@bo1 the 5 blink error code can have quite a few different causes. Ranging from the T-con board to the panel and few things in between. If you have the original TV remote than try to see if this will work on your set:
1. In standby mode, press the following buttons on the Sony remote:
2. On the left side are the blink codes. On the right hand side is the error count.
3. Under 005, you'll see three listings... TCON, HFR, and P-ID (panel).
4. Let us know what errors your set shows.
If that does not work on your set, then you will have to remove the back of your TV and check the boards. Try to rule out/in the T-con board as faulty. Disconnect the LVDS cable to the T-CON board, the cable between the Main board and the T-CON board, and see if the error code will change. Let us know what the result is.