Macbook Air Boots but black screen

Dear all,

Trying to troubleshoot the black screen issue on my macbook air 11 inch Mid 2013 model A1465, 1.3GHz i5 processor with 4GB mem and Intel HD Graphics 5000. Mac OS High Sierra -10.13.4 (upgraded to this OS after the problem first happened to see if upgrade may help but it didn’t)

Symptoms are as follows:

• Macbook boots (get the chimes) keys on the keyboard light up – screen black no cursor
• No faint image on the screen (tested in dark area and shone a light to look for a faint image)
• Camera works fine
• External video connection via mini display port works fine.
• Go into system preferences can only see my Dell external monitor, by pressing the Optionkey to ‘detect displays’ provides no additional displays (looking for an Internal Display)
• Go into About This Mac and select System Report and check for graphics/display, I can see the GPU and the Dell screen but no internal display.
• After running the diagnostics on the Macbook, had the error: VFD004 and VFD001 to which Apple translates as: ‘There may be an issue with the display.”
• F5 and F6 keys work ok and I can see on the external monitor the scale of which the backlight is being increased or decreased by the F5 and F6 keys, however the same does not happen with the F1 and F2 keys, they do not appear to work.
• Apple logo on the lid does not illuminate

Things tested to date:

Have tried but to no avail:

• Reset System Management Controller (SMC)
• Reset Parameter RAM (PRAM)
• Re-seating the LVDS cable on the logic board
• Upgrading the OS
• Booting into Single User Mode
• Pressing the black hinge between the lid and the laptop

Have ruled out the following:

• Don’t think it’s the graphics card as the external display works fine.
• Don’t think it’s a backlight issue as the screen is completely black, no faint display at all and no logo.

So I guess it has to be either the screen or the LVDS cable that needs replacing however as the next steps seem rather drastic like removing the bezel from the screen to get to cables etc. I wanted to try and identify the faulty piece of equipment, as such I thought I’d check with all you gurus out there to see if there’s a consensus on what the problem may be or if there’s something simple I’ve missed. Happy to get the multi meter out and start checking internals, I don’t however have any schematics for the Macbook Air and I wouldn’t know what tolerances to look out for. Any help greatly appreciated as this has been a really nice piece of kit until now.