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Problema delicata NEI CE25


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Va salut,Am intalnit urmatoarea problema la un sasiu NEI CE25 ( CE28 ):tranzistorul final linii BU508AF se defecteaza invariabil dupa un anumit timp ( de la cateva ore la cateva luni ) ( la defectare apare scurtcircuit CE )S-au schimbat in prealabil transformatorul de linii, capacitoarele, s-au rebobinat toate bobinele din circuitele de corectie si comanda ale etajului BO, s-au refacut lipiturile.Formele de unda par corecte cand televizorul functioneaza.A intalnit cineva un defect similar sau are o sugestie?Va multumesc!baza

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LINE OUTPUT TRANSISTOR S/C (after 5 mins)Line drive voltage low, not turning TR128 (BU508A) off fast enough, usually TR105 (BC337)o/c, poss TR106 (JC501). Line drive voltage low, (no neg pulses) Track to R121/C312/R122broken, Why it affects drive voltage is unclear.Low dive or wrong frequency,Jungle module earth broken,usually on early Clarivox Pcb.R371 1R0 fusible O/C, Side effect of no E/W CorrectionLINE OUTPUT TRANSISTOR S/C IMMEDIATELYD116/D117 S/C, C132 (27n)O/C , C131 (9N1) O/c

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Am gasit unul din condensatoarele de pe bara de +154V ( 100uF/160V ) cu capacitate scazuta.L-am inlocuit.De asemenea, s-a inlocuit si BC337 ( am observat ca "originalul" avea o tensiune de deschidere pe jonctiunile B-E si B-C mai mica decat inlocuitorul ). Deocamdata unitatea este in probe. Vedem ce se mai intampla cu ea.Multumesc colegilor forumisti pentru sugestiile facute.

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