Heathkit IM-4180 - Page 8

Pes ed FIED ATELECITITS
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{ ) 7. Return to “Alignment Using Frequency
Counter” or to ‘Alignment Using FM Re-
” and rarcharck all of tha alhanmant
44th PK OE OU LAL UL Sst
steps cainider those headings; you should need
to make only slight adjustments to either coil
L202 or trimmer C211.
cei ver,
ea a
Proceed to “Main Circuit Board Calibration.”
Refer
to
Pictorials
5-2
and
6-2
(Illustration
Booklet,
Page
9)
as
you
perform
the
following
calibration
steps.
( JA On the front panel of the Meter, set all the
pushbutton switches to their “out” positions
{press lightly on adjacent buttons).
(t) On the main circuit board, make sure the green
jumper wire is connected to the 15V circuit
haard. ie et at ia, iy Bes |
yoOara, all other jyuiiper wires should be on their
adjacent NORM circuit board pins.
(, ) Push the ON-OFF switch to ON.
(A Push in the 2 kHz DEVIATION switch.
When the pointer swings upscale, stop.
Caretully turn the OFFSET control
counterclockwise until the meter pointer just
stops at “‘0.”, NOTE: You may wish to repeat this
b
step a few times to be sure.
Vv
«J Move the red jumper wire to the CAL pin.
(
(! }) Move the orange jumper wire to the TUNE pin.
(, ) Refer to Detail 6-2A and, using the coil align-
a ane
ment tool, adjust coil L101 as follows:
meter until you see the pointer rise rather
abruptly to a mid-scale or higher reading.
This is shown in the Detail as slope “A.”
PEAKING COIL L101
a {APPROXIMATE NUMBER OF
Detail 6-2A
C. Continue turning the slug four to six mare
turns as you watch the meter indication dip
and then slowly rise to a second pea Count
Ba Oe ge OS a ee a a ae Sonn aren Ge
the turnos Livilbl ine Lil st to the second poahk.
Stop.
t
NOTE: If you were to go clockwise beyond
eernn wnaal wr atar tha ad fha 4
the oCLUIIU PCa, tne meer in
would resemble slope “‘C.”
D.~ Turn the slug counterclockwise from the
eoonn mank 1/9 tha niim wenn ha
second proan 1/2 L1G number Gr: turns peée-
tween the two peaks. Stop at the mid-point
dip at “B.”
(J Push the ON-OFF switch to ON
t tool, turn CAL,
Lee E ent c
(J Using the trimmer alignme
control R138 and, as you watch the meter, set
the control for a top-scale reading « of exactly 20
on the 0-20 scale. NOTE: Repeat this operation
as necessary to just get the pointer to the right
(\.) On the main circuit board, return the yellow,
orange, and red jumper wires to their adjacent
NORM pins
(© ) Connect the violet wire to the adjacent NULL
connector pin.
This completes the ‘‘Alignment and Calibration” of
your FM Deviation Meter. Proceed to ‘Final
Assembly.”