Toshiba 46ZV555DB, BLACK SCREEN WITH BLUE BAR ACROSS THE TOP, NO SOUND

SOURCE: power led blinks but no picture or sound

Had the same problem myself. Took some doing but I managed to find a service bulletin that I downloaded. The problem is with the siene module and all you need to do is unplug connector JP63A from the main board and your TV will work again.
Take the back off the TV (there are a lot of screws) and look on the left hand side of the main circuit board that is mounted in the center of the TV. You will see a small white connector that is labelled JP63A, simply unplug it. Plug the TV back in and let it reboot. That's it, should be able to watch immediately.

SOURCE: Toshiba 50HP66 Blank Screen with sound

I would suggest to read what other members have reported by clicking here.
Good Luck.

SOURCE: Toshiba 50hp66

I think that the pop you heard was an electrolytic capacitor blowing its top on the picture frame board. If you are able to check this for yourself by looking on the board for the one/s with a bulging top or are a brownish/black colour like something has caught fire. And also in this situation smell can be of great help as it will smell burnt out but PLEASE before putting your nose or anything else in the tv take all necessary precautions against electric shock and discharge any electrolytic capacitors in the vicinity. If you are not able to do this yourself find a competant technician. Hope this helps.

SOURCE: Green light but no picture, no sound

Your mainboard is damaged, replace it and that will solve your issue.

SOURCE: red dots like

If they are moving, it is a Random pixel discharge. This can be caused by 3 different problems, that are not easily diagnosed through a chat like this. 1. I could be a miss adjustment of critical voltages that control pixel discharge in the set, although i have not looked at your set in particular, some models are automatic and don't have an adjustment. 2. It could be the x board or equivalent, 3. It could be the panel it's self.

in my experience with this problem the adjustment rarely fixed the problem, more likely the Panel is failing, although sometimes the x board will cause this issue.

I am sorry I cannot get you any closer than that, I recommend getting a repair tech out to check it out. This set is repaired by replacing boards not component level, the boards can be expensive and I don’t want to recommend a board replacement unless I was the tech to actually see the problem.