Hitachi CPT2177SF/DU color TV the boot after the "three noes", repair method of fault bright red indicator light |
| Time£º2014-07-22 09:36:37 Source£ºNetwork Author£ºUnknown Clicks£º1400 |
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Rjeservice manual download site
IC501 7 ~ 13} {finally test JiaoHang scanning circuit voltage is not normal, especially 7 foot line frequency pulse signal output terminal only 0.14 V (normal is 1.3 V), check IC501 24} {, 7 ~ 13} {foot damage of peripheral components without short circuit. Will Q791 welding in C794 is extreme when plus + 12 V power supply is connected, measuring IC501} {24 feet still amounted to less than 12 V voltage, 8.2 V, 7 feet voltage is not normal. Shutdown, remove plus + 12 v power supply, restore Q791, with a model 500 multimeter R x 100 IC501 Ω block test {} 24 feet of forward and reverse resistance, black pen for measuring 90 Ω Ω (normal is 1.8 k), red pen test for 66 Ω Ω (normal is 0.5 k), resistance is large. On the basis of the analysis, IC501 24} {foot line field scanning internal power short circuit, make its internal doesn't work, 7 feet without horizontal frequency pulse output, output stage will not work, line output transformer by each of the rectifier output dc voltage is 0. , in turn, consists of D761, C762 rectifier filter output, after the Q791 regulated by the D700, Q904 to IC501} {24 feet of a group of 12 v power is lost, and only + 9 v switching power supply output voltage, the Q904 conduction to IC501} {24 feet, double power supply into a single power supply, 24} {foot power supply can not meet the + 12 v. Also make line scanning circuit doesn't work. After replacing IC501, sound, light, everything is back to normal.Rjeservice manual download site
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