Toshiba 46 inch regza yellow light blinks and picture wont come on but I have full audio

Inverter board issue.

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 stage 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, to many popular brand TVs and other devices. Viewing it in "Mosaic" will make surf easy.
http://electronicshelponline.blogspot.com/
Blinking codes details to many popular brand TVs are given. Surf the site with patience.

seems like capacitor problem, chack them and if thay have exploded replace them.

Toshiba Regza 37in - 37HL17
TV will not turn on - Yellow power ind. Light blinks three times...
Fixed with a firmware update (hard to believe, but true). Search Google for a file named: 2007SEN069.zip (don't worry if the page you find it on doesn't mention the 37HL17 - it worked fine). Unzip the file, and copy the 3 folders and 3 files to the root of a small SD card. The SD card MUST be 2GB or less in size (I used a 1GB card), and it MUST be formatted with FAT-16 (not FAT-32). Mine was pre-formatted as FAT (FAT-16). The SD port is on the back of the TV behind a cover plate near the power cable. You do NOT need to remove the back cover of the TV, just the small cover plate (1 screw). UNPLUG the TV; remove the cover plate; insert the SD card (prepped as explained above); Plug in the TV; Watch the yellow lights blink, then turn blue, then go dark; UNPLUG the TV; remove the SD Card and replace the cover; Plug in the TV; Yellow lights will blink a few times (this is normal); when blinking stops, turn on the TV and you should be good to go. :-)
Pictures attached are from a Toshiba software upgrade bulletin I found online.

Check your power cable. Unplug it from both ends and plug it back in

I followed the steps at the following link and it worked for me. I have a 2007 Toshiba Regza 42HL67, but the firmware applies to many models as documented in the readme file at the location found via the link below. I used a 1gb SD card formatted FAT16, copied the unzipped files and folder to the card (wasn't sure if it required the top level folder or only the files under the top level folder so I copied both to the root of the SD card), unplugged the TV, inserted the card, plugged in the TV, waited 2.5 minutes, unplugged the TV, removed the card, plugged in the TV, yellow light flashed 3 times and went out. I turned on the TV and it has worked normally since last night.

http://www.benjammin.net/www/pages/techtips/Toshiba-Regza-42HL167.html

Ur tv been in use at least 1 1/2 or 2 years.On about 4 or 5 hours a day on this tv?The LED light indicator "LAMP" flashes?The projection bulb life is over.Require a new bulb.

Toshiba Regza 37in - 37HL17
TV will not turn on Yellow power ind. Light blinks three times...
Fixed with a firmware update (hard to believe, but true). Search Google for a file named: 2007SEN069.zip (don't worry if the page you find it on doesn't mention the 37HL17 - it worked fine). Unzip the file, and copy the 3 folders and 3 files to the root of a small SD card. The SD card MUST be 2GB or less in size (I used a 1GB card), and it MUST be formatted with FAT-16 (not FAT-32). Mine was pre-formatted as FAT (FAT-16). The SD port is on the back of the TV behind a cover plate near the power cable. You do NOT need to remove the back cover of the TV, just the small cover plate (1 screw). UNPLUG the TV; remove the cover plate; insert the SD card (prepped as explained above); Plug in the TV; Watch the yellow lights blink, then turn blue, then go dark; UNPLUG the TV; remove the SD Card and replace the cover; Plug in the TV; Yellow lights will blink a few times (this is normal); when blinking stops, turn on the TV and you should be good to go. :-)
Pictures attached are from a Toshiba software upgrade bulletin I found online.

May have a bad lamp. Check the troubleshooting part of the manual. It will say if the red led is blinking, then check lamp.

Toshiba42 lcd lost picture