Wantegrity HAWK-800 Series Constructions And Installations Instructions page 10

HAWK-800 Constructions and Installations Instructions –
main board and small secondary board from the Poly-800.
Set aside the 9 screws in a safe place where they will not be lost or misplaced.
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Carefully remove the main board (along with the RFI shield) and secondary board all together.
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Disconnect the RFI shield and set it aside in a safe place where it will not be lost or misplaced.
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Step 7 – Remove IC 29 from the main board
Discussion: IC29 is a 74HC138 3 of 8 decoder logic chip that is used to decode the address lines for the microprocessor. This
chip must be removed and replaced with a 16 pin DIP IC socket. This then allows a ribbon header cable to connect from
this socket to the new HAWK board. We provide three 74HC138 chips in the kit and the IC29 chip is not needed for the
HAWK to function. However, you should try to remove this chip intact so that testing can occur if the HAWK does not work
on its first attempt. So, if you take enough care while removing this chip then the chip can be reused for testing if needed.
RECOMMENDED: We recommend using a professional vacuum de-soldering station to remove IC29 and the EPROM socket.
Please use a professional vacuum de-soldering station if you have access to one.
NOTE: Do NOT over heat the chip and do NOT spend too much time with the solder braid. It is possible to overheat the
glue that binds the copper tracks to the fiberglass board. You should spend no more than 10 seconds at a time with the
soldering iron contacting each part of the board. Allow 20 seconds for the board to cool down each time you spend 10
seconds de-soldering.
Warm up your soldering iron and allow it to achieve normal operating temperature.
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Locate IC29 and familiarize yourself with its position while looking at the front and back of the board (you don't
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want to remove the wrong chip – see the picture below and use the chips around IC29 to get your reference).
Use de-soldering braid and the vacuum de-soldering
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tool to remove as much solder as possible from the
solder pads on the underside of the board.
You may find that once you have removed most of
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the solder the chip still tends to stay stuck in place
by tiny remaining amounts of solder. To free up each
pin, carefully wiggle each pin in turn using the tip of
the soldering iron just touching the very top of each
IC leg. Eventually, by wiggling each leg while the
solder is melted, the legs will become free.
Once you can see that each leg is free, use your long
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point tweezers (or the flat bladed screwdriver) to
gently lever the chip up from the surface of the PCB.
CAUTION: Use very little force while attempting to lever the chip from the board. If the chip will not move then most likely
you still have some amount of solder holding the chip in place. If you use too much force, you will most likely rip up copper
tracks off of the main board. This would be a disaster! Take your time. Don't rush it! See the picture above showing IC29
removed.
Step 8 – Installing the IC29 16 pin DIP Socket
Now install a 16 pin DIP socket where IC29 (the 74HC138) once was. Use the
picture below to determine the orientation of the socket. At one end of the socket
is a notch that is used as a pointer to determine where pin 1 of each chip should
be. You need to make sure that you get the orientation correct.
Carefully insert a 16 pin DIP socket into the location of IC29. Ensure that
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the notch of the socket matches the notch shown on the board itself. See
the pictures below.
https://www.hawk800.com
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