Vectronics VEC-131K - Manual (Page 21)

VEC-131K Owner's Manual Aircraft Receiver Kit
19
! ! 2. Identify coil L4, a tunable .074 uH inductor. It has a red coil form,
and is the taller of the two shielded coils.
! ! 3. Insert coil L4. The coil should be flush (not tilting) against the PC
board. (Some coils have shouldered tabs that limit insertion depth.)
! ! 4. On the solder side of the PC board, bend over the can tabs, and solder.
Make sure the can has not shifted and is still standing perfectly straight
and flush to the board. Solder and trim the two coil leads.
! ! 5. Find coil L5, a 10.7-MHz IF transformer with a green slotted slug.
! ! 6. Insert the IF transformer at location L5, making sure the 5 coil leads
are properly aligned with the mounting holes. On the solder side of
the PC board, bend over the can tabs and solder. Make sure L5 is
mounted flush to the board, and is still standing perfectly straight.
(Some coils have shouldered tabs that limit insertion depth.) Solder
and trim the five coil leads.
! ! 7. Find a 6" lenth of #24 enamel wire. This will be used to make a 4-turn
coil. You'll also need a 6-32 screw to use as a winding form.
! ! 8. Carefully straighten the length of wire, removing all bends and kinks.
(Drawing it over a plastic rounded surface such as a screwdriver
handle works well.) Firmly holding one end, carefully wind four (4)
full turns over the winding form as shown below. Each turn should
conform to the thread of the screw.
6-32 screw thread
4-turns #24 enameled wire
1/2" leads stripped
and tinned with solder
Important Note: The #24 wire provided for these coils uses a special heat-
strippable enamel insulation formulated to melt at high temperatures. This
should allow you to strip, clean, and tin each coil lead in a single operation
(tinning means applying a thin coating of solder to the wire). To do this, hold
your soldering iron tip against the lead end for several seconds while applying a
small amount of solder--an operation most easily done while the coil is still
mounted on its winding mandrel. Eventually, the enamel insulation should begin
breaking down, allowing solder to adhere to the wire. If your iron doesn't
generate enough heat to start this process, you may scrape the enamel away