PUT IT ALL BACK TOGETHER
This should just be a reverse of what we just did, so I'll go though
the steps just highlighting the more delicate aspects.
Now the detector card is again secured to the box, so you can put it back
in the tilted position, resting on the tip of the snout.
Slip the detector card back into the box, with the detector facing the
front. Again, be careful with the thin wires as you do this. It is ok to
let the front of the detector card rest against the inner front of the
box, nothing will touch the detector.
Place the G10 plate+cold straps above the hole in the box and tie the lower
strap to the cold finger. As mentioned in (5-d), this is awkward but just
be patient. Make sure there is a good flat, tight contact with the cold
Put back the four screws 1-4 of Drawing 4. Reverse of (5-c). For the first
screw you put in, you'll have to be well centered and feel the back of
the detector card for the correct hole, then the others go in easy.
Put back the screws A-D of Drawing 4. Reverse of (5-b). Make sure you make
the correct choice among the 4 sets of 4 holes at each corner of
the box, so that you end up with the correct quadrant aligned on the optical
Ok, now we just have to put the dewar back together.
Attach the upper cold strap to the box.
Group the cu-c wires nicely at each corner of the box, so that they all
fall inside the small grove in the box. Put back the box cover. Do this
carefully so that the cover does not pinch any of the wires. Screw
the cover in after you are satisfied that all the wires are clear. With
some double-sided sticky tape and aluminum foil, make new little squares
like the ones you removed in (4-a), and place them over the groove in the
box that lets in the thin wires, so that the box remains light tight.
Slip the box assembly back into place through the rectangular opening of
the lower shield. Again, watch the wires in the cross-brace connectors
as you lower the box. Also, don't leave behind the
output wires. Set the box on top of its four holes in the dewar bottom
Secure the box to the bottom of the dewar. Be sure to center it well so
that the snout end is WELL CENTERED with respect to the dewar bottom plate
(for good optical alingment later). Make sure that there are no wires under
the cross-brace feet before you tighten the screws.
Fish out the 4 output thin wires, place them toward the front of the dewar.
Re-connect the DE9 and DA15 connectors.
Re-connect the outputs of the current quadrant to their input at the amp
board. Match the labels on the wires with those on the amp card. Use small
pliers to make a good connection between the male and female pins.
Re-connect the spare outputs to the dummy socket.
This is a good time to think if you have forgotten some crucial connection.
Clean the o-ring groove in the dewar bottom plate. Clean and re-grease
the o-ring. Put the o-ring in the grove. Do this same cleaning-greasing
on the lower dewar shell and put it in place, with the window facing in
the right direction. Make sure that the shell does not pinch any of the
wires inside the dewar.
Align the support plate, bottom dewar plate and shell and screw them back
together. Go around the screws turning each only a little, until they are
Put the filter wheel shaft back in place. Tighten the outside screw.
Clean the surface of the upper dewar half (which should still be sitting
upside down on the aluminum ring) that is going to be in contact with the
o-ring in the bottom half. Gently lift and turn the bottom dewar assembly
over the upper half, use the 2 aluminum blocks (as in (1-b)) to leave a
gap between the 2 halves.
Re-connect the 2 cold straps to the cold plate. Make a flat, tight contact.
Remove the al. blocks and lower the bottom half. Center the rims of the
upper and lower shields well. The two shield should push against each other
and the lower shield will be somewhat compressed. The front end of the
snout should touch the circular opening in the lower shield.
Screw the 2 halves back together. Go around the screws turning each only
a little, until they are all tight.
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