Jigzat, according to the ribbon number yours is a iMac (21.5-inch, Mid 2010), is that correct? 922-9497 593-1280-a 593-1280 are compatible data display cables for that model. Now in order to find the proper display port connector, it will help to either know the mother board number (should be stenciled on your board) and/or the display panel number. This is important to try to match it. If fourth LED is not visible after power on:
• Verify internal DisplayPort cable connections between LCD panel and logic board
• Inspect LCD display cables for cable damage
• Verify external video functionality, and according to result check the following items:
If external display works then verify/replace the LED backlight board
If external display works then verify/replace the LCD panel
If external display does not work verify/replace the logic board