Toshiba Regza "blink"

The LED on the left blinking green 3 times is power-up, the LED on the right blinking green 3 times is what Toshiba calls a "BUS Error" which basically means a hardware fault.
Credit...
10/08/2015 by Bill Wessendarp

Inverter board issue.

Most likely the power supply board needs to be replaced. It could also be the T-con board or less likely the display itself.

If you don't know what you're doing, DON'T OPEN THE TV UP TO FIX IT, THERE ARE HAZARDOUS VOLTAGES ON THE POWER SUPPLY BOARD, EVEN WEEKS AFTER THE TV IS UNPLUGGED!

If you don't know how to do it yourself, find some local Electronic repair shops, get quotes, try to find reviews on the shops.

Visit the site named 'Electro-help' for more details. Click this link. View it in "Timeslide" option, which can be selected from the drop down box menu by the [Sidebar] tag, at the top left corner of the display window. It will make search easy. There are more than 1000 posts to different brand TVs now. Pull up older posts there.

not sure if this link will help you out but have a look. Toshiba Regza 42 Black Screen Google Search

try resting your tv. power off it press and hold av select botton and then power on your tv wait few minutes and it will rest your tv.... if not used the same wy holding menu botton instead.

I suggest you do firmware update first, then you can use another source such as a DVD plug in to the same HDMI input when the problem appear, to make sure where is the problem, if it is the on the TV, replace the main board.
Part # 75012465 cost approx $300.

Knowledge obtain from: Repair experience on same symptom.
Parts reference: Andrews electronics, 800 289 0300.

Get in touch with your cable company

They see problems like this all the time

Those blinks are fault codes. To know more visit the site linked here. http://electronicshelponline.blogspot.com/

No new video card required. I just reset the television by holding the on/off button for five seconds (yellow light on front panel blinks repeatedly). I then cycled power using the remote control and my picture came back. Worked for me. Hope it works for you.