19
Install the low-profile 18.432 MHz crystal ("S184ECSL") at X1,
near the speaker cutout. Make sure the crystal is seated flat against the
board, then solder. Use a minimum amount of solder to avoid a short
under the can.
Note:
Insulators are not needed for crystals. The solder
mask on the top of the board provides adequate insulation.
Install the 4 MHz crystal (X2) near the microcontroller (U1). Use
minimal solder. Excess solder may short the lead to the case under the
crystal.
X2 must be seated flat against the board, with no insulators
or other spacers under it, or the metal shield will not fit correctly.
Cut two 3/4" (19 mm) bare wires (use small component leads).
Insert a bare wire into the grounding hole provided just to the left of
X2.
Solder this wire to the side of the crystal can, not the top, or it
will prevent installation of the shield in a later step.
Keep soldering
time below 5 seconds; if it takes longer, your iron may not be hot enough,
or your iron tip may not be making good contact with the crystal can.
Turn the board over, then solder and trim X2's ground wire.
Ground crystal X1 using the second bare wire. X1 is low profile, so
the wire can be soldered to the top of the can. Avoid overheating. It may
help to pre-tin the crystal can before attaching the ground wire.
Install the 10-pin, dual-row (5x2) male connector at P1, but do not
solder yet. Figure 4 shows P1 as viewed from right side of the board. The
plastic part of the connector must be on the
top
side of the board, with
the long end of the pins pointed up. The short ends are inserted into the
board.
P1
Figure 4
Solder just one pin of P1, from the bottom side.
Note:
P1's plastic
body can melt if too much heat is applied, causing the pins to be mis-
positioned. Limit soldering time to 2 to 3 seconds.
Examine the placement of P1. If it is not flat against the board, re-
heat the soldered pin while pressing down on the connector.
Once P1 is in the right position, solder the remaining pins. Do not
trim the leads.
Install a 2N3904 transistor at Q8, near X1. (Use a magnifying glass
if necessary to identify TO-92 package transistors.)
The flat side of the
transistor must be oriented toward the flat side of its outline as shown in
Figure 5a.
Figure 5
Install another 2N3904 at Q5, which is on the right side of the board
near potentiometer R6 (labeled "BIAS SET").
Install voltage regulator U3 (78L05), which has a 3-lead TO-92
package like the 2N3904 transistor. U3 is located in the right-front corner
of the board near connector P1.
i
The MOSFET transistors to be installed in the following
steps can be easily damaged by static discharge. Before and during
installation of these devices, touch an unpainted, grounded metal
surface.
Install MOSFET transistors Q10, Q11, Q12 (2N7000), which are
located near the "KPA100" label. The flat side of each transistor must be
aligned with the flat side of its outline as shown in Figure 5a.
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Страница 1: ...1 Appendix G 100 W Stage and RS 232 I O K2 100 Rev H3 July 24 2017 E740035...
Страница 33: ...33 T4 5 6 GND J8 J3 J2 E1 FAN BLK RED BLACK RED B1 B2 B3 J7 J6 J2 J3 A2 A1 Fan Wires Solder Lug Figure 24...
Страница 42: ...42 Figure 33...
Страница 54: ...54 C C C Figure 40...
Страница 74: ...74 Parts Placment Drawing Bottom Side...