T-238 Assembly Manual
Rev. 1 February 2001
Page 4 of 11
Now check your work. All leads should be soldered. There
should be no solder bridges or cold solder connections.
[ ] OK so far.
This completes the diode installation. You should have no
remaining diodes.
[ ] One LED remaining.
IC Sockets
NOTE
: If any socket pins are bent, carefully straighten
them with a pair of long-nose pliers before assembly.
Some types of IC sockets have crimps in the pins to hold
them in place when automatic wave soldering is
performed. These sockets may be tricky to install if you are
not familiar with them. If your kit contains these sockets,
you may want to straighten the pins before attempting to
insert them into the PC board.
When installing IC sockets double check to ensure that the
socket is seated properly against the board with the notch
matching the silk-screen. Pin 1 (nearest the socket notch)
has a square solder pad. Be sure that all IC socket pins
are showing on the solder side of the board. Next, tack-
solder two diagonally opposite corners first (such as pins 1
and 8 on a 14-pin socket).
Then solder the remaining pins of that socket before
proceeding to the next one. If you find a socket is difficult
to install, remove it and double-check for a bent pin.
CAUTION!
–
Take care to avoid solder bridges!
Install the following IC sockets. Align the notch in the
socket to the notch in the silkscreen outline:
[ ] U3 40-pin
[ ] U4 16-pin
Now check your work. All leads should be soldered. There
should be no solder bridges (a blob of solder that shorts
two adjacent soldered connections) or cold (gray and/or
grainy looking) solder connections.
[ ] OK so far.
This completes the IC socket installation.
Capacitors
All capacitors should be mounted as nearly flush to the
board surface as practical without stressing the leads.
Install the following capacitors:
[ ] C3 0.1 uF (104)
[ ] C4 0.1 uF (104)
[ ] C5 0.1 uF (104)
[ ] C6 0.1 uF (104)
[ ] C7 0.1 uF (104)
[ ] Solder and clip the leads (10 total)
Electrolytic and Tantalum capacitors are polarized. The
positive lead goes in the hole on the board marked with a
"+". Be careful! Typically the negative lead is marked but
sometimes the positive lead is marked.
NOTE:
The orientation of the of the positive “+” leads are
not all the same.
[ ] C8 1 uF (105 or 1+35)
[ ] C9 1 uF (105 or 1+35)
[ ] C10 1 uF (105 or 1+35)
[ ] C11 1 uF (105 or 1+35)
[ ] C12 1 uF (105 or 1+35)
[ ] Solder and clip the leads (10 total)
[ ] C1 10 uF
[ ] C2 10 uF
[ ] Solder and clip the leads (4 total)
Now check your work. All leads should be soldered. There
should be no solder bridges or cold solder connections.
[ ] OK so far.
This completes the capacitor installation. You should have
no remaining capacitors.
[ ] No capacitors remaining.
Ferrite Beads
Ferrite beads are cylinder shaped. String a clipped lead
from a resistor or capacitor though the ferrite bead.
Position the ferrite bead over the silkscreen outline and
insert the leads into the solder holes. Solder the leads and
clip them flush on the bottom of the PCB.
Install the following ferrite beads:
[ ] L1
[ ] L2
[ ] L3
[ ] L4
[ ] L5
[ ] L6
[ ] L7
[ ] L8 (Install the ferrite in the solid silkscreen outline. This
is the normal position. The dashed outline is an alternate
position.)
[ ] Solder and clip the leads (16 total)
Trimpot
Align the trimpot according to the silkscreen.
Install the trimpot:
[ ] V1 10K ohm
[ ] Solder and clip the leads (3 total)
Light Emitting Diode (LED)