Nws yog lub sijhawm los mloog zoo rau qee cov ntsiab lus hauv kev tshawb pom ntawm PCB pawg thawj coj saib, yog li txhawm rau npaj tau zoo kom ntseeg tau cov khoom lag luam zoo. Thaum kuaj pom PCB lub rooj tsavxwm, peb yuav tsum ua tib zoo mloog txog 9 qhov kev nkag siab hauv qab no.

1. Nws raug txwv tsis pub siv cov cuab yeej ntsuas hauv av txhawm rau hu xov tooj cua, suab, vis dis aus thiab lwm yam khoom siv hauv qab phaj kom pom lub PCB pawg thawj coj yam tsis muaj kev hloov pauv.

Tsis txhob ntsuas TV, suab, thiab cov vis dis aus ncaj qha yam tsis muaj lub zog cais tawm hloov pauv nrog cov cuab yeej siv hauv av. Txawm hais tias feem ntau cov kaw suab muaj lub zog hloov pauv, thaum nthuav tawm tshwj xeeb tshwj xeeb lossis loj dua lub zog ntawm qhov xwm txheej ntawm lub zog hluav taws xob tsis paub ntau txog TV lossis cov cuab yeej tso suab, thawj zaug ua kom pom tseeb lub tshuab chassis raug them, txwv tsis pub yooj yim thiab hauv av nyob TV, suab thiab lwm yam cuab yeej siv hluav taws xob muab hluav taws xob, kis mus rau hauv kev sib koom ua ke, txuas ntxiv mus.

2. Ua tib zoo saib xyuas cov rwb thaiv tsev ntawm cov hlau txuas hluav taws xob thaum kuaj pom PCB pawg thawj coj

Nws tsis raug tso cai siv cov hlau txuas nrog lub zog nyob. Txhawm rau kom paub tseeb tias cov hlau tsis muaj sia nyob, nws yog qhov zoo tshaj los tsaws lub plhaub ntawm cov hlau txuas. MOS Circuit Court yuav tsum tau ceev faj ntau dua, thiab nws muaj kev nyab xeeb dua los siv cov hlau hluav taws xob qis nrog 6-8V.

3. Ua ntej kuaj PCB pawg thawj coj, peb yuav tsum nkag siab txoj cai ua haujlwm ntawm kev sib koom ua ke thiab kev cuam tshuam hauv Circuit Court

Ua ntej kuaj xyuas thiab kho cov kab hluav taws xob sib xyaw ua ke, peb yuav tsum xub paub txog kev ua haujlwm ntawm cov khoom siv sib txuas, sab hauv hluav taws xob, cov hluav taws xob tseem ceeb, lub luag haujlwm ntawm txhua tus pin thiab qhov hluav taws xob ib txwm muaj, kev hloov pauv ntawm tus pin thiab txoj cai ua haujlwm ntawm cov khoom siv hluav taws xob muaj ib puag ncig Cheebtsam. Yog tias muaj cov xwm txheej no, kev tshuaj xyuas thiab tshuaj xyuas yog yooj yim dua.

4, kuaj PCB pawg thawj coj tsis ua rau luv Circuit Court ntawm tus pin

Kev ntsuas qhov ntsuas hluav taws xob lossis oscilloscope sojntsuam ntsuas cov yoj, tus cwj mem lossis sojntsuam tsis ua rau luv Circuit Court ntawm cov pins ntawm kev sib txuas hauv Circuit Court vim qhov swb, nws yog qhov zoo tshaj kom txuas ncaj qha nrog cov pins ntawm cov khoom siv sab nrauv luam ntawv rau ntsuas. Ib qho xwm txheej luv luv tam sim tuaj yeem yooj yim ua rau INTEGRATED circuit, yog li yuav tsum tau saib xyuas ntxiv thaum kuaj cov tiaj tiaj CMOS kev sib txuas ua ke.

5, detection PCB board test instrument internal resistance should be large

Thaum ntsuas DC qhov hluav taws xob ntawm tus pin ntawm kev sib txuas hauv Circuit Court, siv lub multimeter uas nws qhov kev tiv thaiv sab hauv ntau dua 20K ω /V; txwv tsis pub, yuav muaj qhov ntsuas loj yuam kev rau qee tus pin voltages.

6. Ua tib zoo saib xyuas cov cua sov ua kom sov ntawm cov hluav taws xob sib xyaw ua ke thaum kuaj pom PCB pawg thawj coj

Power integrated circuits should have good heat dissipation and should not be allowed to work in a high power state without heat sink.

7, PCB pawg thawj coj saib xyuas yuav tsum tsim nyog

Yog tias nws yog qhov tsim nyog yuav tsum tau ntxiv cov khoom siv sab hauv los hloov cov khoom puas hauv sab hauv kev sib txuas ua ke, cov khoom me me yuav tsum raug xaiv, thiab cov thaiv yuav tsum tsim nyog kom tsis txhob muaj kab mob sib kis uas tsis tsim nyog, tshwj xeeb tshaj yog txhawm rau cuam tshuam nrog qhov xaus hauv nruab nrab ntawm lub suab sib txuas ua ke preamplifier Circuit.

8. Txheeb xyuas qhov vuam zoo ntawm PCB pawg thawj coj saib

Thaum vuam yog welded tiag tiag, kev sib txuam ntawm cov laug thiab cov pores yog qhov yooj yim ua rau vuam virtual. Lub sijhawm vuam feem ntau tsis ntau tshaj 3 vib nas this, thiab lub zog ntawm cov hlau txuas yog li 25W. Kev sib xyaw ua ke tau txuas rau txhawm rau ua tib zoo tshawb xyuas, nws yog qhov zoo tshaj los siv ohmmeter los ntsuas seb puas muaj qhov luv Circuit Court ntawm cov pins, lees paub tias tsis muaj qhov cuam tshuam los ntawm kev sib txhuam thiab tom qab ntawd hloov lub zog hluav taws xob.

9, kev txheeb xyuas PCB pawg thawj coj tsis yooj yim txiav txim siab kev puas tsuaj ntawm kev sib xyaw ua ke

Do not easily judge that the integrated circuit is damaged. Vim tias feem ntau ntawm cov kev sib txuas ua ke tau ncaj qha ua ke, ib zaug hauv Circuit tsis txawv txav, nws tuaj yeem ua rau muaj kev hloov pauv ntau zaus, thiab cov kev hloov pauv no tsis tas yuav tshwm sim los ntawm kev puas tsuaj ntawm kev sib koom ua ke, thiab qee zaum, ntsuas tus pin pin yog zoo ib yam lossis ze rau tus nqi ib txwm muaj, nws yuav tsis tuaj yeem qhia pom tias kev sib xyaw ua ke tau zoo. Vim tias qee qhov ua yuam kev tsis ua rau muaj kev hloov pauv hauv DC voltage.

PCB board debugging method

Txog rau PCB lub rooj tsav xwm tshiab nyuam qhuav rov qab los, peb yuav tsum xub ua tib zoo saib seb puas muaj teeb meem ntawm lub rooj tsavxwm, xws li seb puas muaj qhov tawg tawg, txawm tias muaj luv Circuit Court, qhib Circuit Court thiab lwm yam tshwm sim. If necessary, check that the resistance between the power supply and the ground is large enough.

Rau lub rooj tsav xwm tsim qauv tshiab, kev debug feem ntau ntsib qee qhov nyuaj, tshwj xeeb tshaj yog thaum pawg thawj coj loj dua, cov khoom siv ntau dua, feem ntau tsis paub yuav pib li cas. Tab sis yog tias koj paub txoj hauv kev daws teeb meem tsim nyog, kev debugging yuav tau txais ob zaug qhov txiaj ntsig nrog ib nrab ntawm kev mob siab rau.

PCB txheej txheem kev debugging txheej txheem

1. For the new PCB board just brought back, we should first roughly observe whether there are problems on the board, such as whether there are obvious cracks, whether there are short circuits, open circuits and other phenomena. If necessary, check that the resistance between the power supply and the ground is large enough.

2, thiab tom qab ntawv txhim kho cov khoom siv. Cov qauv ywj pheej, yog tias koj tsis ua kom ntseeg tau tias lawv ua haujlwm tau zoo, nws yog qhov zoo tshaj tsis txhob teeb tsa lawv txhua tus, tab sis ib feem ntawm kev teeb tsa (rau cov kab hluav taws xob me me, tuaj yeem teeb tsa ib zaug), yog li nws yooj yim los txiav txim qhov ua txhaum. ntau, yog li thaum koj ntsib teeb meem, tsis paub yuav pib li cas.

Generally speaking, you can install the power supply part first, and then check whether the power supply output voltage is normal. Yog tias koj tsis paub meej heev thaum lub hwj chim qhib (txawm tias koj yog, koj raug qhia kom ntxiv fuse, tsuas yog qhov xwm txheej), koj tuaj yeem txiav txim siab siv qhov ntsuas hluav taws xob hloov pauv tau nrog kev txwv tam sim no.

Ua ntej tshaj tawm qhov kev tiv thaiv tam sim no, thiab tom qab ntawd tus nqi hluav taws xob ntawm tus tswj hwm lub zog xa khoom maj mam nce, thiab saib xyuas cov tswv yim tam sim no, cov tswv yim hluav taws xob thiab cov hluav taws xob tso tawm. If no overcurrent protection occurs and the output voltage is normal, the power supply is OK. Txwv tsis pub, disconnect lub hwj huam mov, nrhiav qhov ua txhaum, thiab rov ua cov kauj ruam saum toj no kom txog thaum lub zog siv tau ib txwm muaj.

3, tom qab ntawd maj mam txhim kho lwm cov qauv, txhua qhov kev teeb tsa tau teeb tsa, lub zog ntsuas, lub zog ua raws li cov kauj ruam saum toj no, txhawm rau zam kev dhau mus thiab hlawv cov khoom siv vim tsim tsis raug lossis teeb meem yuam kev.

Nrhiav qhov kev daws teeb meem ntawm PCB tsis raug

1. Ntsuas qhov ntsuas hluav taws xob kom pom lub PCB tsis raug

Thawj qhov kom paub tseeb tias seb qhov hluav taws xob ntawm lub hwj huam hluav taws xob tus pin zoo li qub, thiab tom qab ntawd txheeb xyuas seb txhua yam kev siv hluav taws xob zoo li qub, thiab seb qhov ua haujlwm voltage ntawm txhua kis yog qhov zoo li cas. Piv txwv li ib txwm muaj silicon triode, yuav muaj BE qhov sib txuas hluav taws xob nyob ib puag ncig 0.7V thiab CE txuas hluav taws xob ib puag ncig ntawm 0.3V lossis tsawg dua. Yog tias triode muaj BE qhov sib txuas hluav taws xob ntau dua 0.7V (tshwj tsis yog tshwj xeeb triodes xws li Darlington tubes), BE kev sib tshuam yuav raug qhib.

2, teeb tsa txoj kev txhaj tshuaj kom pom qhov ua txhaum PCB pawg thawj coj saib

Add the signal source to the input end, and then measure the waveform of each point in turn to see whether it is normal to find the fault point. Qee zaum peb tseem yuav siv txoj hauv kev yooj yim dua, xws li tuav lub tweezer txhawm rau txhawm rau lub davhlau ya nyob twg ntawm txhua qib kom pom tias muaj qhov tshuaj tiv thaiv ntawm lub davhlau ya nyob twg, uas feem ntau siv hauv lub suab thiab vis dis aus lub suab txuas (tab sis nws yuav tsum tau sau tseg) tias txoj hauv kev no tsis tuaj yeem siv hauv kev sib txuas nrog cov phaj kub kub lossis cov hluav taws xob hluav taws xob siab, txwv tsis pub nws yuav ua rau hluav taws xob poob). Yog tias tsis muaj tshuaj tiv thaiv ua ntej kov, thiab muaj qhov tshwm sim tom qab kov, nws qhia tau tias qhov teeb meem nyob rau qib dhau los, yuav tsum tsom mus rau kev tshuaj xyuas.

3. Lwm txoj hauv kev txhawm rau nrhiav cov PCB tsis raug

There are many other ways to find trouble spots, such as seeing, hearing, smelling, and touching.

“Saib” yog saib seb puas muaj cov cuab yeej ua kom puas rau cov khoom, xws li tawg, ua kom dub, hloov pauv, thiab lwm yam;

“Mloog” yog mloog seb lub suab ntawm kev ua haujlwm zoo li qub, xws li qee yam yuav tsum tsis txhob nyob hauv lub nplhaib, lub nplhaib tsis nrov lossis lub suab tsis zoo ib yam;

“Hnov” yog tshuaj xyuas seb puas muaj ntxhiab tsw, xws li tsw ntxhiab ntawm qhov hlawv, lub tshuab hluav taws xob zoo li qub, rau cov neeg ua haujlwm kho hluav taws xob uas paub dhau los, nkag siab zoo rau cov ntxhiab tsw;

“Touch” is to use the hand to test whether the temperature of the device is normal, such as too hot, or too cold.

Qee lub zog siv hluav taws xob, thaum ua haujlwm, cua sov, yog tias nws txias rau qhov kov, koj tuaj yeem txiav txim siab qhov tseeb tias nws tsis ua haujlwm. But if it’s hot where it shouldn’t be or too hot where it should be, that’s no good. General power triode, voltage regulator chip, etc., working in 70 degrees is completely no problem. 70 degrees txhais li cas? If you can hold your hand on it for more than three seconds, the temperature is probably below 70 degrees (be careful not to burn your hand).