Ramsey Electronics FX-440 Manual page 87

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[ ] [ ~V'CR34b. Wind 2 turns of the enameled wire around through the
center of the toroid as illustrated. Trim away excess wire so that
you have two 1 /2" leads. Remove the enamel insulation from
these two leads as follows:"TIN" the ends of these leads by
heating them with your soldering iron tip while also applying
solder. The heat will melt ott the enamel insulatiM, and the
copper wire will accept the tinning solder nicely. Do this tinning
process on both wires almost up to the body of the toroid coil.
T1 TOROID
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WIND2TURNS
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THROUGH
CENTER~
r
[ I
rv(
CR34c. Install T1
I
soldering all 5 connections. The added
windings face R113; the original windings face C11 .
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,./"_/
[ ]
[\.~,~9R35.
Install C11, 100 pf.
~"
[ ] [>f
CR36. Install R113, 51 ohms (green-brown-black).
A "Theoretical" Test:
At this point in your work, you could actually receive strong local signals
by connecting an antenna wire at C17 and a high frequency signal
source (e.g. a signal generator) to the input of T1. The signal you would
receive would be on a frequency of the signal generator frequency plus
21.4 MHz. Because we have not yet constructed any of the input circuitry
(Stage DR), you would also hear any signal on the signal generator
frequency MINUS 21.4 MHz. There is no actual "need" to conduct such a
test, except for the simple satisfaction of learning and discovering.
PRECAUTION ON WIRING FOR CONTROLS. JACKS. ETC:
The volume control, squelch control, speaker jack and power cord are
installed quite early in the assembly sequence so that tests can be
conducted periodically during assembly. The disadvantage of this
approach is that there is considerable wear or strain on the various wire
connections as the PC board is repeatedly flipped back and forth during
assembly. This is a serious consideration because more radios and
computers malfunction because of broken wires than from electronic
parts going bad. For this very reason, such wiring is ordinarily done as a
final step in electronics assembly. To minimize damage to the control and
jack wiring, use one of the provided wire cable ties to hold down this
group of wires temporarily. Loop the tie through the PC board mounting
hole near U1 O's position, grouping the wires snugly to the PC board.
After fully assembling and testing the kit, the cable tie may be clipped off
to allow you to once again use the PC board mounting hole.
FX-440
Assm. 27