AR2
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progress is not a bad thing and when you come back you'll have fresh eyes
and renewed vigor to finish. Hey, we all like to take frequent breaks here at
the factory . . . but management isn’t as kind to us as you can be to yourself!
14. Install U6, one of the LMC6482AIN ICs. It’s located near the center of
the PC board. You’ll see the PC board silkscreen shows a notch on one
end of the part; this corresponds to the notch on the IC and shows you
which way to place the part. Line up the notches, then make sure that all
pins are through the board. With no other parts installed (other than
surface mount) you can have the part sit flat on your bench and the board
will hold it in place. That way the part will sit flat on the board. That’s why
we’re putting the ICs in first! We typically solder the two corner pins, flip
the board over to check placement, then solder the rest. Be sure to solder
all 8 pins.
15. Install U8, the LM386 audio amplifier IC. It’s located near the back of
the board between the markings for J8 and J9. Again, line up the notch on
the part with the notch marked on the board, make sure the part is seated
flat, then solder all 8 pins.
16. In the same way, install U4, the SA602 mixer/oscillator chip. Be sure
you have it placed correctly before soldering.
17. Install U5, the other LMC6482AIN. You know all about orientation and
flatness by now so I’ll just let you work and get it soldered in.
18. Install U2, an MC145170P2 PLL chip. Solder all 16 pins when you’re
sure you’ve got it oriented correctly.
19. Next we’ll install the socket for our programmed chip, U1. It’s the
‘brains’ of the entire kit. There should be a notch on the socket and while it
doesn’t really matter which way the socket is installed (as long as you
plug the chip into in the right direction!) it’s probably a good idea to place
the notch to match the notch on the silkscreen.
20. Once all the pins on the socket are soldered insert the U1 IC into the
socket; it’s the one with a label. Insert it now so that you know where it is
and it will be safe. It helps to gently ‘roll’ the chip on one side and then the
other to keep the pins all lined up and push them in slightly. This makes it
easier to insert the chip into the socket. Be sure that all pins are in and
that none are bent under or sticking out before moving on to the next part.
While you’re clipping leads on the back side of the board you can also
check the solder joints and immediately touch up any that don’t look
right. You’re already looking at the connections closely and it’s a good
time to spot mistakes!
