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miticamy

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About miticamy

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    Metrou Costin Georgian

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  1. Google este in concediu? https://www.google.ro/search?ei=ZLfpW4_gIqvSrgTI-o7oAQ&q=nf+smd+mark+transistor&oq=nf+smd+mark+transistor&gs_l=psy-ab.3...65042.71037.0.71787.8.8.0.0.0.0.179.963.1j7.8.0....0...1.1.64.psy-ab..0.4.548...0i8i7i30k1j35i304i39k1j0i30k1j0i8i30k1.0.Ywhyz3l3L_o
  2. miticamy

    Osciloscop pt colectionari

    Osciloscop categoria grea (30kg?) venit la FCE la infiintare. Azi l-am pus in priza dupa 20 ani si spre surprinderea mea au aparut spoturile. Are nuvistoare la intrare parca. PRET: o memorie de 1G sau un hard de 160 sau peste.
  3. Un sasiu 11ak30 fara bobine deflexie si fara antena. Cum isi pregateste STV semnalul video pt citire curent tub folosit la axare catozi: Oscul este sincronizat cu cadrele si vertical pe 2V/div.
  4. miticamy

    sursa 17IPS11

    Si in asta te-ai impiedicat? Nu ai PDF-ul integratului?
  5. miticamy

    Probleme Sursa DELL F280E-00

    Ati luat-o p'asta cu becul de la depanatorii tv dar ce te faci cand este si un PFC ca in cazul de fata.
  6. miticamy

    TV CRT Samsung model CK20S20BT

    Si TDA884x din acest tv: RGB output circuit and black-current stabilisation The colour-difference signals are matrixed with the luminance signal to obtain the RGB-signals. The TDA 884X devices have one (linear) RGB input. This RGB signal can be controlled on contrast and brightness (like TDA 8374/75). By means of the IE1 bit the insertion blanking can be switched on or off. Via the IN1 bit it can be read whether the insertion pin has a high level or not. The TDA 885X IC’s have an additional RGB input. This RGB signal can be controlled on contrast, saturation and brightness. The insertion blanking of this input can be switched-off by means of the IE2 bit. Via the IN2 bit it can be read whether the insertion pin has a high level or not. The output signal has an amplitude of about 2 volts black-to-white at nominal input signals and nominal settings of the controls. To increase the flexibility of the IC it is possible to insert OSD and/or teletext signals directly at the RGB outputs. This insertion mode is controlled via the insertion input (pin 26 in the S-DIP 56- and pin 38 in the QFP-64 envelope). This blanking action at the RGB outputs has some delay which must be compensated externally. To obtain an accurate biasing of the picture tube a “Continuous Cathode Calibration” circuit has been developed. This function is realised by means of a 2-point black level stabilisation circuit. By inserting 2 test levels for each gun and comparing the resulting cathode currents with 2 different reference currents the influence of the picture tube parameters like the spread in cut-off voltage can be eliminated. This 2-point stabilisation is based on the principle that the ratio between the cathode currents is coupled to the ratio between the drive voltages according to: The feedback loop makes the ratio between the cathode currents Ik1 and Ik2 equal to the ratio between the reference currents (which are internally fixed) by changing the (black) level and the amplitude of the RGB output signals via 2 converging loops. The system operates in such a way that the black level of the drive signal is controlled to the cut-off point of the gun so that a very good grey scale tracking is obtained. The accuracy of the adjustment of the black level is just dependent on the ratio of internal currents and these can be made very accurately in integrated circuits. An additional advantage of the 2-point measurement is that the control system makes the absolute value of Ik1 and Ik2 identical to the internal reference currents. Because this adjustment is obtained by means of an adaption of the gain of the RGB control stage this control stabilises the gain of the complete channel (RGB output stage and cathode characteristic). As a result variations in the gain figures during life will be compensated by this 2-point loop. An important property of the 2-point stabilisation is that the off-set as well as the gain of the RGB path is adjusted by the feedback loop. Hence the maximum drive voltage for the cathode is fixed by the relation between the test pulses, the reference current and the relative gain setting of the 3 channels. This has the consequence that the drive level of the CRT cannot be adjusted by adapting the gain of the RGB output stage. Because different picture tubes may require different drive levels the typical “cathode drive level” amplitude can be adjusted by means of an I2C-bus setting. Dependent on the chosen cathode drive level the typical gain of the RGB output stages can be fixed taking into account the drive capability of the RGB outputs (pins 19 to 21). More details about the design will be given in the application report. The measurement of the “high” and the “low” current of the 2- point stabilisation circuit is carried out in 2 consecutive fields. The leakage current is measured in each field. The maximum allowable leakage current is 100 mA When the TV receiver is switched-on the RGB output signals are blanked and the black current loop will try to set the right picture tube bias levels. Via the AST bit a choice can be made between automatic start-up or a start-up via the m-processor. In the automatic mode the RGB drive signals are switched-on as soon as the black current loop has been stabilised. In the other mode the BCF bit is set to 0 when the loop is stabilised. The RGB drive can than be switched-on by setting the AST bit to 0. In the latter mode some delay can be introduced between the setting of the BCF bit and the switching of the AST bit so that switch-on effects can be suppressed. It is also possible to start-up the devices with a fixed internal delay (as with the TDA 837X and the TDA884X/5X N1). This mode is activated with the BCO bit. The vertical blanking is adapted to the incoming CVBS signal (50 Hz or 60 Hz). When the flyback time of the vertical output stage is longer than the 60 Hz blanking time the blanking can be increased to the same value as that of the 50 Hz blanking. This can be set by means of the LBM bit. For an easy (manual) adjustment of the Vg2 control voltage the VSD bit is available. When this bit is activated the black current loop is switched-off, a fixed black level is inserted at the RGB outputs and the vertical scan is switched-off so that a horizontal line is displayed on the screen. This line can be used as indicator for the Vg2 adjustment. Because of the different requirements for the optimum cut-off voltage of the picture tube the RGB output level is adjustable when the VSD bit is activated. The control range is 2.5 ± 0.7 V and can be controlled via the brightness control DAC. It is possible to insert a so called “blue back” back-ground level when no video is available. This feature can be activated via the BB bit in the control2 subaddress.
  7. miticamy

    TV CRT Samsung model CK20S20BT

    Se pare ca nuai inteles ca acea definitie este un banc. Cum se poate modifica inalta tensiune cu frecventa cadrelor sau mai exact care este mecanismul prin care s-ar putea modifica inalta? Pinul 22 este pt axarea video pt a reduce curentul de fascicul citind tot cadrul, pinul 18 este pt citire curent fascicol pe cursa inversa cadre pe un fond negru. Si nu se citeste dezechilibrul intre culori ci emisia totala insumata pe cele 3 cai. Daca o culoare nu are emisie normala si suma va fi mai mica si nu se va comuta finalul video pe imagine. In functionare normala fiecare culoare va fi citita independent pt a se face axarea functie de emisia fiecarui catod, de aceea nu exista niciun semireglabil pe modulul video la acest tip de reglaj. Exista o logica complexa care deschide niste porti un timp limitat si in momente bine stabilite, aplicarea unei tensiuni in afara acelor momente poate bloca sistemul.
  8. miticamy

    TV CRT Samsung model CK20S20BT

    Bancurile se posteaza la Bodega.
  9. Asa se intampla daca"insertiile" de teorie sunt trecute cu vederea. Cand a mai fost un caz identic eu nu ma jucam cu simulatoare dar am facut montajul pe masa si am raspuns colegului ca este normal sa se intample asa. Voi insa v-ati repezit cu diverse scenarii ajungand chiar pana la magazinul cu aprovizionarea. ISTORIC: Posted Monday at 07:26 PM Am constatat, prin masurători, o tensiune pe puntea redresoare de aprox. 50 V cc în gol, Posted Monday at 08:38 PM (edited) Domnule Marian, pe eticheta transformatorului folosit de mine este trecută o tensiune nominala de 24 V, la măsurare indicând 26 V. Posted Monday at 09:54 PM Cel mai corect ar fi sa masurati transformatorul in gol - fara punte redresoare, ignorati eticheta. Este imposibil ca din 24Vca redresat si filtrat sa obtineti 50Vcc. Trebuie sa aveti undeva la 33-34Vcc Marian Posted Monday at 10:19 PM Mihai scuze dar eu nu-mi explic cum ar putea fi posibil sa obtii 50Vcc de la 26Vca de aia am dedus ca ai mers pe alimentare mai mare. vijelie Nici cresterea tensiunii din secundar la conectarea puntii, nu mi-o explic ( ca zici ca fara punte ai 26Vca, si cu puntea ai 27Vca ) sesebe Posted Monday at 11:55 PM Asa cum nu am explicație la creșterea aia de tensiune... Marian Posted yesterday at 01:04 AM Mihai nu-ti cere scuze ca n-ai motiv. Acei 50V sunt o anomalie, fie este o eroare de la multimetru, fie folosesti redresare cu dublare de tensiune, fie...nu stiu, chiar nu-mi dau seama, dar 26Vca n-au de unde sa dea mai mult de 35-36Vcc. Pana nu lamuresti treaba cu alimentarea, nimic nu poate fi sigur... modoran Posted yesterday at 05:30 AM Presupun ca toate componentele folosite sunt de la mivarom, nu ? Atunci orice este posibil.
  10. Nu are treaba cu calitatea componentelor.
  11. A mai avut cineva acum 3-5 ani aceeasi problema. Trebuie puse si alte rezistente pe cond. de 10mF de pe redresare, incepe tot cu 4,7k si scade poate pana la 1k. De fapt trebuie sa urmaresti la ce valoare nu mai creste tensiunea.
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