BS-1
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12
Since you may appreciate some “warm-up” soldering practice as well as a
chance to put some “landmarks” on the PC board, we’ll first install some of the
larger components. Have a look at the Parts Layout Diagram to help with your
assembly.
1. Install S2, the Power DPDT horizontal push-button switch. It fits correctly
only one way. Ensure that the white plastic switch extends out over the
edge of the printed circuit board. Solder all six pins.
2. Install S1, the Record DPDT horizontal push-button switch.
3. Install S3, the Play DPDT horizontal push-button switch.
4. Install J5, the power jack. Solder all 3 pins.
5. Install J4, the sub-miniature speaker jack. Solder all 3 points of the jack
securely.
6. Install J6, the RCA jack (line input). Solder all 4 pins.
7. Install the two remaining RCA jacks J1 and J3. These are the line level
outputs. Don’t forget to solder all pins on both jacks.
OK, that was a good warm-up. Let’s take a look at those solder joints to make
sure we’re in good shape to move on. A good solder connection should be
shiny, smooth, and solid. No room for loose connections here! An old trick is to
wipe the hot tip of the iron across a damp sponge before soldering each
connection. This keeps the tip clean and spreads the heat faster for a solid
connection. If you haven’t tried it, give it a shot and see how much easier it
goes. Ready to move on?
8. Install the 28 pin DIP socket for U2. There is no right or wrong direction
to this socket, but the U2 IC itself certainly needs to be inserted correctly
(later). Before soldering, make sure the socket body is flush against the PC
board, and that all 28 pins have been inserted. Solder all 28 pins and then
CAREFULLY check to ensure you have not caused any "solder bridges"
between pins.
9. Install the 16 pin DIP socket for U4. Make sure all 16 pins made it
through the board and solder all pins.
10. Install U3, the audio amplifier IC LM386. Be careful you haven’t picked
up the LM358 by mistake. (these two chips are not interchangeable)
Observe proper orientation and solder all 8 pins.
11. Install U1, the LM358. Check for proper orientation of the notched end
and solder all 8 pins.
Now is a good time to double check your work. Loose pins, solder bridges, or
an improperly installed IC can really throw a wrench into the works. It’s also a
good time to take a break and maybe rub your eyes before you get back into it.
