TV repair? I replaced the SC board because TV had 7 red blink fault. Now I have sound but no picture. Think board is bad?

Your TV is blinking 7 times is because it is either it is the SC or the SU or the SD board has stopped working or a combination of all three here. . The heat dispersal system and the heat sink have quit working on your TV.

Sounds like main digital board fault. 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://electro-medical.blogspot.com/
http://electronicshelponline.blogspot.com/
If blinks continue without any pause, the main board is faulty.
Search the site by type in the "brand name" to your device, in the "Search box at the top right of the display window of the Homepage" to get gathered related posts.

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/
If blinks continue without any pause, the main board is faulty.
Search the site by type in the "brand name" to your device, in the "Search box at the top right of the display window of the Homepage" to get gathered related posts.

Sounds like power supply regulator board fault. 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/
If blinks continue without any pause, the main board is faulty.
Search the site by type in the "brand name" to your device, in the "Search box at the top right of the display window of the Homepage" to get gathered related posts.

I don't know

7 blinks? Driver SOS 2 SU / SD / SS Boards (SC floating voltage area). These blinks are fault indication, and known as blinking codes. From the number of blinks occur at one time switch ON; you can get an idea about the faulty circuit stage inside the TV. This will make repair easy. For more information, check the link http://electronicshelponline.blogspot.com/. If the blinks continues, and non-stop, the fault should be with its main system control IC, and with the memory IC.

try this panasonic repair link

are you certain its 11 blinks?

A 6 blink SOS shutdown, you would want to be looking at the SC, SU and the SD boards. One of those boards is causing the malfunction. Possibly, but unlikly(I have to mention it for just in case reasons) the PDP panel could have blown those boards.

Just out of curiosity, what was the original problem that made you call the first repair guy?

7 blinks indicates a bad buffer board, usually I replaced the Y board and the buffer/s about $500-600 in parts. but before you buy anything open the set and look at the power supply if you see two capacitors that look swollen , bulging on top they need to be changed and may solve the issue. the power supply is middle top . If you are not wanting to repair it yourself then know that you do have some circuit board repairs needed.
thanks
Eric

I’m happy to help further over the phone at https://www.6ya.com/expert/eric_ab7c09ec01841771