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اليكم عطل واصلاح لجهاز فبستال 11AK08 & 11AK10 chassis
اليكم اعزائى الكرام نبذة اخرى عن العطل واصلاحة فى جهاز جديد يسمى فيستال (vestel)اتمنى من الله عز وجل ان ينال رضاكم كما مرفق بعد عرض العطل والاصلاح دائرة البور سبلاى الخاصة بالجهاز اتمنى ان تعجبكم وشكرا : 11AK08 / 11AK10- Intermittent height fluctuations Check for dry joints / broken print around height control VR702 11AK08 / 11AK10- Field cramping at bottom of screen Check capacitor C704 for leakage, if fault persists go on to check capacitors C701 & C702 (both 4.7nF) & C705 (3.3uF, 50v) 11AK08 / 11AK10- Field collapse Check the field chips 26v supply safety resistor R711 (4.7ohms), if open circuit suspect failure of the field output chip IC701 (TDA3653B), to prevent repeated failure of IC701 check for dry joints & print damage around the pins of IC701 itself 11AK08 / 11AK10- No or intermittent loss of colour Check capacitors C418 (100nF), C419 (4.7nF) & C420 (18pF) then the 4.43MHz crystal X401 11AK08 / 11AK10- First anode supply low Check the value of supply resistor R925 (470Kohms) & associated high voltage capacitor C907 11AK08 / 11AK10- Excessive red picture content Check feedback resistor R904 (680Kohms) for open circuit 11AK08 / 11AK10- Excessive green picture content Check feedback resistor R911 (680Kohms) for open circuit 11AK08 / 11AK10- Excessive blue picture content Check feedback resistor R918 (680Kohms) for open circuit 11AK08 / 11AK10- Loss of red picture content Check resistor R905 (1.2Kohms) & output transistor Q901 for open circuit 11AK08 / 11AK10- Loss of green picture content Check resistor R912 (1.2Kohms) & output transistor Q903 for open circuit 11AK08 / 11AK10- Loss of blue picture content Check resistor R919 (1.2Kohms) & output transistor Q905 for open circuit 11AK08 / 11AK10- Erratic operation / intermittent switches to standby / corrupt on screen display These problems are normally associated with failure of the ram chip IC502 11AK08 - Failure of the fet, TDA4605 etc This is almost invariably caused by R805 (330K) going o/c 11AK08- Power supply not starting up, no start up supply to pin 6 of the chopper control chip IC801 (TDA4605-2) Check start up resistor R802 (75Kohms,2w) for open circuit also check diode D806 (1N4148) for short circuit 11AK08- Dead, chopper transistor Q801 (BUZ77) short circuit Fusible resistor R809 (0.47ohms) will be open circuit, replace along with diode D808 (BA159) & chopper control chip IC801 (TDA4605-2) 11AK08- Power supply tripping Check capacitor C817 (1uF, 50v), zener diode D809 & diode D807 for failure also check the condition of the h.t preset VR801 (4.7Kohms) 11AK08- H.T incorrect Check the value of resistor R813 (5.6Kohms) & the condition of the h.t preset VR801 (4.7Kohms) 11AK08- Partial field collapse (IC701 ok) Check resistor R442 (330Kohms) & capacitors C426 (10nF) & C453 (33nF) associated with the ramp generator circuit of jungle chip IC401 (TDA8362A) 11AK08- Picture blanking (fault may be intermittent) Check flyback boost diode D701 (BYD33J) & capacitor C707 (100uF,63v) for leakage 11AK08- Grainy picture, a.g.c circuit not functioning correctly Check capacitor C428 (1uF,50v) associated with pin 48 of the jungle chip IC401 (TDA8362A) 11AK10- To access the service menus use the service code 734 11AK10- Dead, chopper transistor Q801 (BUZ77B) short circuit The associated Fusible resistor R809 will be open circuit, replace along with diode D808 (1N4937) & chopper control chip IC801 11AK10- Power supply not starting up, no start up supply to pin 6 of the chopper control chip IC801 Check start up resistors R802 & R826 (both 100Kohms, wired in series) for open circuit also check diode D806 for short circuit 11AK10- Power supply tripping Check capacitor C817 & diode D807 for failure also check the condition of the h.t preset VR801 (2.5Kohms) 11AK10- Partial field collapse (IC701 ok) Check resistor R442 (330Kohms) & capacitor C426 (33nF) associated with the ramp generator circuit of jungle chip IC401 (TDA8362A) 11AK10- Field foldover at top of screen Check the value of resistor R710 (680ohms) then Diode D701 for leakage 11AK10- Picture blanking (fault may be intermittent) Check flyback boost diode D701 (1N4003) & capacitor C707 (100uF,63v) for leakage 11AK10- Grainy picture, a.g.c circuit not functioning correctly Check capacitor C428 (2.2uF,25v) associated with pin 48 of the jungle chip IC401 (TDA8362A) دائرة البور سبلاى  |
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التعديل الأخير تم بواسطة : احمد حمادي بتاريخ 15-06-2010 الساعة 08:15 PM |
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