Hello!

I had a very tedious day at the test stand!  I have identified a few different failure modes:

 -> bent pins on TAB/GAB backplane.

 -> cable fails because one of the four "layers" that make
    up the connector comes apart.  In at least one case I was
    able to "repair" the cable by snapping this layer back into position.

 -> cable fails for unknown reason.

 -> a TAB with appararently two bad LVDS receivers

 -> an intermittent problem, that *may* be on ATCs, that I haven't
    carefully investigated yet.

As these cables are failing, we should get many spares.

I have worked carefully through the center cables of the first 6 TABs.

 -> there are three bent pins, which I have not yet tried to fix.
    One is close to the GAB slot, which I will repair first since there is
    reasonable access.

 -> there were several bad cables, which I have replaced with success.

 -> there is one cable which needs to be replaced, but I don't have a
    spare for it.

There are two more TABs for me to work through, which have four problem cables, two of which might be bent pins.  And then there are the A and C type cables (overlap regions).  I have gotten much faster at diagnosing problems and am ready to start a more streamlined approach, which will not attempt to replace bad cables, just diagnose them.

I have seen with software, but not yet investigated carefully many other problem cables.  Here is the complete list of problem cable/chips.

bad central cables (4x4 region):
tab(1-8): chip(0-9)(count)
tab 0:  8(16)                       (bent pin, cable unplugged => 16)
tab 1:  8(16)                       (bent pin, "")
tab 2:
tab 3:  2(16)                       (bent pin, "")
tab 4:
tab 5:  8(16)                       (cable? pins look fine)
tab 6:  3(1)  9(3)                  ...as far as I got...
tab 7:  0(3)  7(1)  8(2)
total bad channels:  74
bad left cables (2x4 region):
tab(1-8): chip(0-9)(count)
tab 0:  4(3)  9(1)
tab 1:  8(8)
tab 2:  0(8)
tab 3:  7(8)
tab 4:  5(5)
tab 5:  0(7)  5(1)  7(8)
tab 6:
tab 7:  1(4)  3(1)  8(2)
total bad channels:  56
bad right cables (3x4 region):
tab(1-8): chip(0-9)(count)
tab 0:  9(1)
tab 1:  1(12)
tab 2:  3(12)
tab 3:  2(3)
tab 4:  0(5)  8(1)
tab 5:
tab 6:  0(3)
tab 7:  1(3)  8(12)
total bad channels:  52

cheers,
mike