Ramsey Electronics FX-440 Manual page 135

question on these parts, which also may be built up as you proceed.
IMPORTANT:
1. DO NOT install any parts near
08
until after
08
has been installed in
accord with the explicit directions in Step TX2. If you fail to
observe this caution, it will be virtually impossible to perform the
installation of 08 correctly.
2. DO NOT INSTALL L9 or L10 UNTIL AFTER ALIGNMENT HAS
BEEN COMPLETED.
3. C73, C75A and C75B are SMT (surface-mount-technology) "chip"
capacitors and are the only parts installed on the SOLDER SIDE
(bottom) of the board. •
7,
) ti
' 1
TX1. Install 09, RF N PN type M RF559. Let it rest flush on the
'round bare area of the board. The holes match the pins, so the
long lead will point exactly as illustrated.
( ) 1':1
TX2a RF Final transistor
08
(M RF630 or SD1444)
is also installed completely flush on the board, with the tab
oriented toward L9. The case of 08 is common to the emitter. Be
sure the case stays completely flat against the top ground plane
when soldering the 3 points.
READ CAREFULLY: The following procedure lets the top groundplane
serve as the heatsink for the RF final output transistor. Do not be hesitant
in making a smooth solder bond between OS's case and the board. An
ordinary soldering pencil tip applied to both the case and the
groundplane at the same time will NOT damage 08. On the other hand,
the lack of a good heatsink bond WILL destroy 08 when transmitting.
This procedure is INTENDED by the manufacturer.
[ ) [ >4
TX2b. Now, using only your regular soldering pen and NOT a
/ soldering "gun,• solder the rim of 08 directly to the top ground
plane, starting at the square tab. Use enough solder tor thorough
bonding.
[ 1 [
) TX3a Prepare the following tools for installing
SMT chip capacitors C73, 75A, 75B:
•Tweezers
• Magnifier (if needed)
• Low wattage, clean soldering tip.
b.
Unpack and study the design of the chip, noting both ends are
FX-440 Assrn. 73