The owner of a Sony TV with model number KV-25JXR20 complained of the reduced horizontal width of the picture of his TV. He also observed "blinking" of the picture which must be his description of intermittent blanking of the picture.
During my initial observation of the problem I also noticed that the vertical size of the picture is in overscan - or stretched - resulting to vertical mislinearity and the presence of red, blue and green blanking lines at the top edge of the picture.
I suspected capacitors with changed values in the vertical deflection circuit and the horizontal deflection or pin correction circuits. Since the TV is already in the vicinity of being ten years of age, I also considered the possibility of dry solder joints.
Since there was no obvious bulging capacitors in my initial inspection of the main PCB I proceeded to resolder the deflection circuits and some parts of the chopper transformer, filter capacitors and rectifier diodes in the secondary circuit of the power supply.
After the soldering exercise, I powered-up the TV again to check if the problem was solved. I was not much surprised to see that the problem still persists since there was not really any obvious cracked or dried up solder joints on the TV's circuit board.
Doing another visual inspection on the component side of the PCB, I noticed the slight bulge on the top of a filter capacitor that was sitting beside the chopper transformer. I desoldered the capacitor and found out that it is a 100uF/160V electrolytic capacitor on PCB location number C609. A look under the capacitor revealed signs of electrolyte leakage. With the capacitor leads still hot from contact with the soldering iron I can still see the electrolyte boiling out of one of the capacitor leads.
By replacing this capacitor only, I was able to solved both the problem with reduced horizontal width and vertical mislinearity.
