My toshiba 55g300u sreen went black no picture or sound

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: my toshiba 22cv100u screen is black when I have tv on, i have sound but no picture

your backlight may be out....I working on one with same problem...the transformer on the backlight inverter board went bad, its about 12 dollars on ebay....but in your case, would require some troubleshooting to determine if you have the same problem. there is an access panel on the back of the tv, under that is 4 connectors, they are high voltage out to the backlight lamps. you would need a volt meter to determine if the lamps are bad or the board