TCL color TV 2139A power + B peak capacitor desoldering causes character jitter and tailing - appliance repair

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Fault phenomenon: TCL color TV 2139A character jitter, and tailing. But sometimes it is normal. (It seems to be a suitable point for drawing)
Fault analysis: Sometimes it can be normal, the fault should be the de-soldering of a component, there are few components related to characters, character oscillation, line pulse, field pulse, and CPU.
Repair process: This machine CPU is 87CM38, 28 feet, 29 feet are character shock feet, 26 feet 27 feet are line pulse and field pulse, so the CPU is re-welded, and Q004 and Q005 are related to the line pulse. Solder joints. Plug in the power test machine, the fault remains.
Measuring 26 feet 4V, 27 feet 4.5V, 27 feet 4.5V, 28 feet 4.5V DC voltage should be normal, (this data is also measured after repair) can their pulse is normal but can not be judged, but from the characters of the image Look, the pulse should be arrived, will it be Q004, Q005 performance is bad? The breakdown of these two components will result in no characters. It has been encountered many times before, but the fault is still the same after the replacement. This simple fault has no clue, is it CPU?
At this time, another user sent a 21-inch Changhong. I moved him to the side, first repaired Changhong, repaired Changhong, and plugged in the test machine.
Haha. This plugged me to find the fault of the TCL, because I put the two TV plugs together, I inserted the Changhong, but plugged the TCL TV, and looked up the peak of the TCL circuit board switch transformer when looking up. The capacitor has a slight ignition. The position is field rectification. Is the ignition causing the field power supply to have a pulse, and the CPU field pulse is abnormal?
But take a closer look at this peak capacitor C830 is B + rectified, the field power is powered by the high voltage package. Soldering C830 fault disappears.
In order to find out whether other TVs will have this phenomenon, I tried it on the newly repaired Changhong TV (the field power is powered by the switching power supply), the human interference B+, the characters are clear, but there is still a very light character shifting carefully. For a moment, there is no tailing phenomenon, interference with the field power, the characters are clear and stable. (It may be that the field supply voltage is low and the interference pulse is not enough to affect the characters).
The peak capacitor protects the rectifier when it is turned on and off on the TV. Its presence or absence has no effect on the character, but it causes the fault due to off-welding and sparking.