Front Panel Mounting - Heathkit SB-401 Assembly Manual

( ) Start flat control washers and control nuts at
locations FG, FH, and FK. Do not tighten
the nuts at this time.
.
( ) Install the 2-contact female microphone
connector at FL, using the lockwasher and
nut supplied with the connector. Position the
lugs as shown. The lug numbers are molded
into the connector.
( ) Position the front panel on the chassis.
Place the zero set drive pulley shaft
through the hole in the upper right-hand
corner of the escutcheon.
( ) Push the zero set drive pulley flush with the
inside of the escutcheon and install the 7/16"
aluminum knob on the zero set drive pulley
shaft. Use a 4-40 x 1/8" setscrew.
( ) Apply a very thin layer of silicone grease
to the shaft of the dial drive pulley. Be very
careful not to get grease on the pulleys or
any other part of the Transmitter. Open the
silicone grease container by poking a small
hole in the top of the container.
( ) Push the dial drive bushing down so the dial
drive pulley engages with the circular dial
drive ring with just enough pressure to ro-
tate the circular dial without slippage. Tight-
en the dial drive bushing. The amount of tor-
que required to turn the circular dial can be
adjusted by moving the dial drive bushing
up or down.
( ) Remove the control nuts from the switches
at FG, FH, and FK.
( ) Secure the top corners of the front panel to
the chassts, using 6-32 x 3/8" phillips head
hardware.
( ) Slide the zero set drive pulley (small shaft)
onto the zero set dial. Position the pulley
and dial as shown.
( ) By carefully moving the front panel, aligp
the small hole in the center of the escutcheon
with the end of the LMO shaft. With the bot-
tom edge of the front panel parallel to an
imaginary horizontal line drawn through the
end of the LMO shaft, tighten the control
nuts at FG, FH, and FK.
NOTE: Check the alignment of the front flange
and side aprons again, at this time, to insure
smooth operation of the tuning dial. Refer to
Detail 3-1A on Page 16.
Refer to Pictorial 5-5 (fold-out from Page 76)
for the following steps.
( ) Slide the shaft of the dial drive pulley into
the bushing in the front panel. Push the
bushing up as far as it will go.
NOTE: The following adjustment of the front
panel is critical and must be done carefully to
obtain smooth operation of the dial mechanism.
FRONT PANEL MOUNTING
Page 81