Checking TMS Cables For Shorts

If this story sounds familiar, it's because it sort of is.  On 1/23 , I checked all the TMS cables/runs for any shorts between ALL wires, but I didn't check for shorts between the Shield and Ground (Filiberto/Betsy did this for their cables on 1/30 , and happened to check some of our cables and found a short with one of our cables).  Today ALL TMS cables were checked for shorts between Sheild and Ground (Betsy assisted).  Shorts to ground were found in (2) Cable Runs:

1)  TMS SUS (F1, F2, F3, Side) Cable Run

Found the same short Filiberto & Betsy found.  We disconnected cables at Cable Bracket on the Optics Table  & short went away, so pointed blame to the SUS quadrapuss cable.  So, basically just started looking at cable for any kinks, stray shield "hairs", etc.  It looked dire at first because there was nothing obvious, but eventually found that the issue was the thin copper wire used to tie these cables to the Upper Structure Frame (see photo#1 of this wire at a different spot).  [The end of the wire which wrapped around the structure was poking the Sheild, thus shorting].  We followed what SUS does in this scenario and removed the wire and just stuffed excess cable in the structure beams (see photo#2).  Short CLEARLY ELIMINATED.

2) Picomotor Cable Run

For this one, we were able to trace the short to the "middle" cable which runs from the Table, needles through the Upper Mass, and goes to the Optics Table (this the absolute worst run to have an issue with a cable--see photo#3).  Checked obvious places for problems, but couldn't find anything.  We noticed from the Upper Mass up to the Optics Table was a fairly straight run and the Clamp on Optics Table (see photo#4) was pretty tight.  So this was our best guess at a culprit.  I went ahead and loosened the clamp a little.....

BUT, then the thought of possibly altering alignment entered my mind since I've tinkered with cables connected to our suspended Upper Mass (possibly a "D'oh!").  Anyway, I confirmed this clamp wasn't a cause for the short and did my best to restore these cables/cable clamp.  I then just looked at how the cable hung under the Upper Mass, and this is turned out to be the issue (somewhere between the Upper Mass bottom clamp and the Cable Bracket on the table---this cable shorts.  there's not a lot of slack here so it's probably because it's a little tight).  I was able to move the cable around a little and it managed to stop shorting.  Then I forgot we like this cable run through a Cable Post.  Using this pulled the cable a little tight and caused shorting again (!), after some cussing and magic the short disappeared---we just can't breathe on the cable.  Short SORT OF ELIMINATED.

All other cables should be OK.  I noticed that a pair of cables pinged briefly with a short, but Richard mentioned this is probably a capacitive effect (we'd need to look at the cable to confirm....apparently, some TMS/ISC cables don't follow the LIGO standard for wiring/shield).  At any rate, we called it good and left these cables coiled on Stage-0.

Dressed D1000225 Which Is Replacing Damaged D1000223

Grabbed this cable from the Optics Table and dressed it on the ISI following the path Jim used for similar TMS cables.  Note:  I forgot to screw in screws on connector which connects to in-vac side of feedthru (heads of these screws protruding has been noted to cause shorts).

TMS Balance Masses Secured

One thing we forgot to do after our alignment work from Tuesday, was secure the balance masses located under the TMS Table.  I tightened the Pitch Masses (the Roll set screw was already tight).

Oh, and also took photo of Swing Stop Cart which was installed yesterday (photo#5)