LG 50PK550 no pic but has sound

[jason424]

This set would have pic for a while then the pic goes out and just sound. Eventually the set would turn itself off. Sometimes the pic would come back for a while, sometimes just the sound. And now nothing.
With the TV on, I tested VA and VS and they seem OK at 59 and 203 but I get really low numbers on the VSC and VY on the YSUS....3 and 2.8 respectively. The cable is delivering 59/203 to the YSUS.
I also checked the connector from the power board to the ZSUS and all the pins going out show:
NC: 5
NC: 5
NC: 0
NC: 0
NC: 0
GND: 0
GND: 0
NC: 0
VS: 203
VS: 203

I do have green blinking LED (1 long, 1 short) on the inverter board below the power board.

Any help on what else to test to narrow down if it's YSUS, ZSUS, power or combo?

[Hamie]

Re: LG 50PK550 no pic but has sound

Run test patterns on the control board with the lvds disconnected.

Good patterns = bad main av board.