Ramsey Electronics FX-440 Manual page 78

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.
[ ] i<B;.
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
h~
dissipation.)
,f'~4J
[ ] [~{ ~2. Install C48, .01 uf (marked .01 or 103).
[ ]
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B3. Install C33, .01 uf.
[ ] [ :] ~B4. Install C41, .1 uf (marked .1 or 104).
;"./
[ ] f/] BS. Install R108, 2 ohms (red-black-gold).
[ ] I
~r-~es.
Install C34, 470 uf. electrolytic. Watch out for correct
po~arity.
[ ] rvf/87. Similarly, install C29, 330 uf. electrolytic.
/
[ ] PA
8,8'. Install C37, .01 uf.
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,//
[ [.{ B9. Install NPN transistor
06.
Be sure to have identified it
correctly as one of the five 2N3904 transistors used in your kit,
(NOT the three 2SC2570 RF transistors) and be sure to orient the
flat side as illustrated. Before soldering, press the transistor as far
into,lts 3 holes as reasonably possible.
/
' /
[ ] {\J/131
O.
Install R109, 47K (yellow-violet-orange). Note that this is
/another of numerous VERTICAL installations of resistors. The
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body of such resistors should be snug against the board at the
I
designated hole, with the other wire neatly looped into the other
~
hole without needless excess.
I
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t
[ ] [\I
B11. Cut three
a·
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
I')
instructions if necessary (assembly page 12).
I'
[ ] 1\1
B12. Refer to the following drawing and correctly interconnect
the Volume Control's three lugs to the 3 connecting points on the
PC board.
Assm. 18
FX-440