hi,
1. The main causes of video blanking are: IK problems
• G-2 voltage missing or improperly adjusted
• Missing filament voltage
2. Defective Y/C Jungle IC
3. Loss of vertical drive signals
4. No data to Y/C Jungle IC
Servicing the unit , requires a
Sony KP-61V90 Service Manualonly with a fee
It would be best , to give me more details about your TV, ( Model,
chassis number )
the things you have done ,
and the part number of the IC s you have replaced
If you need further clarifications , don't hesitate to ask,