Hello there and welcome to Just Answer. My name is XXXXX XXXXX I will be assisting you today. I am an engineer with over 30 years of electrical and electronic training, repair and installation experience. I will try and answer your question accurately and precisely so that we can get you on your way.
Turn just the TV on. Using the Sony TV remote (not the cable remote) press MENU.
Do you get a menu on the screen.
Also, can you look behind the TV and get me the full model number? It will begin with a 'K'.
Please let me know so that we can continue.
Ok, with the Sony remote again, I want you to try and turn the brightness or the contrast up as far as it will go. You may not be able to do this beciase of the lack of indication on the screen.
Let me know if you can't do that.
If you can, let me know if you see anything form the screen - raster lines, little bits of snow, flickering etc.
I'll be here.
Then it does sound like the TV is not displaying a picture. You have no menu and no screen controls - in other words, no on screen display.
This has nothing to do with your cable box since these features are generated inside the TV itself.
If this is the case, are you getting a blinking red LED on the front of the TV?
Now...the red LED on the front of the set will blink in a repeating pattern. Can you tell me how many times the LED blinks between the short pauses? For example: 5 blinks, pause, 5 blinks, pause etc.
The most likely failure here is with one or both voltage regulator ICs on the D board. These cost only a few dollars but soldering is required.
To have this repaired by a shop is going to run you about $150 if you take the TV to them. It is a very common failure.
The ICs are type MCX3001D: http://www.ebay.com/itm/2pcs-MCZ3001DB-MCZ3001D-MCZ3001-IC-18-PIN-SOCKET-/330540061757
If you can do this yourself, I will help you. If not, you can find a tech in your area at www.tvrepairpros.com
I'm sorry that there is no quick and easy fix for this problem.
I'll be here if you need further help with this issue. Please let me know.
Phillipa, I can only give you the most likely failure based on your symptoms but I can assure you that this is a very common problem on this TV chassis.
I'll leave the decision on my compensation in your hands and I'll be here if you need further assistance.