Ramsey Electronics FZ-146 Specifications download pdf (Page 130)

FX 146 • 130

IMPORTANT:

DO NOT install any parts near Q8 until after Q8 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 Q8 correctly.

DO NOT INSTALL L9, R32 or L10 UNTIL AFTER ALIGNMENT HAS BEEN

COMPLETED.

C75 is a SMT (surface-mount-technology) "chip" capacitor and is the only

part installed on the SOLDER SIDE (bottom) of the board.

 TX1. Install Q9, RF NPN type 2N3866. Let it rest flush on the round

bare area of the board. The holes match the pins, so the tab will point

exactly as illustrated.

 TX2a. RF Final transistor Q8 (MRF237 or SD1127) is also installed

completely flush on the board, with the tab oriented toward L9. The

case of Q8 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 Q8'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 Q8. On the other hand, the lack of a good

heatsink bond WILL destroy Q8 when transmitting. This procedure is

INTENDED by the manufacturer.

 TX2b. Now, using only your regular soldering pen and NOT a soldering

"gun," solder the rim of Q8 directly to the top ground plane, starting at

the square tab. Use enough solder for thorough bonding.

 TX3

A. Prepare the following tools for installing SMT chip capacitor C75:

• Tweezers

• Magnifier (if needed)

• Low wattage, clean soldering tip.

C75

Location of C75

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Ramsey Electronics FZ-146 Specifications Page 130