Panasonic model TV TC29GF80R, TC29GF80G, TC29GF90R, TC29GF90G, TC29GF85G, TC29G92G, TC33GF8IG, TC33GF85R series are used M18M, M19 core, the circuit using I2C bus control mode, color performance is good, easy expansion of functions. But in recent years, frequent failure, if the routine maintenance, easy to fall into a wrong path, sometimes for a lot of components, or repair bad, and even some element can not buy, was sentenced to "death with reprieve". I recently built this series of color TV sets, and some are "transfer machine", summed up a set of effective methods for maintenance, will be documented, valuable, inappropriate, please the majority of peer criticism.QeLservice manual download site
The common fault of this kind of models are: black boot, but the filament light, a sound; the boot image is normal, but only small distortion sound; just machine level a bright line, or bounce up and down, seems to be the field output integrated pin solder, a few minutes or ten minutes after the normal boot no figure silent; however, a character display; the boot that is in the standby state, starting with the remote control can not be, after a period of time suddenly start, then hand to control the normal, not normal; remote control; sound normal, no character display etc..QeLservice manual download site
This machine adopts I2C control, the CPU and the functional circuit smell communication should be normal, the machine to normal. Understanding this, very helpful for maintenance. When = the failure or other fault, voltage measured CPU bus SCL1, SDA1, SCL2, SDA2, SCL, SDA each foot value, if the value of voltage between 4.5V~4.8V and the swaying, then CPU in normal work. Then measure the voltage of each function block is integrated circuit I2C bus port value, if the power in 4.5V ~ 4.8V, the bus is working. If a group of bus voltage is low (generally between 2V~3V), the channel has fault, the reason is very simple, is a printed circuit board copper foil breakage or leakage. So when troubleshooting the corresponding port connecting cord on the line (note the interface resistance, port is generally 56 to 100 omega); leakage phenomenon, the copper foil cutting, and cords together can. The hand control normal, not remote fault is receiving head to the CPU integration block line leakage; figure sound normal, but no character display is pulse to Q1215 ask connection fault, according to the above method to find corresponding terminals, cord connected up.

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