DEIMOS
CCD SDSU Leach Card Remove/Install Procedure

Background

This document descibes the procedure for replacing an SDSU card from the DEIMOS science CCD controller. It should only be completed by a qualified WMKO Instrument Engineer/Technician.

Required Equipment

Before heading up to DEIMOS, collect the following tools and items:

Procedure

Removal Phase

  1. Shutdown CCD crate. Shutdown the DEIMOS science CCD crate as described in this procedure.
  2. Rotate DEIMOS. Set the DEIMOS handle paddle to manual control and rotate DEIMOS so that the DEIMOS Science CCD controller chassis and its power supply chassis are accessible. The Science CCD controller chassis is located in bay 9 of the DEIMOS electronics ring and its power supply chassis is located beside it in bay 8. Note that bay 9 is also the bay that has the dewar LN2 fill port. (For a diagram of what items are located in what bays, see DEIMOS Electronic Ring Layout).
  3. Set band brake. Once you are at the proper PA for access, set the DEIMOS rotation band brake to ensure that DEIMOS can't rotate.
  4. Remove access panels. Remove the rear-facing panels (i.e., the panels on the side of the electronics ring that faces away from the telescope) for bays 8 and 9. For a picture of what the science controller and power supply chassis look like mounted in the DEIMOS electronics ring, see this photo.
  5. Verify dewar power off. There are four green LEDs on the bottom left corner of the front panel of the DEIMOS Science controller (in bay 9) which indicate whether the various supply voltages are present on the controller backplane. (Note: these LEDs might be taped over with black optical tape, so you may need to temporarily remove the tape to inspect the LEDs; if so, please replace the tape when done.) From left to right, these 4 LEDS are: +5, +16V, -16V, +35V. (See image in DEIMOS CCD Controller web page.) The rightmost 3 of these LEDs (i.e., the analog power supplies +16V, -16V, and +35V) should now all be off. If they are, proceed to the next step. Otherwise, contact Santa Cruz.
  6. Turn off controller power. On the bottom left corner of the front panel of the DEIMOS Science CCD controller, the only green LED that should still be on is the one for the +5 volt digital power. If that is the case, then locate the black rocker ON/OFF switch on the front panel of the Science CCD controller power supply chassis in bay 8 and switch it to the OFF position. This should remove ALL power from the Science CCD controller, and all of the green LEDs should now be off. If not, then contact Santa Cruz.
  7. Don strap. Attach the static strap to your wrist and clip the other end to a ground point on the CCD controller chassis.
  8. Locate the video processing boards [TBD: add map of all the boards indicating which ones control which CCDs.]
    1. There are 14 circuit boards along the bottom row of the Science CCD controller. (Again, see image in DEIMOS CCD Controller web page.)
    2. At the right-hand end of that row are some DC power test points.
    3. Counting from that right-hand end, the first two boards are clock generation boards that have wide flat ribbon cables that connect to DB37 connectors on their fronts.
    4. The board that is third from the right end is the video processing board for CCD 1; it has a narrower flat ribbon cable that connects to a DB25 connector on its front. The other end of that ribbon cable connects to a connector on the top row of the controller; that connector is labeled "Video 1".
    5. The video processing boards for CCDs 2 and 3 are the two boards just to the left of the video processing board for CCD 1. Thus, they are, respectively, the fourth and fifth boards from the right-hand end. The ribbon cable for the video processing board for CCD 2 connects to the "Video 2" connector on the top row, while the ribbon cable for the video processing board for CCD 3 connects to the "Video 3" connector. (Again, see image in DEIMOS CCD Controller web page.)
  9. Remove SDSU board. Making certain that your anti-static wrist strap is still attached to the controller chassis ground, next perform the following sequence of steps to remove the appropriate video processing board.
    1. Remove the two coax cables that connect to the top front of the board via SMB coax connectors. These are snap on/snap off connectors (no threads); simply pull straight back to remove.
    2. Using the "split-bladed flathead" (or "screw starter") screwdriver, carefully remove the two flathead screws that attach the ribbon cable's DB25 connector to the bottom front of the board. Be certain that the screwdriver has solidly captured the screw head before attempting to remove the screw. A dropped screw inside the electronics ring can cause significant damage when the instrument rotates.
    3. Unplug the ribbon cable's DB25 connector from the circuit board.
    4. Using the small, fine point screwdriver, loosen the small captive screws that hold the protective clear Plexiglas cover on the front of the board. Once these screws are loose, carefully remove the cover by pulling it straight back.
    5. Attach the "Gen II SDSU video processor board extractor tool" to the male DB25 connector on the front of the board by screwing its two screws into the mating threaded stand-offs at the top and bottom of the male DB25 connector.
    6. Grabbing onto the extractor tool, pull straight back to remove the board. Note that the VME DIN connector at the back end of the board (which plugs into the VME backplane) fits quite snuggly, so some force is needed to get that DIN connector unplugged from its mating connector on the backplane. It may help to gently wiggle the board up and down at the same time you are pulling straight back with the extractor tool. Once the DIN connector releases from its mate on the backplane, the board should be easy to pull out the rest of the way.
    7. On the solder side of the circuit board, there should be a board serial number that was written using a black marker. The serial numbers are either 2 or 3 digits and are preceded with the letters "SN", e.g., SN 123. Locate the serial number for this board.
    8. Take one of the empty anti-static bags and place the circuit board in that bag. Record on a PostIt note (or perhaps some more permanent type of label) the serial number of the board and the slot from which it was removed, and affix the label to that anti-static bag.
    9. Put the anti-static bag containing the board into your box of things to take downstairs.
  10. Repeat preceding step as needed to remove additional SDSU boards.

Installation Phase

Steps to take once you return to DEIMOS.
  1. Don strap. Attach your anti-static wrist band and connect it to the ground connection on the CCD controller chassis.
  2. Locate boards. Locate the anti-static bag containing the video processing board(s) to be installed.
  3. Install board.
      Insert the board into the appropriate slot in the controller chassis. Make sure the board is aligned with the guide rails. It should slide smoothly back into the slot until its VME DIN connector contacts the mating DIN connector on the backplane. At this point you should push inwards firmly on the DB25 connector on the front of the board until you feel the board firmly seat into the slot as the two DIN connectors completely engage.
    1. Replace the clear Plexiglas cover over the front of the board and screw it into place.
    2. Attach the female DB25 connector on the ribbon cable from "Video 3" to the male DB25 connector on the front of this board.
    3. Using the "split-bladed flathead screwdriver", insert the size 440 screws into the female DB25 connector and screw them into the mating threaded stand-offs on the male connector on the board. Make certain that you have firmly captured the screw head with the screwdriver before attempting to insert the screw.
    4. Attach the video coax cables to the SMB connectors on the front of the board. The coax labeled "A" should attach to the connector on the top of the board, and the one labeled "B" should attach to the connector below it. These are snap on/snap off connectors (no threads); simply align the coax connector with its mate on the board and push it on.
  4. Repeat steps. Repeat preceding steps as required to install additional boards.
  5. Inspect controller. Do a final inspection to the front of the CCD controller to verify that all of the cables and connectors are properly connected.
  6. Reveal indicators. Temporarily remove any black tape from the four green power status LEDs on the lower left corner of the CCD controller front panel.
  7. Restore power. Locate the black rocker switch on the front panel of the science CCD controller power supply chassis, and switch it ON. The green +5V power status LED should come on.
  8. Power up CCD crate. Complete powerup sequence on the DEIMOS science CCD crate as described in this procedure.

See Also

Go to: DEIMOS Home Page - Instruments Home Page - Keck Home Page
Last modified: Tue Sep 29 14:05:09 HST 2009