24-Hour Conversion Kit for the Davis Instruments 7747 Daytime Fan

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www.scaledinstruments.com
507 NW 60th Street Suite D Gainesville, FL, 32607 USA
Phone: (352) 262-6119
Email: ryanwilhour@gmail.com
24-Hour Conversion Kit for the Davis Instruments 7747
Daytime Fan-Aspirated Radiation Shield
Table of Contents
Introduction .................................................................................................................................................. 1
Acknowledgements....................................................................................................................................... 2
Components .................................................................................................................................................. 2
Parts List ........................................................................................................................................................ 2
Tools Needed: ............................................................................................................................................... 2
Performing the Conversion ........................................................................................................................... 3
Installation Overview ................................................................................................................................ 3
Remove & Disassemble the existing DFARS ............................................................................................. 3
Move Spacers ............................................................................................................................................ 9
Install Battery Terminals into appropriate slots ..................................................................................... 11
Place the PCBA into the DFARS and Solder battery connectors ............................................................. 13
Reassemble the radiation shield ............................................................................................................. 15
Reinstall the radiation shield to the ISS .................................................................................................. 19
Introduction
Thank you for your purchase of the 24-hour conversion kit used to convert a Davis 7747
Daytime Fan-Aspirated Radiation Shield (DFARS) into a 24-hour unit. This conversion kit is
designed to bring your DFARS as close as possible to the official 24-hour shield used on the
Davis Vantage Pro2 Models 6153 & 6163. The kit utilizes the same parts used in these models
to provide both solar and battery power to your DFARS. This guide assumes you have already
purchased and installed the Davis 7747 unit. Scaled Instruments is not responsible for any
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change in warranty status of your equipment due to the installation of this conversion kit.
Additionally, Scaled Instruments is not responsible for any damage or injury you may cause by
installing this kit.
A portion of this installation requires the ability to solder leads to a printed circuit board
assembly (PCBA). If you are not confident in your ability to perform this step, it is strongly
suggested you contact a friend with the proper equipment and experience to create a good
solder joint.
Acknowledgements
Scaled instruments would like to thank a generous customer who wishes to remain anonymous
for this outstanding guide.
Components
Before starting, please ensure you have all the necessary components for the conversion. This
conversion relies on re-using parts that are already included with your DFARS, so be sure you
don’t throw anything out until the conversion is complete. You should have the following
components shown on the next page:
Parts List
Quantity
Description
(2)
(2)
(2)
(3)
(3)
(3)
(3)
(3)
(1)
(1)
(1)
(1)
(6)
7011.010 24 Hr Spars ISS NiCad Rechargeable Batteries
7342.509 Pro2 Spars 24 Hr NiCad Battery Cover
7354.003 Pro2 Spars 24 Hr NiCad Battery Cover O-Ring
7350.787 PRO2 Standoff M/F #8-32 1.5” Hex 2.25”
7350.015 PRO2 Stainless Steel 24Hr Shield Spacer
#8-32 x 1.25” Stainless Steel Machine Screws
#8 Stainless Steel Lock Washers
#8 Stainless Steel Flat Washers
7353.2034 Pro2 SPARS Red and Black Battery Lead Wire Set
7315.053A Pro2 24hr SPARS PCBA Circuit
7342.514 Pro2 PCBA Cover
7345.119 Pro2 24hr SPARS Solar Panel
#4-3/8” Stainless Steel Self Tapping Screws
Tools Needed:
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•
•
•
A medium Phillips Head screwdriver
A good soldering iron (Capable of reaching 800 deg F) and StayBrite or equivalent
SILVER solder (Do not use Lead-Tin solder due to exposure to elements) – Rosin core
preferred, or non-corrosive flux
Wire stripper
Performing the Conversion
Installation Overview
1. For Consoles – Put the console into Setup Mode to prevent erroneous data while
working on the ISS. To put the Vantage Pro2 console into Setup Mode, press and hold
DONE and then press the down arrow (-). This prevents the reception of erroneous data
while you are removing the DFARS from the ISS.
2. Remove the existing DFARS from the ISS
3. Disassemble the existing DFARS to perform the conversion
4. Install the new components into your DFARS
5. Solder battery wires to the PCBA
6. Reassemble the converted DFARS
7. Test the functionality of the fan with both battery and solar operation
8. Reinstall the radiation shield
9. Take the console out of Setup Mode
Remove & Disassemble the existing DFARS
It is important that you work on the conversion in a safe location, such as a workbench. To
do so, please perform the following steps after ensuring your console is in Setup Mode:
1. Locate the Sensor Interface Module (SIM) housing cover on the side of the ISS and
open it. This should be the cover that was used with your DFARS and has two solar
panels on it.
2. Disconnect the Solar Panel wire on the SIM cover from the SIM board by pulling the
Solar Panel connector. (Fig. 1)
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Figure 1
3. Disconnect the 2nd Solar Panel wire on the SIM cover from the power lead connected to
the DFARS fan. Set the SIM cover aside in a safe place. (Fig. 2)
Figure 2
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4. Remove the foam insert from the cable access port and set it aside. (Fig. 3)
Figure 3
5. Disconnect the existing cables from sensor connectors. These cables should all be
labeled – if your labels have fallen off, take note of which cables plug in where. (Fig. 4)
Figure 4
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6. For wired models, disconnect the console cable from the SIM. (Fig. 5)
Figure 5
7.
Feed the TEMP/HUM cable and the fan power cable through the back of the cable access port. (Fig. 6)
Figure 6
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8. Remove the rain collector cone by rotating the cone counter-clockwise until the cone’s
latches line up with the openings in the base. Lift off the rain collector cone and set aside
in a safe place. (Fig. 7)
Figure 7
9. While supporting the bottom of the DFARS, remove the (3) #8-32 x 3-1/4” screws, lock
washers and flat washers from the ISS base. IMPORTANT: Be sure to support the
bottom of the shield while removing the hardware. Save this hardware – it will be
used later. (Fig. 8)
Figure 8
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10. The DFARS should now be free of the ISS. Be careful – there is nothing holding the
closed cap plate and open cap plate at the top of the shield at this point. Take the
DFARS to your work area to perform the conversion.
11. Remove the closed cap plate and the open cap plate from the DFARS assembly. They
should just lift off. You should now be presented with the Fan Plate. (Fig. 9)
Figure 9
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Move Spacers
1. Remove the screw that holds the strain relief for the fan power cable and
temperature/humidity sensor. Remove the fan power cable from the strain relief and
disconnect from the fan. This cable will no longer be needed. Additionally, remove the
(3) 4” screws from the fan plate as indicated below. Save the 4” screws, washers, and
lock washers from this step, as well as the strain relief and its washer/screw. (Fig. 10).
Figure 10
2. Remove the fan from the housing by simply lifting it..
3. Lift the fan plate off of the existing plate stack, and place the remaining shield to the
side, being sure to keep them in the proper order.
4. Remove the existing spacers in the DFARS fan plate by removing the screw, lock
washer and flat washer from the bottom of the fan plate. These screws are located
under the fan plate (Fig. 11) Keep the spacers in a safe place, they will be needed later
in Section E. Only remove the existing spacers -- the screws, lock washers and flat
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washers will be used in the next step.
<- Keep these spacers for later.
Figure 11
Figure 12
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5. Install the 1.5” / Hex 2.25” spacers included in the kit in the place where you removed
the spacers in the previous step. Utilize the screws, lock washers, and flat washers from
the previous step to secure these longer spacers to the fan plate.
Install Battery Terminals into appropriate slots
1. Take the included battery terminal wires and use the terminal side of each wire to push
into the slot of each battery bay from underneath the fan plate. Push the leads through
the small hole on each side of each battery bay. Remember that the red connector
should be installed on the (+) side of the battery bay (labeled on the fan plate) and the
black connector should be installed on the opposite side. It helps to use the handle-end
of a screw driver to gently push the terminals into their slots so they are seated
properly. (Fig. 13)
Figure 13
2. When looking down at the fan plate, you will see an empty slot where the PCBA will be
installed. To the right of that, is a spacer and two small holes in the plate. Route the
lead ends of the battery connectors up from the bottom of the fan plate into these holes.
Route the pair of red wires through the left hole, and the pair of black wires through the
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right hole. (Fig. 14)
Figure 14
3. Using a wire stripper, strip appx 1/16” additional insulation from each of the leads. Twist
both red leads together, and twist both black leads together.
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Place the PCBA into the DFARS and Solder battery connectors
1. Temporarily secure the PCBA face-up into position where the leads can be soldered to
the board. Solder the red wires to the terminal marked BATT + on the RIGHT side of
the board (It will be necessary to flip the board over to perform the soldering). Do the
same for the black leads using the solder point just below the +
2. Once soldered, the PCBA can be secured to the fan plate with (2) #4-3/8” screws as
shown in Fig. 15. Push any excess wire through the two holes and make sure the wires
do not interfere with the lip of where the fan will be placed.
Figure 15
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3. Turn the fan plate over and use zip ties to tie up any excess wire between battery bays (Fig. 16)
Figure 16
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4. Insert each NiCd ‘C’ battery into its battery bay. The flat side of the battery is the (-) side
and the side with the button sticking out is the (+). It may be necessary to push the
battery tabs in slightly to make the batteries fit properly. Once the batteries are installed,
install the O-ring into the groove for each battery compartment (Fig. 17)
Figure 17
5. Install the battery covers by placing them on top of each battery. There is a notch in the
middle of each cover that should face towards the fan for proper orientation. Secure
each battery cover with (2) #4-3/8” self tapping screws.
Reassemble the radiation shield
1. Take the fan plate and place it back on the radiation shield plates. Route the
TEMP/HUM sensor wire so that it sits flat in the groove to the left of the fan PCBA. Place
the fan back in its appropriate spot, and plug its connector into the PCBA in the spot
marked MOTOR. FAN MAY SPIN AT THIS POINT. (Note tab on connector – it can
only be inserted one way). Additionally, prepare the strain relief that was removed in
Section B, Step 1 so that it holds the wire for the TEMP/HUM sensor. Do not screw the
strain relief down at this point, as the solar panel wire will also be included. (Fig. 18)
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Figure 18
2. Insert the 4” screws removed earlier along with the lock-washer and flat washer to
secure the fan plate to the remainder of the stack. Place the new solar panel next to the
radiation shield and connect its lead to the PCBA terminal marked SOL. Guide the wire
so it is in the strain relief. At this point, the strain relief can be screwed back to the fan
plate with its #4 flast washer and self-tapping screw. Attach the PCBA cover by
squeezing it and inserting it into the slots on each side of the PCBA. (Fig. 19)
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Figure 19
3. Place the open-end plate on top of the spacers. It may require some extra effort to
ensure the plate is seated at the top of the spacers. (Fig. 20)
Figure 20
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4. Place the closed plate on top of the open-end plate. (Fig. 21)
Figure 21
5. Install the solar panel on top of the threaded spacers, being sure the solar panel itself is
positioned directly over the exit point of the wires from the shield. Be sure to use the
holes indicated to place the solar panel on top of the shield. (NOTE: Using the wrong set
of holes will result in your solar panel being blocked by the SIM – do not use the holes
indicated below with red ‘X’s)
6. With the solar panel in position, place a #8 flat washer and a #8 lock-washer on top of
each threaded rod. Use the hex-shaped threaded spacers from included with your kit
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and HAND-TIGHTEN the spacers to the solar panel until the lock-washers are flush with
the top portion of the solar panel. Check each spacer twice.
7.
Before re-installing the radiation shield, ensure you hear the fan spinning under battery
and solar conditions. To test the battery power, bring the shield into a dark room. The
fan speed should slow when running under battery power. Bring the shield into the sun
so the solar panel receives bright light (a bright incandescent light can be used as well).
The fan should run at a higher speed.
Reinstall the radiation shield to the ISS
1. Place the radiation shield under the bottom of the rain collector base with the solar
panel facing south (if you are in the northern hemisphere).
2. Use the #8-32 x 1.25” screws included in the kit, along with the flat washers and lock
washers that you removed in Section A Step 9, attach the spacers at the top of the
solar panel shield to the base of the rain collector using the same holes that you
removed the 3-1/4” screws from in that same step. (Fig. 22)
Figure 222
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3. Feed the TEMP/HUM sensor wire back into the SIM using the access port on both
the bottom of the solar panel and the back of the SIM.
4. Reinstall the rain collector cone by lining up the tabs with the slots and then turning
the cone in a clock wise direction until it snaps into place.
5. Plug all connectors back into their respective jacks on the ISS.
6. Replace the foam insulation in the block where the access port is.
7. Reattach the connector from the top solar panel from the SIM cover included with
your DFARS to the appropriate connector on the SIM. The wire from the bottom
solar panel will not be connected. (NOTE: If you still have the original SIM cover
with one solar panel, you may replace the dual-panel SIM cover that came with the
DFARS with this.) If this is a cabled unit, this step does not apply.
8. Replace the SIM cover, being careful to ensure it is lined up with the SIM base
before sliding the cover down.
9. Take the console out of Setup Mode and ensure that communication is restored.
10. Use tie-wraps to secure any loose wires after your installation is complete.
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