This is the list of wedges with problems identified by Aaron. Which ones of these is amenable for repair or replacement?
First we'll ignore those with few (<10%) bad channels. Next, on the assumption that we will not disassemble disks from the cages, the only ones that can be replaced are on station 3, #3 and #5 on the list.
Crate ROC Station Sector Chips Channels Percent Disabled
-------------------------------------------------------------
1) NW 5 0 3 10 0 100.00
2) NE 0 2 3 26 0 100.00
3) NE 4 3 0 26 0 100.00
4) SE 2 2 3 26 0 100.00
5) SE 1 3 2 13 0 50.00
6) SE 1 2 3 7 33 27.91
7) NW 2 2 2 3 1 11.57
8) NW 0 0 2 1 3 10.23
9) NW 2 3 2 1 2 3.91 ------------
10) NE 2 1 2 1 1 3.88 Ignore below
11) NE 3 2 1 1 0 3.85 here
12) NE 5 3 1 0 52 1.56
13) NW 5 0 0 0 14 1.09
14) NE 3 3 1 0 35 1.05
15) NW 4 0 2 0 7 0.55
16) NE 0 3 3 0 18 0.54
17) SE 0 2 0 0 14 0.42
18) NE 3 3 2 0 11 0.33
19) NE 5 3 3 0 11 0.33
20) NW 4 0 0 0 2 0.16
21) NE 0 3 0 0 5 0.15
22) NE 0 1 2 0 4 0.12
...
In the table, 'Sector' is the column on the ROC, not the wedge order. This drawing is from here. It shows the mapping between wedge placement and ROC columns. So for #3 on the list, at Sector 0, this is a downstream high wedge.
This one should be easy to replace.
Similarly, #5 is sector 2, which is a downstream low wedge. This means we have to remove 2 neighboring wedges to get access, but this one is also doable.
What about station 0 wedges? This picture shows that after St0 is placed into the cage, the extension cables are not taped down to the cage. So it might be possible to pull out an upstream St0 wedge far enough to disconnect it from the extension cable.
The first in the list is sector 3, which is upstream high. If we can pull it out, we could consider replacing it.
