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Stage B: AUDIO AMPLIFIER CIRCUIT ASSEMBLY:
Some of the Stage "A" steps required more detailed explanation than simply
inserting and soldering parts. As we move along, there will be more and
more short "one liners"! The following steps will complete a working audio
amplifier ready to power up and test.
B1. Install U2, the LM380 IC. Be sure to orient the dotted or banded end
as illustrated. (The use of a DIP socket for U2 is NOT recommended,
even if you use sockets for the other IC's. Notice that most of U2's pins
are soldered to the PC board ground plane. This provides heat sinking
to the IC chip for proper heat dissipation.)
B2. Install C48, 4.7 or 10 uf electrolytic, observe correct polarity.
B3. Install C33, .01 uf disc capacitor (marked .01 or 103).
B4. Install C41, .1 uf disc capacitor (marked .1 or 104).
B5. Install R108, 2 ohm (red-black-gold).
B6. Install C34, 470 uf electrolytic. Watch out for correct polarity.
B7. Similarly, install C29, 330 uf electrolytic.
B8. Install C37, .01 uf disc capacitor (marked .01 or 103).
B9. Install NPN transistor Q6. Be sure to have identified it correctly as
one of the five 2N3904 transistors used in your kit, (Not one of the
2SC2498 RF transistors) and be sure to orient the flat side as illustrated.
Before soldering, press the transistor as far into its 3 holes as
reasonably possible.
B10. Install R109, 47K (yellow-violet-orange). Note that this is another of
numerous vertical installations of resistors. The body of such resistors
should be snug against the board at the designated hole, with the other
wire neatly looped into the other hole without needless excess.
B11. Cut three 8" lengths of hookup wire (or 8" of 3 conductor wire) to
connect the Volume Control to the three points designated on the PC
board. Strip and tin all six ends, referring back to Stage A instructions if
necessary or helpful.
B12. Refer to the drawing
and correctly interconnect
the Volume Control's three
lugs to the 3 connecting
points on the PC board.
FX PCBOARD
FUSE
IN
OUT
GND
PWR
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