NO PICTURE. SOUND OK. FOUR BLINKS TO STANDBY LED AFTER SWITCH ON [SONY WEGA SERIES KV-HA & KV-HW SERIES TVs]

NO PICTURE. SOUND OK.  FOUR BLINKS FO STANDBY LED AFTER SWITCH ON [SONY WEGA SERIES KV-HA & KV-HW SERIES TVs]

     Set switches ON and the standby light at its front panel blinks four times, and switches OFF.  This repeats each time switch ON the set. The fault is with its vertical output section.  This model sets has Bus chassis, and a self diagnosing circuits in the system control section always look into other components’ functions, and if a malfunction is noted, the main system control IC will send a stop signal to main power supply regulator section, stops it to prevent further damage.

     The most common fault found with this type of four blinks and shut down, is due to loose solder terminals at the Vertical Output IC.  This IC [AN 5512], will heat up to an extent, screwed on to a metal heat sink to radiate heat from it while it works.  Repeated heating and cooling might make the solder terminals to this IC to get loose contacted. Normally, these loose contacts are very difficult to detect, they will be microscopic in dimension.  It is a good practice, that suck out the solder on all solder terminals of this IC and resolder it with fresh solder.  This must solve the problem.  Failure of this IC is very rare.  Check this power supply rail too.  It is powered at its pin number (2) and (4). The voltage applied is [+13VDC] at pin number 2 and [-13VDC] at pin number 4.  These voltages are generated and supplied from Line Output transformer pins (7) & (9) respectively.