User Guide

SK-301 “SOFT KEY” INSTALLATION INSTRUCTIONS

PARTS SUPPLIED WITH THIS KIT:

(1) SK-301 “Soft Key” Circuit Board Assembly

(1) Nylon Threaded Spacer

(2) 6-32 x ¼” Screws

(1) #8 Bent Solder Lug

(1) #6 Internal Tooth Lock Washer

To start the installation, read these instructions very carefully. Unplug the amplifier and

remove any input, output and control cables that may be connected to the back of the amplifier.

Remove the chassis from the case, turn the rear of the amp toward you, and remove the rear panel

and left corner piece from the chassis. You are now ready to proceed with the installation.

( ) The exact mounting location of the SK-301 is not too critical. Be sure to keep the leads as

short as possible. The most convenient place I have found is just to the left of the filament

choke.

( ) Turn the chassis over and mark a location approximately 1-1/8” in from the rear of the

chassis and 2-9/16” to the right of the center of the middle U-shaped cutout in the bottom

plate of the chassis. This is where the mounting spacer attaches to the SK-301 and also

the location of the hole for the mounting screw. The hole should be located nearly under

the inside tube sockets. Very carefully drill a hole that will clear a 6-32 screw at the point

you just marked (#27 drill). Do not use too much pressure because you want the drill to

stop after just penetrating the chassis. Clean up any burrs from the hole.

( ) Turn the amplifier back over. Remove the screw directly under the column of feed-throughs

located next to the filament choke. Place the 2-hole solder lug over this screw and re-install

the screw.

( ) Attach the threaded nylon spacer to the SK-301 through the large mounting hole in the

corner of the circuit board using one of the 6-32 x ¼” screws and tighten well without

stripping the threads in the spacer. Place the #6 lock washer onto the remaining 6-32 x ¼”

screw and put it through the hole you just drilled. Attach the nylon spacer (and circuit

board) to the chassis.

( ) In the following steps, route the wires under the SK-301 circuit board and/or under the

filament choke as required.

( ) Connect the BLACK wire from the SK-301 circuit board to the solder lug you just installed

and solder.

( ) Route the GREEN wire from the SK-301 circuit along the chassis and up into the

transformer compartment and connect GREEN wire to the right side of the bottom feed-

through (nearest the transformer) and solder.

( ) Route the RED wire from the SK-301 under the circuit board and connect to the top feed-

through and solder.

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SK-301 “SOFT KEY” INSTALLATION INSTRUCTIONS PART S SUPPLIED WITH T HIS KIT : (1) SK-301 “S oft Key” Circuit Board Assembly (1) Nylon Threaded Spacer (2) 6-32 x ¼” Screws (1) #8 Bent Solder Lug (1) #6 Internal Tooth Lock Washer To start the installation, read these instructions very carefully. Unplug the amplifier and remove any input, output and control ca bles that may be connec ted to the back of the amplifier.
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() Remove the small white wire from the center contact of the “antenna relay” jack. Remove the other end of this w ire from the solder post near the coax connec tor. () Route the BLUE wire from the SK-301 under the circuit board and connect to the center contac t of the “antenna relay” jack and solder. () Connect the YELLOW wire from the SK-301 circuit board to the solder post where the white wire was removed and solder. Note, there is a 39Ω resistor also connected to this post.