Common Faults & Maintenance rau Digital Multimeters
(1) Tsis muaj qhov pom ntawm lub ntsuas
Ua ntej, xyuas seb lub roj teeb hluav taws xob puas zoo li qub (ib lub roj teeb 9 V feem ntau siv; sim txawm tias cov roj teeb tshiab). Thib ob, xyuas seb lub fuse puas tau tshuab, lub tshuab hluav taws xob hluav taws xob puas ua haujlwm, thiab seb qhov tam sim no-txheej resistor yog qhib-circuited. Tom ntej no, tshuaj xyuas lub rooj tsav xwm hauv Circuit Court rau corrosion, luv Circuit Court los yog qhib circuits, tshwj xeeb tshaj yog nyob rau hauv lub main power supply circuit. Yog tias pom muaj qhov tsis xws luag, ntxuav lub rooj tsav xwm hauv Circuit Court kom sai, tom qab ntawd ziab thiab ua haujlwm soldering. Yog tias lub rooj tsav xwm hauv Circuit Court tsis zoo, ntsuas ob lub hwj chim input pins ntawm cov zaub IC kom paub tseeb tias cov khoom siv hluav taws xob zoo li qub. Yog hais tias qhov kev nyeem ntawv voltage yog ib txwm, cov zaub IC puas lawm thiab yuav tsum tau hloov. Yog tias cov khoom siv hluav taws xob tsis zoo, tshawb xyuas lwm cov ntsiab lus luv luv. Kho tej short circuits pom. Yog tias tsis muaj qhov luv luv los yog qhov ua txhaum txuas ntxiv tom qab kho, IC muaj qhov luv luv hauv Circuit Court thiab xav tau kev hloov pauv.
(2) Resistance range tsis ua kev ntsuas
Saib xyuas lub rooj tsav xwm hauv Circuit Court ua ntej kom pom tias muaj cov resistor nyob rau hauv qhov kev ntsuas qhov ntsuas hluav taws xob raug hlawv tawm. Hloov cov hluav taws kub nyhiab tam sim ntawd yog tias muaj. Yog tias tsis pom cov khoom tawg, ntsuas txhua qhov txuas txuas thiab hloov cov khoom puas. Yog hais tias tag nrho cov khoom siv peripheral zoo li qub, qhov sib xyaw ua ke raug puas tsuaj thiab yuav tsum tau hloov.
(3) Kev nyeem ntawv tsis raug thaum ntsuas qhov hluav taws xob siab nrog qhov ntsuas hluav taws xob, lossis kev nyeem nrawm thiab tsis ruaj khov tom qab lub sijhawm ntsuas luv luv
Hom kev ua txhaum no feem ntau tshwm sim los ntawm kev ntsuas tsis txaus ntawm ib lossis ob peb yam. Yog tias cov khoom no kub dhau li ntawm ob peb feeb tom qab nres ntsuas, cov teebmeem thermal tshwm sim los ntawm lub zog tsis txaus yog qhov ua rau. Xws li cov khoom (lossis kev sib xyaw ua ke) yuav tsum tau hloov.
(4) Tam sim no ntau yam tsis tuaj yeem ua kev ntsuas
Feem ntau cov faults no tshwm sim los ntawm kev ua haujlwm tsis raug. Xyuas seb tam sim no-limiting resistors thiab voltage-dividing resistors raug hlawv tawm; hloov lawv yog tias puas. Tom qab ntawd xyuas cov xov hlau txuas mus rau lub amplifier kom puas; rov txuas cov kab tawg. Yog tias qhov txhaum tseem tsis tau daws, hloov lub amplifier.
(5) Kev nyeem tsis ruaj khov nrog tus lej hla
Xyuas seb tag nrho lub rooj tsav xwm hauv Circuit Court puas ntub los yog raug kev txom nyem los ntawm cov dej ntws tawm. Ntxuav lub rooj tsavxwm thiab ua kom qhuav yog tias muaj. Txheeb xyuas cov khoom siv hluav taws xob rau kev sib cuag tsis zoo lossis cov pob qij txha txias (nrog rau cov kev xeem coj). Resolder pob qij txha yog tias pom muaj teeb meem. Tshawb xyuas cov resistors degraded los yog cov khoom uas tau kub heev tom qab ntsuas, uas yog tshwm sim los ntawm kev txo hwj chim. Hloov cov khoom no.
(6) Cov ntawv nyeem tsis raug
Qhov teeb meem no feem ntau yog tshwm sim los ntawm kev ua tsis tau tejyam resistors lossis capacitors hauv kev ntsuas Circuit Court; cov faulty resistors los yog capacitors yuav tsum tau hloov. Ntsuas qhov ntsuas qhov ntsuas hauv qhov hluav taws xob no (suav nrog cov nqi tiv thaiv hauv qab thermal teb). Hloov cov resistors yog tias lawv tsis kam drifts los yog hloov nrog kub. Xyuas cov resistors thiab capacitors nyob rau hauv qhov siv voltage Circuit Court ntawm A / D converter thiab hloov qhov puas.
