This machine in the plug or swinging inserted into the high-frequency head antenna plug, the fault can be temporarily disappear and appear. Thus doubt the high frequency signal input terminal belonging to the welding on the surface of the head (actually this is also a failing). But as did not open welding, replace the high-frequency head failure still (actually plug or fiddling with the antenna input plug resulted in vibration in the circuit board). And he suspected antenna input plug where there is a poor contact. But even if to replace the new antenna plug (including lead) also of no help. Now just know, fault point should be on the circuit board has a poor contact. Next found hovering in the vibration when the printed circuit board fault, when the printed circuit board inserted into the slot and then to a component (such as switch transformer) force filed a short distance to make printing plate upwards slightly bent, failure can disappear.
 
And he suspected fracture in the circuit copper foil. After many lookup failed, only under the PCB pad a disposable plastic cup bottom is up slightly bent, keep watch. Who knows that only lasted for more than a month, fault recurrence again. The find even if like this will floor also is invalid, but the floor vibration fault is hers.
 
Is difficult, I suddenly have a thought from my mind flash across: since failure is caused by poor contact and scope and the signal channel part, why not check signal channel compenent solder repair welding? Then follow the signal to the first high-frequency head for the nearest image/sound into the integrated block IC101 pin solder one by one (AN5138NK) to add tin after welding of commissioning, troubleshooting.