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User name R. Michaels
Log entry time 21:04:42 on November 15, 2008
Entry number 249026
This entry is a followup to: 249024
keyword=re: raster repair
There is a call list for raster repair. I'm on the list, probably near the bottom. I can come in
around 10ish if necessary.
Some notes about raster, fit for a wiki if they prove to be correct (my memory may be foggy):
MCC will tell you which has failed -- vertical (Y) or horizontal (X).
Their notation, last time I checked, had to do with the direction of the B field.
So, Y = vertical field (i.e. horizontal deflection). And X is the other way.
If the MCC cannot reset raster, here's what to do:
0. Find someone on the call list to fix it. But this often fails for some reason .... so then do 1
1. First, determine which supply is broken and look at it to make sure you know what it looks
like. Take access, find the raster, follow it's cable to the lead-brick box containing 2 power
supplies. Find the suspect bad supply. If the green LED is off (presumably only on one
supply), then indeed the supply is bad. Why ? All such failures so far are due to a 24V supply,
but since we've changed / improved this design it may or may not be so this time.
2. Find the replacement supply. It may be in EEL building room 126, or perhaps Bill Gunning
has staged it somewhere else ? Note, EEL126 is the electronics lab.
It might also be in EEL 109 (or whatever is the electronics groups main lab.)
(If you don't find it in EEL126/109 you'll need to call Bill Gunning or Jack Segal.)
3. What to look for: raster supplies # 5,6,7,8 belong to hall A and are matched to our raster.
Do NOT use any other power supply box. For example, if you use hall C's supplies they will
probably fail (it's happened) and never mind why. Obviously, two of the above are already
deployed, the other two are spares. NOTE: #6 and 8 are "vertical" (field, see note about MCC
notation), and the other two are "horizontal" (MCC notation).
4. Make careful notes about the cabling, pull the bad supply out, restore cabling exactly as
before, then call MCC while still in the hall and make sure they can ramp up the raster to some
small value like 1x1 mm. If that's ok, ramp up to whatever max you want. If that's ok, you are
done. Exit the hall.