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Monster Mux 32 Assembly Instructions:

Tools you will need:

  • Soldering iron with a fine tip, 35 Watts or less for electronics work
  • 60/40 rosin core solder (Do not use acid core solder on this kit!)
  • Diagonal cutters
  • Optional: Desoldering wick or desoldering pump, multimeter, desk clamp for holding work pieces steady

Parts List:

12 3 position Green Terminal Block
4 U1. U2. U3, U4: CD74HCT4351 8 channel multiplexer IC
1 U5: 74HC138 3-8 Line Decoder IC
2 8 pin SIP header
2 6 pin SIP header
1 0.1 uF ceramic capacitor
1 Push-button switch
1 MonsterMux 32 PCB


A few notes on soldering:

  • Heat the joint, not the solder directly. When heated properly by the iron, the solder should melt and flow into the joint once it is applied.

  • Always use enough heat when soldering, but do not overheat. The joints on this board should not need heating for more than 5 seconds each. If it takes longer, then your iron is not putting out enough heat, or the iron tip is contaminated. Wipe the tip on a wet sponge and try again.

  • A good solder joint is shiny. A dull, grainy-looking joint is indicative of a cold joint. Cold solder joints make poor mechanical and electrical connections. They can be fixed by reheating the joint, removing the old solder and resoldering the connection with new solder.

  • Keep the soldering iron tip clean. Wipe the iron tip on a moist (not soaking wet) sponge frequently to remove old flux, dross (oxidized solder), and other contaminants that can ruin your connection.

Install (Insert, solder, and trim the leads of) the capacitor first. This is located near the X9 terminal block.

Insert and solder U1, the CD74HCT4351 IC. Make sure the notch on the IC matches the notch shown on the PCB. The IC pins are usually a little too spread out to fit into the board when they come from the factory. Bend them gently inwards to fit them onto the PCB.


Install U2, U3, and U4, the rest of the CD74HCT4351 IC's.


Install U5, the 74HC138 IC.


Install the reset button.


Install the 8 and 6 pin headers. You can use an Arduino board to hold the pins in place while you solder them from the top. Make sure the Arduino is not plugged in while you do this!


Install terminal block X12. You'll have to find some way to hold the connector in place while you solder it on.


Install the rest of the terminal blocks. Each block has a tab that is used to connect to the next one. Slide the tab onto the next block to get a row of terminals before inserting into the PCB.


Double check each connection to make sure there are no cold solder joints. Once everything looks good, you are ready to start testing!

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