Heathkit IG-18 - Tens Frequency Switch Prewiring

TENS FREQUENCY SWITCH
Refer to the top view of Pictorial 9 (fold-out
from this page) for the following steps.
( ) Fasten an ll-position rotary switch (#63-
487) in
chassis hole L. Use a control nut
turned down finger tight. Refer to the lugs
on the rear wafer for proper positioning of
the switch.
NOTE: Use 1% resistors in the following steps.
Center each resistor between the wafers before
soldering.
( ) Pass one lead of a 3300 n (3.3 kQ) resistor
through lug R5 (N8). Bend the lead so it lies
beside lugs R6 (N8) and R7 (N8); then connect
the end to lug R8 (N8). Do not allow the
lead to touch the switch spacer post or the
nut.
( )
Connect the other lead of this resistor to lug
F5 (8-1).
NOTE:
Where a wire passes through a connection
and then goes to another point (or passes beside
the connection and comes in contact with it),
it will count as two wires in the solder instruc-
tions (8-2), one entering and one leaving the
connection.
( ) Connect one lead of a 2500 Q (2.5 kQ)
rE;ls~stor to lug F6 (8-1). Insert the other lead
through lug R6 and around the wire passing
by R6 (8-3).
Connect a 10 kn resistor from lug F7
(8-1) to lug R7 (8-3).
( )
Connect a 5000 Q (5 kQ) resistor from lug
F8 (8-1) to lug R8 (N8). Be sure to solder
both lugs at F8.
Refer to the bottom view of Pictorial 9 for the
following steps.
( ) Pass one lead of a 3300 Q (3.3 kQ) resistor
through lug Fll (N8). Bend the lead so it lies
beside lugs F12 (N8) and Fl (NS); then con-
nect the end to lug F2 (N8). Now solder lug
Fll (8-2).
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2"
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( ) Connect the other lead of this resistor to lug
Rll (S-1).
Connect a 2500 n (2.5 kQ) resistor from
lug F12 (8-3) to lug R12 (8-1).
Connect a 10 kn resistor from lug Fl
(8-3) to lug R1 (8-1).
( )
Connect a 5000 Q (5 kQ) resistor from
lug F2 (N8) to lug R2 (8-1). 80lder both
lugs at R2.
( ) Prepare the
wire:
2" brown
5" brown
3-1/2" yellow
3" yellow
2-1/2" yellow
Connect the 2" brown
(8-3) and R5 (N8).
( ) Connect one end
lug R5 (8-4), The
will be connected
lengths of hookup
between lugs F2
5" brown wire to
end of
this wire
NOTE: In the next POSitiOIl tl1te three yellow
wires as shown in Pictorial 9.
( )
Connect one , the 2-1/2",
and the 3" wires to lug RIO (8-3).
Solder both The free ends of
these wires will be connected later.
This completes the prewiring of the Tens Fre-
quency switch. All should be soldered except
the lugs at F4 have nothing connected to
them and lug R8 which has a 5000 n resistor and
a wire attached to it. These lugs will be wired to
and soldered later. Remove the switch from the
chassis and set it aside until it is called for later.
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5"
l
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