identification of lego set by color and shape of inner box
The only 1984 set with corresponding dimensions seems to be 6080 King's Castle but I can't find any picture of a possible inner tray; and that's even assuming it had one (the box picture on this classic-castle forum post seems to point to the contrary).

There's another good candidate in 1985: 6392 Airport, but again I can't find any pictures of the box.

1983 brings us 6980 Galaxy Commander for which I can't find pictures of the inner tray either (but there's one on eBay where the seller promises pictures in the near future); 7824 Railway Station is close too but it's a bit too short I had it and I don't remember it having a blue tray (I'm fairly confident it was red).