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Figure 32-Correct orientation for P1 on the selector board
Designation Value Description Done
Install the Relays
There are 16 identical relays, numbered K1-K16. Install them all. Here’s an installation
hint. As you put each relay in, bend down two diagonal corner pins to hold the relay in
place. That way all the relays will be held in place as you flip the board up and down. I
like to:
1. Install each relay separately, cinching the corner pins to retain the relays. I use the
blade of a small, flat screwdriver to fold two diagonal corner pins against the
board. Be sure to select and fold the pins in a way that won’t cause a solder bridge
to an adjacent trace.
2. Once all the relays are cinched and installed, lay the board upside down against
your work surface. This will keep all the relays flat against the PCB. Now, solder
all the relay pins. There are lots of them...be careful to get them all.
Alternatively, if you still have a piece of cardboard handy from the transistor installation,
you can do the same trick:
1. Insert all 16 relays into the PCB.
2. Place a piece of cardboard over the relays.
3. Hold the cardboard-relay-PCB sandwich together, and turn the sandwich upside
down.
4. If you’re careful, the relays will be in place, and ready to solder.
5. Make sure that the board is flat, and that the relay pin protrusion looks equal.
If you’re using this trick and like to be extra careful, just solder two diagonal leads for
each relay. That lets you flip the PCB to inspect that all the relays are flat to the board.
After that, you can finish soldering all the relay pins. Be careful to get all the relay pins!
Install the Transistors
Insert each transistor into the board, making sure that the shape of the transistor follows
the silk-screen outline on the PCB. Here’s an easy way to do it.
1. Cut the transistors leads close to the tape. This leaves them as long as possible
without having to deal with the adhesive from the tape.
2. Insert the ten transistors into the PCB.
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