The machine's line scanning drive pulse does not directly drive the line output stage 19.

Analysis and Repair: The horizontal scanning drive pulse of this machine does not directly drive the horizontal output stage, but is driven through a bistable circuit to the horizontal output stage. Moreover, the drive pulse is divided into two paths according to the waveform, separately driving the pincushion correction output and the horizontal pulse output. Then, the two waveforms are serially superimposed before being sent to the deflection coil. After the above analysis, first check IC4301, and it was found that it has normal horizontal pulse output. Then check the horizontal push stage circuit, and when measuring the collector voltage of Q6806 and Q6805, it was discovered that the c-pole voltage of Q6805 is +50V, which is too low. Normally, the collector voltage of Q6806 should be 65~70V, and the collector voltage of Q6805 should be 70±10V. Upon inspection, it was found that the horizontal push tube Q6805 had broken down.

Sony KV-ES34M9S TV model, after turning on, there is no raster, and the power supply is also unprotected.

Solution: After replacing Q6805 with the same model, the fault was eliminated.

Beijing Sony TV Repair Center, organized on August 10, 2011.