosfet Q1, mch OSC c th l mt IC c lp nhng thngthng c tch hp chung vi IC dao ng dng mnh .

Mch hi tip t cao p v qua R2, D3 v trit p HV.ADJ cnhim v gi cho in p B+ n nh khi dng tiu th ca caop thay i, in p hi tip ny t l nghch vi p B+ .

- Khi dng tiu th ca cao p tng => B+ st p => in pHV v p hi tip c xu hng gim => thng qua mch hitip a v IC iu chnh cho bin dao ng ra tng => ktqu l p B+ tng v v tr c .

=> Trng hp mt hi tip t cao p v mch Regu => s dnn in p B+ tng cao lm hng n cng sut dng v c thgy nguy him cho n hnh .

Trit p HV.ADJ c thit k thay i in p B+ khong10% (dnh cho thchnh), nu trit p ny tip xc km cngl mt nguyn nhn gy hng s dng .

5.2 Mch Regu h p


S mch Regu h p

Mch Regu h p c mch dao ng, mch hi tip, mch iukhin tng t nh Regu nng p .

Mch cng sut ca Regu h p c thit k vi n cng sutl Mosfet thun, t ngun B1 i qua n Mosfet trc sau mi i n cun dy v sau cun dy l in p B+ cp cho caop, n Mosfet v cun dy c mc ni tip .

in p B1 khong 180V khi qua mch Regu c h xung

in p B+ t 90 n 140V tu theo phn gii .

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XUANVINH


36/96

6. Phn tch khi qut dng Monitor SAMSUNG 753DFX

Bn hy tm mua quyn sch sau chNht to TP H ChMinh hoc chTri H Ni

Lt n trang S SAMSUNG 753 DFX .


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XUANVINH


37/96

Khi qut dng Monitor Samsung 753DFX

Mch qut dng v cao p my SAMSUNG 753DFX :- IC dao ng c tch hp mch dao ng dng H.OSC v daong Regu vo lm mt, IC c cp ngun 12V i vo chn29- Mch dao ng dng H.OSC to ra xung dng ra chn 26i qua C414 qua R426 vo khuch i qua tng kch dngQ403 sau ghp qua bin p T401 a sang chn B n cngsut dng Q404, xung dao ng siu khin cho n cngsut ng mnh mt cng tc in t => to thnh dng inbin thin chy qua scp cao p => cm ng ln cc cun th

cp cho ra cc in p cao .- in p AFC a v qua R511 qua R501 v chn 12 IC daong c nhim v gin nh tn s dao ng dng .

Mch Regu v p B+- T bin p ngun ng 50V c chnh lu v lc thngqua D609 v C407 ( p B1) , p B1 i qua L402 n chn Dn Mosfet Q402, khi Q402 hot ng ng m=> sinh ra inp cm ng chn D c bin ln, in p cm ng ny cchnh lu v lc thng qua D401 v C409 to thnh in pB+ , p B+ thu c > B1- OSC l mch to dao ng iu khin Mofet ca Regu hotng, dao ng ra chn 28 khuch i m qua hai n Q401v Q420 sau a qua R vo chn G n Mosfet Q402 iu khin n ny hot ng .- Mch bo v qu ti : Khi Q402 hot ng qu ti => st ptrn R413 tng => st p ny a qua R412 v chn 16 IC ngt dao ng ra nhn 28 .- Mch hi tip t chn AFC cao p c chnh lu qua D501,C505 thnh p DC sau a qua cu phn p R506, R505 quaR504 v chn 15 IC dao ng c tc dng gi cho in p B+n nh khi dng tiu th ca cao p thay i .Lu : khi ng hi tip ny hng => mt hi tip v chn

15 => in p B+ s tng cao lm hng s cng sut dng vc th gy nguy him cho n hnh .

Nhn bit cc khi chnh ca Monitor

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XUANVINH


38/96

Chi tit v cc linh kin trn Monitor

Bn a tr chut vo nh chp xem ch thchPhng php nhn bit linh kin

Vmy Monitor Samssung

7. Phng php d mch qut dng .

Vi cc bn mi vo ngh hoc mi tip xc vi Monitor ththng gp kh khn khi d mch ca mt khi , sau y lminh ho phng php d mch ca khi qut dng .

Bt k mt kh no cng c nhng linh kin d nhn bit cho talm mc t tm ra tt c cc linh kin, vi khi qut dng

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XUANVINH


39/96

bn hy bt u t cao p .

8. Phng php d mch Regu

Bn cng bt u t cao p, thng thng in p B+ i vo

chn s 2 hoc bn nhn chn no c Diode i vo v t lc th l B+=> d ngc li v pha ngun bn s tm ra cc linh kin camch Regu .

Cc bnh thng gp ca khi qut dng Monitor,phng php kim tra sa cha .

Bnh 1 :

Hin tng :My c n bo chmu vng , khng ln mn sng .

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XUANVINH


40/96

Nguyn nhn :Hin tng trn l do cao p cha hot ng thng thng domt trong cc nguyn nhn sau :- Mt in p B+ cp vo cao p- Hng tng kch dng- Hng vi x l lm mt lnh Stanby iu khin mch cng tccp ngun vo IC dao ng dng .- t cp tn hiu (dy H.syn hoc V.syn) => cng dn nmt lnh iu khin Stanby- Hng IC to dao ng dng mnh .

Phng php kim tra :* o kim tra xem c in p B+ i vo chn cao p khng(in p B+ t50V trln l cao p c thhotng)

V tro p B+

Nu khng c in p B+ bn cn kim tra mch cp ngun tngun B1 => i qua mch Regu

* Ti p theo bn o dao ngchn B s dng xem c 0,6VAC khng ?

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XUANVINH


41/96

V tro kim tra dao ng

Nu o chn B s dng vn c 0,6V th c th cao p anghot ngBn hy => Tng trit p G2 ( Screen trn thn cao p )

=> o p si t chn (HT) n hnh xem c 6,3VDC?=> Kim tra p G1 xem p m c bao nhiu ?( G1 bnh thng c -30V, nu p G1 ln ti m -

120Vs mt nh sng .)

Nu mt dao ng chn B s dng > bn hy >- o chn C n kch dng xem c in p khng ? ( bnhthng im ny c khong 15V )- o Vcc cho IC dao ng xem c 12V DC khng ? (chn Vccchn c t lc to nht cnh IC )- o chn dao ng ra (chn x - d tn kch v ) phi c t2 n 3 VDC => nu chn ny khng c p ra l hng IC

Cc im o ca khi qut dng

=> Nu khng c Vcc i vo IC dao ng th bn cn kim tra :>> Cp tn hiu>> Kim tra mch cng tc cp ngun cho IC>> Kim tra IC vi x l

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XUANVINH


42/96

Kim tra cp tn hiu nhsau :

Dng thang x1 o s thng mch ca hai dy tn hiu H.synv V.syn

V tr ca dy tn hiu H,SYN v V.SYN

Kim tra mch cng tc nhsau :

Nh s di y, hai n cng tc cp ngun vo IC daong l Q4 v Q5 , nu cc n ny hng hay lng chn cnglm mt ngun cung cp cho IC dao ng , hai n ny ciu khin bi lnh Stanby ly t vi x l .

Mch cng tc Q4, Q5 cp ngun cho IC dao ng

Nu mch vi x l khng hot ng th s mt lnh Stanby vkhng

iu khin c hai n cng tc Q4, Q5

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XUANVINH


43/96

Kim tra vi xl nhsau :

o in p Vcc cho vi x l phi c 5V DC

Cc phm bm ( trc my ) khng c d hoc chp

Xung quanh IC vi x l phi kh ro, khng c du hiu ca

m t hay cn trng xm nhp .

Phi c tn hiu H.syn v V.syn i ti

Bnh 2 :

Hin tng :n bo ngun chp chp t kch, ngun c ting rt nh .

n bo ngun tkch - chp chp

Mt s trng hp khng thy n bo nhng khi o in pra sau bin p ngun thy c in nhng t kch, kim dao ng .

o in p AC ra sau bin p xung thyin p ra thp v tkch, kim dao ng

=> l biu hin ca ngun b chp ph ti

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XUANVINH


44/96

Bin p xung ca b ngun

Khi ngun bnh thng bn thy in p ra ngv kim ng yn (o thang AC vo chn bin p )

Nguyn nhn hhng :- Hin tng chp ph ti thng thng do chp s dng hocMosfet ca mch Regu nng p .- Mt s t trng hp l do hng mch hi tip so quang cab ngun cng lm cho ngun t kch .

Lu : Bnh ny thng khng phi hng bn scp ngun,mt s bn khi o p bn scp thy p dao ng thay th

IC, n cng sut v v...=> kt qu l khng ng bnh .

Kim tra :+ Trc ht bn hy kim tra s dng xem c chp khng ?

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XUANVINH


45/96

V tr s cng sut dng gn trn tm

to nhit quanh cao p

ng h thang x1 o gia C v En cng sut dng

Thy mt chiu o kim khng ln

o li thy kim ln qu na thango

=> Kt qu nhtrn l trkhng bnh thng, s dng khnghng

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XUANVINH


46/96

Nu o thy c hai chiu o kim ln bng = 0 => l b chps dng .

Ch >>>=> Nguyn nhn chp s dng l do chp cao p ( 90% )=> Do mt hi tip t cao p v dao ng Regu => dn n p

B+ tng cao ( 10% )

=>>> Cao p b chp thng do chp t ABL trong cao p bnc th kim tra c

o kim tra cao p :

thang 1K hoc 10K o gia nmHV vi Mass my (chiu o bt k )

Nu :- Kim khng ln th => a s l cao p tt ( vn c 10%hng )- Kim ln mt cht => Cao p b hng , d t ABL- Kim ln = 0 => Cao p b chp t ABL

Trng hp cao p b d hay chp t ABL => bn hy tho

cao p ra mang ti thchuyn sa cao p thay t

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XUANVINH


47/96

V tr t ABL trong cao p

- Sau khi sa cao p v lp li my, lp s dng mi vo lmy c th hot ng trli .- Mt s trng hp khi chp cao p => ko theo chy enin trtrn ng ABL (mt tr s) => bn hy thay bng intr33K

Nu cao p khng hng => bn lp s dng vo => Nu nhs dng li hng trli th bn lu => nguyn nhn do pB+ tng cao .=> Bn kim tra kng hi tip t cao p v mch Rugu nhlc di y .


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XUANVINH


48/96


49/96

D mch Regu : Btu tchn B+ Cao p (thng thng lchn s2 tnh theo chiu kim ng h) => n Diode => n

cun dy v n Mosfet => tn Mosfet xc nh c ICdao ng .

Cm cp tn hiu vo my tnh hoc hp Tivi box , cp ngunv bt cng tc Monitor :

Kim tra in p B1 xem c bao nhiu Vol DC ? :

o kim tra in p B1 bng thang 250V DC

Kim tra in p B+ xem c bao nhiu Vol DC

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XUANVINH


50/96

o kim tra in p B+ bng thang 250V DC

So snh hai in p o c t p B1 v B+- Nu B+ = B1 th => Mch Regu khng hot ng .- Nu B+ > B1 th => Mch Regu ang hot ng .

Nu mch Regu khng hot ng bn cn kim tra dao nga ti chn G n Mosfet, thang 50V DC o vo chn Gnh sau :

o dao ng ti chn G Mosfet thng thngkhi lm vic chn ny c t5 n 10V

o ti chn ra ca IC dao ng nh sau :

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XUANVINH


51/96

o dao ng ti chn ra ca IC thng thngkhi lm vic chn ny cng c t5 n 10V

T kt quo hai v trn cho ta bit :

- Nu in p ra ca IC dao ng (chn2) = 0V => hng ICdao ng .- Nu in p ra t IC dao ng khc vi in p sau 2 nkhuch i m Q1 v Q2 => hng cc n khuch i m Q1v Q2 (n Q1 v Q2 khuch i v dng, in p trc v sauhai n ny l khng thay i )

=> Trng hp ny bn cn thay hai n m Q1 v Q2 .

Trng hp o vn c in p dao ng ti chn G => Bn hythay thn Mosfet Q3 .

Lu : Mt s trng hp IC hng nhng vn cho p ra => l p mt chiu, v vy bit chnh xc l tn hiu dao ng=> bn hy s dng ng h Digital Multimeter c thang otn so kt hp .

Dngng h Digital Multimetero tn sdao ng

Nu tn s = 0 Hz l p mt chiu ( khng phi dao ng )

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52/96

Nu tn s l t 25KHz n 40KHz l tn s dao ng .

Trong cc trng hp o thy p dao ng ra = 0V hoc ra pmt chiu th bn cn phi thay IC dao ng .

Bnh 4 :

Hin tng :Khi bt cng tc => Cao p chy c 1 -2 giy li ngt

o in p G2 ti chn n hnh kim tra shotng ca cao p, sau khi bt cng tc ta thy c p

G2 sau 1 - 2 giy li mt => cao p va chy li ngt

Nguyn nhn :=> Do in p B+ tng => cao p hot ng mnh => mch

bo v ( XRAY ) ngt dao ng dng bo vn hnh .=> Do bn thn mch bo vn hnh c s c .=> Do cao p chp nh => dng tiu th cao p tng cao =>mch bo v cng ngt dao ng dng .

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53/96

Mch bo vn hnh thng c Diode Zener, khi p B+tng => cao p hotng mnh => in p i qua

Diode Zener D2 vo chn 2 (chn XRAY) => ct dao ng

Mch bo vn hnh ( mch mu tm)trong my SAMSUNG 753DFX

Kim tra :y l bnh kh sa v :- in p tn ti trong thi gian ngn => kh khn cho vic o

c- D xc nh mch bo v trn my l rt kh khn nu khngc s nguyn l .

Cc bc kim tra :- Trc ht bn hy kim tra k cao p v m bo chc chnl cao p khng hng trc khi kim tra tip .- o v theo di nhanh in p B+ xem in p c tng cao btthng khng ( thng thng nu phn gii 600 x 800 thin p B+ khng qu 100V DC )

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54/96

o nhanh p B+ nu phn gii 600 x 800th p B+ phi khng qu 100V

- Nu p B+ qu cao > 120V => bn cn kim tra mch hi

tip t cao p v mch dao ng Regu , VD mch SAMSUNG753DFX th bn cn kim tra cc linh kin R511, D501, C505,R506, R505, R504 .- Nu p B+ bnh thng => bn cn tm chn XRAY ( IC daong ) kim tra cc linh kin lin quan .- Tm Diode Zener xung quanh IC dao ng kim tra, hoctm tho th ra (nu c) sau th li .- Nu tho Diode zener ( bo v ) ra m my chy bnh thngth bn cn thay th Diode zener mi .

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55/96

Chng V - Khi qut mnh

1. Nguyn l v nhim v ca khi qut mnh .

Nhim v ca khi qut mnhKhi qut mnh c nhim v to ra in p xung cung cp chocun li tia qut mnh li dng tia in t qut theo chiu dcmn hnh .

ng vi mi xung mnh mn hnhqutc1 lt ttrn xung di

- Khi qut mnh bao gm tng dao ng ( V.OSC ) v tngkhuch i cng sut ( V.OUT ) , tng V.OSC to xung daong c tn s t 50Hz n 120Hz cung cp cho tng cngsut, tng cng sut V.OUT khuch i xung ln bin lnri a ra li tia iu khin dng tia in t qut theo chiudc.

Biu hin khi hng :Khi hng tng dao ng hoc hng tng cng sut, lm mtxung mnh cung cp cho li tia => mn hnh ch cn mt vchsng ngang

Khi mt xung mnh ra li tia, mn hnhcn mt vch sng ngang

Chiu cao ca hnh nh :Chiu cao ca hnh nh ph thuc vo bin xung mnh, bin

ny c thay i khi ta chnh nt V.Size , bin

xung mnh cng cao th hnh nh cng dn theo chiu dc ,

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56/96

bin xung mnh gim th hnh nh co li .

Bin xung thay i th chiu cao hnh thay i

Tuyn tnh ca hnh nh :Tuyn tnh l dn ng u trn ton b chiu dc, myhng tuyn tnh dn n hnh nh b mo dc, nguyn nhn camo tuyn tnh l do xung mnh b bin dng .

Dng xung mnh thay i th tuyn tnh thay i

Cun li tia qut mnh :Cun li tia qut mnh c qun bn ngoi v qun trn liferit , cun li mnh t khi b hng v in p lm vic thp,nhng cun li dng pha trong li rt hay b chp do in plm vic cao .

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57/96

u rc li tia cm trn my, dy vng v dy xanh l cy chocun li mnh, dy v dy xanh lcho cun li dng .

V tr khi qut mnh trn my :- Mch dao ng ca khi qut mnh c tch hp chung vimch dao ng ca khi qut dng trong mt IC, v vy daong dng u th dao ng mnh .

- Mch cng sut mnh l mt IC c to nhit , IC cng sutmnh thng c t 7 n 12 chn .

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58/96

Vmy Monitor Samsung Synmaster

IC to dao ng mnh (ng thi l IC dao ng dng )

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59/96

IC khuch i cng sut 7 chn, gn trn to nhit .

2 - Cc bnh thng gp ca khi qut mnh

Bn 1 - Mn hnh cn mt vch sng ngang .

Bnh 2 - Mn hnh co di, mo tuyn tnh .

Bnh 3 - Mn hnh co trn u, c tia qut ngc .

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60/96

Bnh 4 - Mn hnh co mt na, pha trn nh bnh thng .

Bnh 5 - Mn hnh co doc

Bnh 6 - Hnh b tri .

Bnh 7 - Hnh b lch tm dc

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61/96

3 - S nguyn l tng qut .

Khi qut mnh Monitor c ba dng mch cbn, sau y l s nguyn l tng qut ca ba mch cbn .

1 - Khi qut mnh c IC cng sut sdng ngun n 24V- Xung V.syn t my tnh i vo IC vi x l CPU to ra inp iu khin (Friquency control) , iu khin tn s qut mnhthay i cho ph hp vi phn gii mn hnh, tn s qutmnh ca Monitor thay i t 50Hz n 120Hz tu theo phn gii do phn mm quyt nh .=> Nu mt tn hiu V.SYN th mn hnh b tri

Mn hnh b tri do mt tn hiu ng b V.SYN

- V.OSC l mch to dao ng mnh, mch ny nm trong ICto dao ng chung cho c khi qut dng v mch tng pRegu .- V.OUT l IC khuch i cng sut, IC s dng ngun n24V

- IC c mt

ng dao

ng vo v mt

ng ra li tia- Ngun Vcc 24V ly t khi ngun

Nu mt 24V mn hnh chcn mt vch sng ngang

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62/96

- Sau li tia c t thot li xung Mass- in p ra li tia IC ny o c 12V DC so vi mass,

khi hng IC in p ny thng b lch khi gi tr trn .

S tng qut khi qut mnh sdng IC cng sut ngun n 24V

Hnh dng IC sdng ngun n 24V

2 - Khi qut mnh c IC cng sut ngun Kp +12V v -12V- Xung V.SYN v in p iu khin t CPU tng t mchtrn- Mch to dao ng to ra hai ng xung cung cp n ICcng sut, in p dao ng o c khong 2V DC .- IC cng sut c cung cp hai ngun in p i xng l+12V v -12V, c hai in p ny u c cung cp t khingun .- C hai ng ra li tia t IC cng sut, in p ra chn li tiaca IC ny bng 0V DC ( c hai chn u c 0V mt chiu - sovi mass )- Nu mt ngun +12V mn hnh ch cn mt vch sng ngang

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63/96

- Nu mt ngun -12V mn hnh b co mt na hnh pha di

Khi qut mnh sdng IC cngsut ngun kp 12V v -12V

Hnh dng IC sdng ngun kp +12V v -12V

3 - Khi qut mnh c IC cng sut ngun Kp 12V v 46V- Xung V.SYN v in p iu khin t CPU tng t mchtrn- Mch to dao ng to ra hai ng xung cung cp n ICcng sut- IC cng sut c cung cp hai ngun in 12V v 46V ccin p ny u c ly t khi ngun .- C hai ng dao ng i vo IC cng sut v hai ng inp ra li tiain p DC ra li tia so vi mass o c khong 6V = 1/2

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64/96

Vcc 12V .- Nu mt ngun +12V mn hnh cn mt vch sng ngang

- Nu mt ngun 46V mn hnh b co trn u v c mt s tiaqut ngc

Khi qut mnh sdng IC cngsut ngun kp 12V v 46V

Hnh dng IC sdng ngun kp +12V v +46V

4 - Phn tch s khi qut mnh Monitor Samsung

Synmaster 793DFX

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65/96

4.1 - S khi tng qut

S khi tng qut khi qut mnhMonitor Samsung 793DFX

Tn hiu xung ng b mnh V.SYN t my tnh a sangMonitorc a vo chn (30) CPU x l sau a rachn (29) => i qua trR331 sang chn (2) IC dao ng, tnhiu ny c nhim viu khin thay i tn s dao ng mnhkhi phn gii mn hnh thay i ( phn gii mn hnh phthuc vo s thit lp trong Windows ), trong trng hp mttn hiu V.SYN a sang chn s (2) IC dao ng < thngthng do t cp tn hiu > => tn s dao ng ra b sai =>mn nh b tri hnh theo chiu dc

Hin tng tri hnh

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66/96

IC OSC dao ng Dng - Mnh - v Regu, phn dao ngmnh gm cc chn 2, 19, 20, 22, 23 trong - Chn 2 nhn xung ng biu khin tn s- Chn 19 ni vi t lc ngun cho mch dao ng- Chn 20 ni vi t ca mch AGC tng iu chnh n nhtn s dao ng- Chn 22 ni vi t to thi hng ca mch dao ng, tin chn 22 (C331) c nh hng n tn s dao ng , nu t nytr s thay i => hnh nh cng b tri nh hin tng trn .- Chn 23 l chn dao ng ra, cung cp dao ng cho tngcng sut, dao ng ra c tn s t 60 n 85Hz v c in pDC khong 2 n 3V, ta s dng ng h c thang o tn s cth do c dao ng ra chn ny

V.OUT l IC khuch i cng sut bao gm cc chn :- Chn 1 nhn tn hiu dao ng ti- Chn 2 nhn Vcc 14V- Chn 3 ni vi t b in p- Chn 4 nhn Vcc -14V- Chn 5 l chn xung mnh i ra li tia, khi IC bnh thngchn ny c 0V mt chiu .

- Chn 6 nhn Vcc 14V- Chn 7 nhn p chun V-REF

Cc hhng v hin tng=> Nu mt ngun Vcc 14V cp vo chn 2 => mn hnh chcn mt vch sng ngang .=> Nu mt dao ng cp vo chn 1 => mn hnh cng chcn mt vch sng ngang .

Mn hnh cn mt vch sng ngang

=> Nu mt Vcc -14V cp vo chn s 4 => mn hnh b co

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67/96

mt 1/2 hnh pha di .

Mn hnh b co 1/2 hnh pha di

S mch cng sut mnh my Samsung 793DFX

=> Mch hi tip t sau li tia qua t C304 v R307 v chn s1 c nhim v sa mo tuyn tnh gip cho hnh nh c dnu theo chiu dc, trng hp hng t C304 hoc R307 =>mn nh s b mo tuyn tnh theo chiu dc mn hnh .

Hnh b mo tuyn tnh dc do hng cc linhkin ca mch hi tip

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68/96

IC cng sut mnh

4.2 Phn tch s chi tit khi qut mnh Samsung 793DFX

a) S mch dao ng Mnh ( & Dng + Regu )

Bn kch chut vo sxem r hn

S khi dao ng mnh (gm c dao ng dng v Regu)

b) S mch khuch i cng sut mnh

Bn kch chut vo sxem r hn

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70/96

ng dao ng i vo v hai ng xung mnh i ra li tia

Khi mt tn hiu V.SYN i vo CPU hay mt V.SYN i ti ICdao ng u dn n hin tng hnh nh b tri do tn s daong mnh b sai .

Hin tng tri hnh do mt xung V.SYN

Khi hng cc tchn 22, 24 tu mc hng m c th dnn mt dao ng hoch dao ng b sai,- Nu cc t b d => s mt dao ng ra => mn nh ch cnvch sng ngang ( tuy nhin trng hp ny t sy ra )- Nu cc t gim in dung => dao ng s ra sai lm cho hnhnh b tri

Vi tng cng sut nu :+ Mt ngun Vcc 15V => s dn n hin tng mn hnh ch

cn mt vch sng ngang .

Mn hnh chcn mt vch sng ngang- Trng hp IC cng sut b hng => mn hnh cng c hintng nh trn, khi hng IC cng sut thng thng in p rachn 6 s b lch ( khi bnh thng chn 6 c 6V n 7V DC )- Mt mt trong hai tn hiu dao ng ( v d long chn IC ) =>mn hnh s b lch theo chiu dc

+ Nu mt ngun Vcc 35V cp vo chn 7 => mn hnh s bco trn u v c mt s tia qut ngc .

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71/96

Bnh co trn du v c tia qut ngc

Cc lnh iu khin khi qut mnh nh lnh chnh tm dcV.CENT, lnh chnh chiu cao V.SIZE, u c thc hinthng qua hai ng SDA ( Signal Data ) v SCL ( SignalClock ) t CPU a sang IC dao ng, hai ng SDA v SCLc mch DAC chuyn i thnh cc lnh iu khin nh cclnh trn .

5.2 Phn tch s chi tit ca khi qut mnh MonitorLG710PH

a) S mch dao ng mnh (bao gm c dao ng dng,regu)

Bn kch chut vo sxem chi tit

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b) S mch cng sut mnh Monitor LG710PH - chi tit


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73/96

Chng VI - Khi VIDEO

1-Nguyn l tng hp tn hiu hnh nh trn my tnh.

Tn hiu hnh nh trn my tnh c lu dng tn hiu strn a cng hoc a CD Rom, khi ta mhnh nh ra, dliu ca File nh c np ln b nhRAM v c nh xsang b nhca Card Video sau chng c i thnh tn

hiu Analog Tn hiu Video Analog m Card Video cho ra gm 3 ng

- Tn hiu Video - R ( mang thng tin v mu ca nh )- Tn hiu Video - G ( mang thng tin v mu xanh l ca nh )- Tn hiu Video - B ( mang thng tin v mu xanh lca nh )

Ngun gc ca tn hiu R, G , B- Theo nguyn l phn tch v tng hp mu sc trong t nhinth mi mu sc bt k ta c th phn tch thnh ba mu cbnl (R), xanh l (G), xanh l(B) v ngc li t ba mu cbn trn ta cng c th tng hp thnh mt mu bt k, chnh vvy mt bc nh c hng triu mu nhng thc cht my tnhch lu li ba mu cbn ca mi im nh m thi .Ngun gc ca tn hiu R, G, B l do bc nh mu c phntch thnh ba bc nh ngay t khi chng mi c thu vo, sau cc bc nh ny c i thnh tn hiu Video nhnguynl qut hoc nhcc Sensor ( cm bin ) .

a vo my tnh lu tr hay x l, cc tn hiu R, G, Bphi c i thnh tn hiu s dng 0, 1

Khi cho hin th bc nh ra mn hnh, cc tn hiu s ca bcnh li c i thnh tn hiu Analog thng qua Card Videov cho ra ba tn hiu R, G, B sau cc tn hiu ny ckhuch i qua tng khuch i Video ri a ra n hnh

tng hp li hnh nh .

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74/96

Xl tn hiu trong my tnh khi pht hnh

Khuch i tn hiu Video trn Monitor

Nguyn l tng hp nh mu trn n hnh- Khi c ba tn hiu mu a n ba Katt , mn hnh s chora bc nh mu trung thc .

- Nu mt mt tn hiu mu a ti Katt R, mn hnh slch sang mu xanh lam do ch cn hai tn hiu xanh l v xanhltrn li

- Nu mt tn hiu mu xanh l a ti Katt G, mn hnh slch sang mu tm .

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- Nu mt tn hiu mu xanh la ti Katt B, mn hnh slch sang mu vng .

- Nu mt hai tn hiu th trn mn hnh s c mu ca tn hiucn li

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76/96

- Nu mt c ba tn hiu th mn hnh mt nh, ch cn mnsng m

Nguyn l trn nh trong t nhin c s dng trong cc thitb hin th mu c minh ho nh sau :

2. Nhim v, s v v tr - khi khuch i Video

Nhim v ca khi Video :- Khi Video c nhim v khuch i ba tn hiu mu l : R(), G (xanh l ) v B (xanh l) ln bin ln trc khia vo iu khin cc Katot n hnh pht x .- Ngoi ra khi Video cn trn tn hiu hin th, iu chnh tng phn, cn bng trng cho mn hnh .

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77/96

S khi khuch i Video tng qutKhi khuch i Video c hai tng chnh v hai mch ph- Tng tin khuch i Video - Pred Video Amply- Tng khuch i cng sut - Video OUT- Mch to hin th - Display- Mch cn bng trng - Bias

S tng qut khi K Video

Tng tin khuch i Video c nhim v khuch i ba tnhiu t Card Video a sang ln bin ln cung cp chotng khuch i cng sut, ngoi ra tng ny cn thc hin iuchnh tng phn, cn bng ba tn hiu R, G , B

Tng khuch i cng sut Video gm ba tng khuch i songsong, khuch i cho ba mu R, G, B, tng ny c th s dngcc cp Transistor hoc s dng IC cng sut .

Mch BIAS : l mch phn cc p mt chiu cho ba Katt,mch c nhim v cn bng trng cho mn hnh, cc my ic mch ny thng c ba bin trcn chnh l R-Bias, G-Biasv B-Bias . Trong cc my i mi, cc bin trny c thayth bng cc lnh t vi x l .

Mch Display gii m tn hiu hin th, tn hiu hin th t vi xl a ti thng qua hai ng Data v Clockc IC Display

gii m ly ra cc tn hiu R,G,B sau chn vo tn hiuVideo, IC Display c thc tch hp trong IC tin khuchi Video .

V tr khi khuch i Video

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78/96

Khi khuch i Video nm trn vui n hnh .

Cc IC trn khi khuch i Video

Trn vui n gm c cc IC- IC tin khuch i Video : l IC nhiu chn. IC tin khuchi s dng ngun Vcc 12V, ba tn hiu t CPU ti c athng vo IC ny, ba tn hiu ra c a sang IC khuch icng sut- IC khuch i cng sut : l IC gn trn to nhit . IC cngsut c Vcc l 90V, tn hiu vo i t IC tin khuch i ti, tnhiu ra cung cp cho ba Katt n hnh .- IC gii m hin th Display : l IC nh , Vcc cho IC Display l5V, tn hiu vo l Data v Clock ly t IC Vi x l, tn hiu ral R, G, B c a sang IC tin khuch i trn vi tn hiu

Video

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79/96

3 - Cc hin tng khi hng khi khuch i Video .

Hnh nh bnh thng

1. Hin tng my b sai mu .

Hin tng mn nh ng mu vng

Hin tng mn nh ng mu tm

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80/96

Hin tng mn nh ng mu xanh

2. Mn nh mt hnh, cn mn sng m.

Hin tng mt hnh, cn mn sng m

3. Mn nh trng xo c tia qut ngc

4. Hnh nh mnht

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81/96

4 - Card Video trn my tnh

Card Video trn my tnh

Nhim v ca Card Video :- Card Video c nhim vi tn hiu hnh nh t dng Digitalsang tn hiu Analog cho ra cc tn hiu R, G , B a sang mnhnh .- iu khin tn s qut ngang v qut dc trn mn hnh thngqua cc tn hiu ng b H.SYN v V.SYN .- B nhtrn Card Video c nhim v lu cc thng tin v ccim nh trn mn hnh, dung lng b nhca Card video cnh hng trc tip n phn gii v s mu sc c th hinth .

+ V d chy c mn hnh c phn gii 1024 x 768 v

c mu sc l 32 bit th cn dung dng b nhti thiu trnCard Video nh sau :- Mn hnh 1024 x 768 = 786432 Pixel ( im nh )- Mi im nh cn 32 bt lu tr thng tin v mu sc vcn ti khong 20 bt lu thng tin v to ngang v to dc, nh vy tng s mi im nh cn n khong 52 bittng ng vi 6,5 Byte.- Nh vy tng b nhcn thit lu try thng tin chomt mn hnh trn l786432 Pixel x 6,5 Byte = 5111808 Byte 5 MB

Nh vy c th hin th mn nh mu 32 bit vi phn gii1024 x 768 th ti thiu cn khong 5MB trong b nhCard

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82/96

Video- Nu hin th hnh nh ng nh Video, Game th cn thitc b nhcao gp nhiu ln khi hin th hnh nh tnh, nu bnhCard khng dung lng s lm cho hnh nh Video bgit cc khi hin th .

u cp ni vi my tnh c 3 ng tn hiu Video l R, G, Bv hai xung ing b H.SYN v V.SYN

5 - Nguyn l hot ng ca khi khuch i Video .

5.1 Khi khuch i Video c tng cng sut sdng Transistor

Khi khuch i Video c tng cng sut sdng Transistor

PRED AMPLY VIDEO l IC tin khuch i lm nhim vkhuch i ba tn hiu R, G, B, iu chnh tng phn,ghim mc chi, trn tn hiu hin th , v iu chnh cn bng

cho ba tn hiu mu .

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83/96

IC c cp ngun 12V, trong trng hp mt ngun Vcc 12Vhoc cht IC mn nh s mt hnh cn mn sng hoc nh bsai mu .

Mt hnh cn mn sng

Xung CLAMP t cao p hoc t vi x l a ti, xung ny ctn s bng tn s qut dng v c nhim v ghim mc thmcho tn hiu Video, nu mt xung CLAMP th mn nh b mthnh nh hin tng trn, xung CLAMP o ti chn IC ckhong 1V AC, ta c th kim tra chn CLAMP bng ng hc thang o tn s, tn s xung CLAMP bng tn s qut dng .

R IN, G IN, B IN l ba tn hiu Video t Card Video ca mytnh a sang, in p tn hiu ti cc chn ny rt yu khong0,1V AC chng c a vo IC khuch i .- Trong cc trng hp t cp tn hiu, mt tn hiu vo chnR, G hoc B => mn nh s b sai mu .

Mn nh ng mu tm do t cp

tn hiu G ( xanh l )

- Cc chn tn hiu ra ca IC c in p khong 2 n 2,5V DC,khi c ba tn hiu vo v IC tt th p mt chiu ra ti bachn ny phi bng nhau, trng hp mt tn hiu vo hochng mt v IC th in p ra s b lch .

Chn CONTRAS nhn lnh Contras t vi x l a ti iuchnh tng phn cho mn hnh, in p lnh Contras thayi t 2 n 5 V DC, nu mt lnh ny => nh trn mn hnh smhoc c th mt hnh cn mn sng mn .

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nh b mdo mtin p lnh Contras

DISPLAY l IC gii m tn hiu hin th, cc tn hiu hin tht vi x l a ti thng qua hai ng Data v Clock, chngc gii m ly ra cc tn hiu mu R, G, B sau emtrn vo tn hiu Video ca my .

DATA ( ng d liu ), CLOCK ( xung ng h ) hai ngny t Vi x l a ti mang thng tin v tn hiu hin th,ngoi ra trong cc my hin nay, cc lnh c iu khin t vix l nh Contras, R Bias, G Bias, B Bias cng c thc hinqua hai ng tn hiu trn .

V BLK v H BLK l xung mnh v xung dng cung cp chomch gii m hin th xc lp to hin th trn mn hnh .

Hai n Q1 v Q2 l tng cng sut khuch i cho tn hiu B,chng c mc ni tip tng h s khuch i, Q1 l nnh khng cn to nhit, Q2 l n cng sut gn trn tm tonhit .- Tn hiu c a vo chn B n Q1 khuch i qua hai nsau ly ra chn C n cng sut Q2 cho ghp qua t sang

Katt n hnh .- Tng cng sut c ba mch khuch i nh trn khuch icho ba mu R, G, B . Khi hng mt tng cng sut => mn nhcng b sai mu .

Hng tng cng sut R, mn nh b mt mu

* Nhim v cc linh kin xung quanh hai n cng sut :- R1 in trni tng t tin khuch i sang khuch i cngsut- R2 in trnh thin cho n cng sut Q2- R3 in trghnh cho n cng sut Q2

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XUANVINH


85/96

- R4 cung cp in p DC cho Ka tt* in p Vcc cho tng cng sut l 90V* in p nh thin cho tng cng sut l 12V .

n Q3 v bin trB Bias c nhim v phn cc p mt chiucho Katt B, c ba n v ba bin trnh vy phn cc p mtchiu cho ba Katt, trong trng hp mn nh b sai mu do pht x ca ba tia n hnh thay i, ta c th chnh li cc bintrBias cn bng trng cho mn hnh .- Nu mt trong cc n Bias b hng => in p trn ba Katts b lch, pht x ca ba tia s b lch => mn nh s b saimu tng t nh cc hin tng sai mu trn .

5.2 Khi khuch i Video c tng cng sut sdng IC

Khi khuch i Video c tng cng sut sdng IC

Tng cng sut s dng IC thay th cho ba cp Transistor- IC s dng hai ngun nui l Vcc1 = 90V v Vcc2 = 12V- Ba tn hiu vo R, G, B nhn tn hiu t IC tin khuch ia sang, cc tn hiu ra c ghp qua t sang ba Katt .

Mch Bias v mch Display c tch hp trong IC tin khuchi, cc iu khin v tn hiu hin th t vi x l c a qua

hai ng Data v Clock, sau c mch gii m trong ICtin khuch i cho ra cc tn hiu hin th v cc lnh iuchnh Bias, Contras v v... , lnh iu chnh cn bng trng Biasc cc Transistor bin iu thnh in p mt chiu a voKatot iu khin dng pht x tnh ca mn hnh .

V BLK v H BLK l xung mnh v xung dng cung cp chomch gii m hin th xc lp to hin th trn mn hnh .

IC tin khuch i c hai ng Vcc l 12V v 5V- Ngun Vcc 12V cung cp in p cho cc tng khuch i R,G, B- Ngun 5V cung cp in p cho mch gii m lnh v hinth .

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XUANVINH


86/96

- Xung Clamp ghim mc thm cho tn hiu, xung ny ccung cp t Cao p hoc t Vi x l, mt xung Clamp my smt hnh .

6- Phn tch khi khuch i VIDEO trn my thc t

6.1 Phn tch khi VIDEO ca Monitor SAMSUNG 793DFX


IC tin khuch i Video LM 1236

- Chn 1 - V BLK nhn xung mnh t IC cng xut mnh ticung cp cho mch gii m hin th .=> Nu mt xung V BLKi vo chn ny mn hnh s mt

hin th- Chn 2 - V_CAP Chn ni vi t lc ngun- Chn 3 - VREF_REXT qua trthot mass- Chn 4 - GND chn mass- Chn 5 - RIN chn nhn tn hiu R t CPU a ti=> Nu mt tn hiu i vo chn ny, mn hnh s mt mu,

hnh nh ng sang mu xanh .

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XUANVINH


87/96

- Chn 6 - GIN chn nhn tn hiu G t CPU a ti=> Nu mt tn hiu i vo chn ny, mn hnh s mt mu

xanh l,hnh nh ng sang mu tm .

- Chn 7 - BIN chn nhn tn hiu B t CPU a ti=> Nu mt tn hiu i vo chn ny, mn hnh s mt mntnh

l, hnh nh ng sang mu vng .

- Chn 8 - PLL_GND mass ca mch PLL- Chn 9 - PLL_FILTER chn dao ng ca mch PLL- Chn 10 - PLL_VCC Chn cp ngun cho mch PLL ( Vngkho pha ), mch PLL sa dng xung cho mch to hin th=> Mt in p chn ny mn hnh s mt hin th

- Chn 11 - SDA - D liu Data t vi x l cung cp cho mchhin th v gii m lnh=> Nu mt tn hiu Data => mn hnh s mt hin th

- Chn 12 - SCL - Xung ng h Clock t vi x l cung cp

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XUANVINH


88/96


89/96

- Chn 1 - R-OUT - tn hiu mu i ra cung cp cho Katot R

- Chn 2- G-OUT- tn hiu mu xanh l i ra cung cp choKatotG- Chn 3 - B-OUT - tn hiu mnhnh li ra cung cp choKatot B=> Khi IC bnh thng in p ra ti ba chn 1, 2, 3 tngng nhau v bng khong 2/3 VCC, trng hp in p ratrn 3 chn 1,2,3 khc nhau l c hai nguyn nhn

- Mt mt tn hiu u vo- Hng IC cng sut

- Chn 4 - VCC - chn cp ngun 80V.=> Nu mt ngun 80V cung cp cho mch khuch i

VIDEO, mn nh s sng trng v c tia qut ngc do mtin p DC trn ba Katot .

=> Nu cn 80V cung cp cho mch VIDEO nhng lng chnVCC hoc hng IC cng sut => mn nh s mt hnh cn mnsng m

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XUANVINH


90/96

- Chn 5 - Mass- Chn 6 - BIN - chn tn hiu xanh li vo IC=> Nu mt tn hiu BIN i vo chn 6 => mn nh s ngmu vng

- Chn 7 GIN chn tn hi xanh l i vo IC

=> Nu mt tn hiu GIN i vo chn 6 => mn nh s ngmu tm

- Chn 8 - VBB chn cp ngun 8V chi IC=> Nu mt in p 8V cp vo chn 8 => mn nh s mt

hnh do mt in p nh thin cho cc tng cng sut trong IC

- Chn 9 RIN chn tn hiu i vo IC=> Nu mt tn hiu RIN i vo chn 6 => mn nh s ngmu xanh

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XUANVINH


91/96

IC BIAS iu khin p DC cho ba Katt

- Cc chn 1, 2, 3 nhn lnh iu khin R-BIAS, G-BIAS v B-BIAS t mch gii m lnh nm trong IC tin khuch iVideo .- Cc chn 6, 7, 8 ni vi ba Katt xc lp p DC trn baKatt- Chn 5 - cp ngun 80V cho IC .=> Bnh thng in p DC trn ba Katt bng nhau v bngkhong 40V n 50V .=> Nu hng IC- BIAS in p trn 3 Katt c th b thay i

- Nu in p trn 3 Katot b lch , mn nh s b sai mu .- Nu in p trn 3 Katt tng bng ngun 80V => mn nhs mt nh sng do 3 Katt pht x yu .

- Nu mt in p trn 3 Katt => mn nh s sng trng vc tia qut ngc .

6.2 Phn tch khi VIDEO ca Monitor DEWO 523X

B

n kch chu

vo s

xem chi ti

t

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XUANVINH


92/96

IC Tin khuch i VIDEO

- Chn 1 - R GAIN lnh iu chng li cho mu - Chn 2 - RIN chn nhn tn hiu R t CPU a ti

=> Nu mt tn hiu R-IN ( thng do t cp tn hiu ) =>mn nh s ng mu xanh

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XUANVINH


93/96

- Chn 3 - G GAIN lnh iu chng li cho mu xanh l- Chn 4 - GIN chn nhn tn hiu G t CPU a ti

=> Nu mt tn hiu G-IN ( thng do t cp tn hiu ) =>mn nh s ng mu tm

- Chn 5 - R GAIN lnh iu chng li cho mu xanh l- Chn 6 - BIN chn nhn tn hiu B t CPU a ti

=> Nu mt tn hiu B-IN ( thng do t cp tn hiu ) =>

mn nh s ng mu vng

- Chn 7 - GND - Mass- Chn 8 - R OSD - tn hiu hin th mu - Chn 9 - Vcc in p ngun cung cp 8V- Chn 10 - G OSD - tn hiu hin th mu xanh l- Chn 11 - OSD CONT iu chnh tng phn cho tn hiu

hin th- Chn 12 - B OSD - tn hiu hin th mu xanh l- Chn 13 - CONT - iu chnh tng phn cho tn hiuVideo

=> Nu mt in p lnh CONTRAS hnh nh s mnht

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XUANVINH


94/96

hoc c th mt hnh .

- Chn 14 - F BLK chn nhn xung dng xc lp tohin th

=> Nu mt xung dng, mn hnh s mt hin th- Chn 15 - B OUT chn ra tn hiu B

- Chn 16 - B CAP - chn lc tn hiu B- Chn 17 - Vcc VIDEO - in p Vcc cho mch khuch iVideo=> Nu mt in p Vcc => mn nh s mt hnh, cn mnsng m

- Chn 18 - G CAP - chn lc tn hiu G- Chn 19 - GOUT - Tn hiu mu i ra a sang tng

cng sut- Chn 20 - V5 - Chn lc ngun- Chn 21 - R CAP - chn lc tn hiu R- Chn 22 - R OUT chn ra tn hiu R cung cp tn hiu chotng cng sut- Chn 23 - Clamp - xung Clamp t cap p a ti gimmc tn hiu Video

=> Nu mt xung CLAMP mn nh s mt hnh , cn mnsng m

- Chn 24 - H BLK - xung dng t cao p a n cung cpcho mch hin th .

=> Nu mt xung ny mn hnh s mt hin th .

Tng khuch i cng sut VIDEO.

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XUANVINH


95/96

Mt tng khuch i cng sut VIDEO - R

Tng khuch i cng sut c ba mch hot ng song songkhuch i cho ba mu R, G, B , ba tng ny c cu to v

nguyn l hot ng nh nhau .

* Vi tng khuch i R:- Q801 l n cng sut c to nhit- Q802 l n tin khuch i cng sut nh .=> Hai n mc ni tip tng h s khuch i .- R808 l trnh thin cho n cng sut Q1- R811 v R812 l in trghnh cho n cng sut Q1- Q803 v Q804 l hai n khuch i m lm cho cng tn hiu kho hn

=> Bt k h hng mt trong cc linh kin trn => s lm mtmt tn hiu mu a ti Katt R => lm cho mn nh b saimu ng mu xanh .

* Tng t nh vy vi tng cng sut G v B

- Ngun Vcc cho mch cng sut l 65V=> Nu mt in p 65V cp cho vui n => mn nh s

sng trng c tia qut ngc do mt in p DC trn 3 katt

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XUANVINH


96/96

- Ngun nh thin cho mch cng sut l 8V=> Tn hiu R tu ra IC tin khuch i c a vo chnB n Q802, sau khi khuch i tn hiu c ly ra chn Cn Q801 => cho khuch i m qua hai n Q803, Q804 sau ghp qua t C810 a sang KR ca n hnh .

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