How To Fix Certain EMC Hardware Problems
How to replace a LV power supply
Please do this only if directed by the EMC group (commissioner).
and consult Safety Guide
- First make sure the PS really needs to be replaced. (i.e. Is it dead, or is it
just giving strange readings?) Cycle the power using the black button
on the PS (please count to 10 before turning it on). If you're sure the PS needs to
be replaced, proceed to the next step. (Sure sign would be the persistent
- Get a spare power supply from the cabinet upstairs. The spares are kept in the
cabinet on the right-hand side.
(The key for the cabinet door is marked "IR-2 EMC" and located inside the
beige key box right above the first aid kit next to the stationary cabinets
in the control room).
- Turn off the broken PS.
- Pull out the broken PS and replace with new one. The green circuit board goes
on the guide rails.
- Turn on the new PS. Green LED should come alive.
- Mark the broken power supply and either hand it to
the EMC commissioner or leave it at a mutually agreed location.
- If the PS was for a TRB, then wait for the EMC expert for
further instruction (all corresponding IOBs need to be power cycled).
How to replace a UPC ROM
You need to coordinate this replacement with the dataflow group.
Follow the steps below ONLY if permitted to do so by ODF.
- Coordinate your actions with the shiftleader. Give yourself at least 15min for
the critical part (items 3-12).
- Get a spare UPC from the bench upstairs, check it out on the sheet next to the
- Turn off the crate (red switch).
- Disconnect the 3 fibers and the trigger cable.
- Unlock the ROM by pushing ejector handles outward (upper one up, loewr one down).
On some ROMs this may turn out to be a serious workout.
- Carefully pull out the ROM.
- On the new ROM, set the correct address by copying the
DIP switch setting from the one you just removed.
- Insert the new ROM in the empty slot's guide rails and carefully slide it in.
- For the last inch, push ejector handles outward, then press ROM into place.
The handles should tilt inwards a little.
- Now pull ejector handles inwards all the way, pressing the ROM into the crate
at the same time.
- Reconnect fibers and trigger cable. The fibers are color-coded with blue (A),
yellow (B), or no tape (C).
- Turn crate back on. Make sure fans are running at full speed.
- Mark the broken UPC and place it next to the spares, front panel facing the wall.
- Make an entry in the sheet 'Crap UPCs'.
Report the replacement.
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This page is: /BFROOT/www/Detector/Calorimeter/Operations/EMC_HowtoFix.html
Created: Ivo Eschrich
Last Modified: Jong Yi
Last modified: Sun Aug 26 22:35:38 PDT 2007