Saturday, April 28, 2012

SONY WEGA SERIES PIN CUSHION DISTORTION repair KV-HA and KV-HW SERIES

The vertical lines on the right and left side of the TV will look somewhat bend inside, and the width of the picture will be less; somewhat distorted picture.



The pin-cusion [East-West] amplifier output section has the fault. 

Check and replace two pin-drive transistors [Q850 - MSD 601-RT1(NPN TYPE); Q851 - MSB 709-RT1(PNP TYPE), & Pin output FET Q802.  Replace zener diode [D805] too. Check the voltage at the collector point of Q850.  It should be around 8.5VDC.  Never attempt to measure the voltage at the source of the FET.  The multimeter might be damaged.

If this do not help you, replace the two ICs used there [MC4558CD & NJM2903M].  Bothe ICs are easy to get from most of the electronics spare part shops, and are cheap to buy. 
When replace the FET at the pin output section, be sure to make a it tight with its heatsink.  apply heatsink compond to get good heat transfer.