MINOS

Plane 107 - On the west LEDs 1(left) and 19(right) appear to be swapped (ashtrays: 20 and 18 in LIM 8)
This is for run 5900 - made around Jun 27.

Now for the fun part... We DELIBERATELY changed fibres 18 and 20 around on Plane 107 West in the hope that it would either solve the problem or at least show us where the problem lay. The result was...

Exactly the same!
There are no changes on any of the other LEDs in the plane either...
There was a chance that there was a discrepancy of one plane between the codes' planes and the real planes.
But this graph shows a plane either side of 107 and East and West - there is no difference seen anywhere!

So what can I conclude from this. Well...
A connection with mux box recabling has since been excluded as a possible cause.
It is possible that the mine crew put the cables back in the right place instead of swapping it over - I'd like to treat this as highly improbable.
The code is looking at the wrong bit of the detector!

So what's our brilliant soulution to the problem...let's fiddle around some more!
So we changed 18,19,20 on Plane 42 West to 19,18,20.
Let's see what happened...

Before (run 6059)

After (run 6101)

Woo Hoo!
Pardon my french but: thank fookin God!