Hitachi CTP-236 color Diantong boot without light, silent, listen carefully without any noise fault repair method machine |
| Time£º2014-07-28 10:08:27 Source£ºNetwork Author£ºUnknown Clicks£º1757 |
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NdTservice manual download site
NdTservice manual download site
Based on the above analysis combined with the cases of failure phenomenon, a preliminary judge fault in the power supply circuit. Therefore, we should focus on check this part of the circuit. NdTservice manual download site
NdTservice manual download site
Concerned in the open box back cover, visual inspection machine components, found the AV fuse P901 (TZA) fuse and black tube, explain the phenomenon has serious short circuit in machine. NdTservice manual download site
NdTservice manual download site
The multimeter electric barrier on the components to the switch power supply circuit of the road test, found the switch tube VT901 c and e interelectrode breakdown, VT903 pipe damage. Replace with same transistor under V1901 (note: when installing VT901 tube, should it according to the sample b and e feet set small magnetic ring, to suppress harmonic interference) of switch power supply and VT903 tube, in the case of confirmed switch circuit and trouble-free element power boot, found that only about 83 v + l08V voltage, and the speaker inside there was a low "om" sound, estimates that this is under the heavy load. NdTservice manual download site
NdTservice manual download site
Inspection on line output transformer and other components, it is found that focus line output transformer voltage output to ground resistance is only about 89 k Ω (normal value should be greater than 5 m Ω), determine the line output transformer internal breakdown phenomenon (Hitachi CTP - 236 type machine flyback transformer such high failure rate). In a same line output transformer, grating appear on the screen, but narrow line picture, image has no color, sound to ask questions. Then again + 108 v output measurement of voltage, found its value and rose to about 121 v, check + 54 v and line flyback transformer provide + 12 v low voltage and so on also are on the high side, so high pressure and ultrahigh pressure also increases, in this way, because of the effect of high pressure and ultrahigh pressure numerical partial higher factors, will inevitably make the line narrowing. This suggests that the power supply circuit is defective.
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