Sounds like it's turning on. The power light goes out and the standby light blinks 4 times and keeps repeating that.

One option to try is to try to factory reset the tv, to do this turn the tv on hold the Down Arrow on the remote and while doing this press the power button then release the down arrow button.

Bit of info on your issue
* Four blinks - No vertical Deflection (V STOP), Screen goes to a single horizontal line then the video signal muted. Check IC1509, Q1505

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These blinks [flashes] are fault indication (Error Codes). From the number of blinks occur at one time switch ON, you can get an idea about the faulty circuit section inside it. This will make repair easy. These are called blinking codes. Make sure about the exact number of blinking of the standby/power LED, by switching On & OFF the set, for at least two times. Count it carefully. If you wish to get some details, check the site linked here. It has details about blinking codes, and fault locating procedure, to many popular brand TVs and other devices. http://electronicshelponline.blogspot.com/
Blinking codes details to many popular brand TVs are given. Surf the site with patience.

Sony eSupport KF 60XBR800 Support This may help

12 blinks of standby light indicates 'Scanrate error'. You must have thorough knowledge in electronics to proceed. Actually, this is not a user repairable fault. it is very skilled work.

• Five blinks - AKB circuit (automatic kine bias), the timer/standby indicator blinks for about 30 seconds then goes to the self-diagnosis function. Something is wrong with the video. Check video out, Q705, 732, 761 and other components on the C board, also check Q218, 219, 220 on the A board. In addition, unit could be in IK blanking, try turning up screen A2 slightly.
  

sounds like the bulb needs to be changed

cant find signal with or without cable box

I think your lamp has had it

6 blinks is usually the D board