MINOS

First 4 planes, Led 1
Top Row = Plane 1 and 3, East
Second Row = Plane 2 and 4, East
Third Row = Plane 1 and 3, West
Last Row = Plane 2 and 4, West

First 4 planes, Led 2
Blue pads show where we expect light
Black circles are where we see light and size shows amount of light seen

First 4 planes, Led 4

So it looks like Led 4 and 2 are the wrong way round in plane 4 west.
Plane 4 uses 'B' type LI connectors (2-20 then 1) so led 2 is actually led 1 and led 4 is actually led 3.
LED's 1 and 3 are in 3-fibre LIM Module 1 on the very bottom of the detector on the west side.
Is this right?

All 20 LEDs in Plane 1 to 4